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reattachment</title> <meta name="description" content="Search results for: reattachment"> <meta name="keywords" content="reattachment"> <meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1, maximum-scale=1, user-scalable=no"> <meta charset="utf-8"> <link href="https://cdn.waset.org/favicon.ico" type="image/x-icon" rel="shortcut icon"> <link href="https://cdn.waset.org/static/plugins/bootstrap-4.2.1/css/bootstrap.min.css" rel="stylesheet"> <link href="https://cdn.waset.org/static/plugins/fontawesome/css/all.min.css" rel="stylesheet"> <link href="https://cdn.waset.org/static/css/site.css?v=150220211555" rel="stylesheet"> </head> <body> <header> <div class="container"> <nav class="navbar navbar-expand-lg navbar-light"> <a class="navbar-brand" href="https://waset.org"> <img src="https://cdn.waset.org/static/images/wasetc.png" alt="Open Science Research Excellence" title="Open Science Research Excellence" /> </a> <button class="d-block d-lg-none navbar-toggler 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id="custom-search-input"> <div class="input-group"> <i class="fas fa-search"></i> <input type="text" class="search-query" name="q" placeholder="Author, Title, Abstract, Keywords" value="reattachment"> <input type="submit" class="btn_search" value="Search"> </div> </div> </form> </div> </div> <div class="row mt-3"> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Commenced</strong> in January 2007</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Frequency:</strong> Monthly</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Edition:</strong> International</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Paper Count:</strong> 25</div> </div> </div> </div> <h1 class="mt-3 mb-3 text-center" style="font-size:1.6rem;">Search results for: reattachment</h1> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">25</span> Prediction of Turbulent Separated Flow in a Wind Tunel</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Karima%20Boukhadia">Karima Boukhadia</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In the present study, the subsonic flow in an asymmetrical diffuser was simulated numerically using code CFX 11.0 and its generator of grid ICEM CFD. Two models of turbulence were tested: K- ε and K- ω SST. The results obtained showed that the K- ε model singularly over-estimates the speed value close to the wall and that the K- ω SST model is qualitatively in good agreement with the experimental results of Buice and Eaton 1997. They also showed that the separation and reattachment of the fluid on the tilted wall strongly depends on its angle of inclination and that the length of the zone of separation increases with the angle of inclination of the lower wall of the diffuser. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=asymmetric%20diffuser" title="asymmetric diffuser">asymmetric diffuser</a>, <a href="https://publications.waset.org/abstracts/search?q=separation" title=" separation"> separation</a>, <a href="https://publications.waset.org/abstracts/search?q=reattachment" title=" reattachment"> reattachment</a>, <a href="https://publications.waset.org/abstracts/search?q=tilt%20angle" title=" tilt angle"> tilt angle</a>, <a href="https://publications.waset.org/abstracts/search?q=separation%20zone" title=" separation zone"> separation zone</a> </p> <a href="https://publications.waset.org/abstracts/26379/prediction-of-turbulent-separated-flow-in-a-wind-tunel" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/26379.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">576</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">24</span> Effects of Roughness on Forward Facing Step in an Open Channel</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=S.%20M.%20Rifat">S. M. Rifat</a>, <a href="https://publications.waset.org/abstracts/search?q=Andr%C3%A9%20L.%20Marchildon"> André L. Marchildon</a>, <a href="https://publications.waset.org/abstracts/search?q=Mark%20F.%20Tachie"> Mark F. Tachie</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Experiments were performed to investigate the effects of roughness on the reattachment and redevelopment regions over a 12 mm forward facing step (FFS) in an open channel flow. The experiments were performed over an upstream smooth wall and a smooth FFS, an upstream wall coated with sandpaper 36 grit and a smooth FFS and an upstream rough wall produced from sandpaper 36 grit and a FFS coated with sandpaper 36 grit. To investigate only the wall roughness effects, Reynolds number, Froude number, aspect ratio and blockage ratio were kept constant. Upstream profiles showed reduced streamwise mean velocities close to the rough wall compared to the smooth wall, but the turbulence level was increased by upstream wall roughness. The reattachment length for the smooth-smooth wall experiment was 1.78h; however, when it is replaced with rough-smooth wall the reattachment length decreased to 1.53h. It was observed that the upstream roughness increased the physical size of contours of maximum turbulence level; however, the downstream roughness decreased both the size and magnitude of contours in the vicinity of the leading edge of the step. Quadrant analysis was performed to investigate the dominant Reynolds shear stress contribution in the recirculation region. The Reynolds shear stress and turbulent kinetic energy profiles after the reattachment showed slower recovery compared to the streamwise mean velocity, however all the profiles fairly collapse on their corresponding upstream profiles at x/h = 60. It was concluded that to obtain a complete collapse several more streamwise distances would be required. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=forward%20facing%20step" title="forward facing step">forward facing step</a>, <a href="https://publications.waset.org/abstracts/search?q=open%20channel" title=" open channel"> open channel</a>, <a href="https://publications.waset.org/abstracts/search?q=separated%20and%20reattached%20turbulent%20flows" title=" separated and reattached turbulent flows"> separated and reattached turbulent flows</a>, <a href="https://publications.waset.org/abstracts/search?q=wall%20roughness" title=" wall roughness"> wall roughness</a> </p> <a href="https://publications.waset.org/abstracts/37175/effects-of-roughness-on-forward-facing-step-in-an-open-channel" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/37175.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">385</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">23</span> Flow of a Second Order Fluid through Constricted Tube with Slip Velocity at Wall Using Integral Method</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Nosheen%20Zareen%20Khan">Nosheen Zareen Khan</a>, <a href="https://publications.waset.org/abstracts/search?q=Abdul%20Majeed%20Siddiqui"> Abdul Majeed Siddiqui</a>, <a href="https://publications.waset.org/abstracts/search?q=Muhammad%20Afzal%20Rana"> Muhammad Afzal Rana</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The steady flow of a second order fluid through constricted tube with slip velocity at wall is modeled and analyzed theoretically. The governing equations are simplified by implying no slip in radial direction. Based on Karman Pohlhausen procedure polynomial solution for axial velocity profile is presented. An expressions for pressure gradient, shear stress, separation and reattachment points and radial velocity are also calculated. The effect of slip and no slip velocity on velocity, shear stress, pressure gradient are discussed and depicted graphically. It is noted that when Reynolds number increases velocity of the fluid decreases in both slip and no slip conditions. It is also found that the wall shear stress, separation and reattachment points are strongly effected by Reynolds number. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=approximate%20solution" title="approximate solution">approximate solution</a>, <a href="https://publications.waset.org/abstracts/search?q=constricted%20tube" title=" constricted tube"> constricted tube</a>, <a href="https://publications.waset.org/abstracts/search?q=non-Newtonian%20fluids" title=" non-Newtonian fluids"> non-Newtonian fluids</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20number" title=" Reynolds number"> Reynolds number</a> </p> <a href="https://publications.waset.org/abstracts/34309/flow-of-a-second-order-fluid-through-constricted-tube-with-slip-velocity-at-wall-using-integral-method" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/34309.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">398</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">22</span> Effect of Clinical Parameters on Strength of Reattached Tooth Fragment in Anterior Teeth: Systematic Review and Meta-Analysis </h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Neeraj%20Malhotra">Neeraj Malhotra</a>, <a href="https://publications.waset.org/abstracts/search?q=Ramya%20Shenoy"> Ramya Shenoy</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Objective: To assess the effect of clinical parameters (bonding agent, preparation design & storage media) on the strength of reattached anterior tooth fragment. Methodology: This is a systematic review and meta-analysis for articles referred from MEDLINE, PUBMED, and GOOGLE SCHOLAR. The articles on tooth reattachment and clinical factors affecting fracture strength/bond strength/fracture resistance of the reattached tooth fragment in anterior teeth and published in English from 1999 to 2016 were included for final review. Results: Out of 120 shortlisted articles, 28 articles were included for the systematic review and meta-analysis based on 3 clinical parameters i.e. bonding agent, tooth preparation design & storage media. Forest plot & funnel plots were generated based on individual clinical parameter and their effect on strength of reattached anterior tooth fragment. Results based on analysis suggest combination of both conclusive evidence favoring the experimental group as well as in-conclusive evidence for individual parameter. Conclusion: There is limited evidence as there are fewer articles supporting each parameter in human teeth. Bonding agent had showed better outcome in selected studies. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bonding%20agent" title="bonding agent">bonding agent</a>, <a href="https://publications.waset.org/abstracts/search?q=bond%20strength" title=" bond strength"> bond strength</a>, <a href="https://publications.waset.org/abstracts/search?q=fracture%20strength" title=" fracture strength"> fracture strength</a>, <a href="https://publications.waset.org/abstracts/search?q=preparation%20design" title=" preparation design"> preparation design</a>, <a href="https://publications.waset.org/abstracts/search?q=reattachment" title=" reattachment"> reattachment</a>, <a href="https://publications.waset.org/abstracts/search?q=storage%20media" title=" storage media"> storage media</a> </p> <a href="https://publications.waset.org/abstracts/80832/effect-of-clinical-parameters-on-strength-of-reattached-tooth-fragment-in-anterior-teeth-systematic-review-and-meta-analysis" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/80832.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">178</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">21</span> Visual Outcome After 360-Degree Retinectomy in Total Rhegmatogenous Retinal Detachment with Advanced Proliferative Vitreoretinopathy: A Case Series</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Andriati%20Nadhilah%20Widyarini">Andriati Nadhilah Widyarini</a>, <a href="https://publications.waset.org/abstracts/search?q=Ezra%20Margareth"> Ezra Margareth</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Introduction: Rhegmatogenous retinal detachment is a condition where there’s a break in the retina, which allows the vitreous to directly enter the subretinal space. Proliferative vitreoretinopathy (PVR) may develop due to this condition and can result in a new break, which could cause traction on the previously detached retina. Various methods of therapy can be done to treat this complication. Case: This case series involved 2 eyes of 2 patients who had total retinal detachment with advanced PVR. Pars plana vitrectomy was performed, and a 360-degree retinectomy procedure with perfluorocarbon liquid usage was done. This was followed by endo laser retinopexy to surround the border of retinectomy. 5000 cs silicone oil was used in 1 eye, whereas 12% of perfluoropropane gas was used in the other eye as a tamponade. These procedures were performed with meticulous attention to prevent any fluid from entering the subretinal space. Postoperative examination showed attachment of the retina and improvement of the patient’s visual acuity. Both eyes’ intraocular pressure was in the normal range. One eye developed retinal displacement, but no other complications occurred. Discussion: Rhegmatogenous retinal detachment with advanced PVR is a complex situation for vitreoretinal surgeons. PVR is characterized by the growth and migration of preretinal or subretinal membranes. PVR is the most common cause of retinal reattachment failure. A 360-degree retinectomy is an alternative surgical method to overcome this condition. Objectives of this procedure are releasing retinal traction caused by PVR, reducing the recurrence rate of PVR, and reattaching the retina to the pigment epithelial surface. Conclusion: 360-degree retinectomy provides satisfactory retinal reattachment and visual outcome improvement in rhegmatogenous retinal detachment with advanced PVR. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=RRD" title="RRD">RRD</a>, <a href="https://publications.waset.org/abstracts/search?q=retinectomy" title=" retinectomy"> retinectomy</a>, <a href="https://publications.waset.org/abstracts/search?q=pars%20plana" title=" pars plana"> pars plana</a>, <a href="https://publications.waset.org/abstracts/search?q=advanced%20PVR" title=" advanced PVR"> advanced PVR</a> </p> <a href="https://publications.waset.org/abstracts/181173/visual-outcome-after-360-degree-retinectomy-in-total-rhegmatogenous-retinal-detachment-with-advanced-proliferative-vitreoretinopathy-a-case-series" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/181173.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">47</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">20</span> Laminar Separation Bubble Prediction over an Airfoil Using Transition SST Turbulence Model on Moderate Reynolds Number</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Younes%20El%20Khchine">Younes El Khchine</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohammed%20Sriti"> Mohammed Sriti</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A parametric study has been conducted to analyse the flow around S809 airfoil of a wind turbine in order to better understand the characteristics and effects of laminar separation bubble (LSB) on aerodynamic design for maximizing wind turbine efficiency. Numerical simulations were performed at low Reynolds numbers by solving the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations based on C-type structural mesh and using the γ-Reθt turbulence model. A two-dimensional study was conducted for the chord Reynolds number of 1×10⁵ and angles of attack (AoA) between 0 and 20.15 degrees. The simulation results obtained for the aerodynamic coefficients at various angles of attack (AoA) were compared with XFoil results. A sensitivity study was performed to examine the effects of Reynolds number and free-stream turbulence intensity on the location and length of the laminar separation bubble and the aerodynamic performances of wind turbines. The results show that increasing the Reynolds number leads to a delay in the laminar separation on the upper surface of the airfoil. The increase in Reynolds number leads to an accelerated transition process, and the turbulent reattachment point moves closer to the leading edge owing to an earlier reattachment of the turbulent shear layer. This leads to a considerable reduction in the length of the separation bubble as the Reynolds number is increased. The increase in the level of free-stream turbulence intensity leads to a decrease in separation bubble length and an increase in the lift coefficient while having negligible effects on the stall angle. When the AoA increased, the bubble on the suction airfoil surface was found to move upstream to the leading edge of the airfoil, that causes earlier laminar separation. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=laminar%20separation%20bubble" title="laminar separation bubble">laminar separation bubble</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulence%20intensity" title=" turbulence intensity"> turbulence intensity</a>, <a href="https://publications.waset.org/abstracts/search?q=S809%20airfoil" title=" S809 airfoil"> S809 airfoil</a>, <a href="https://publications.waset.org/abstracts/search?q=transition%20model" title=" transition model"> transition model</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20number" title=" Reynolds number"> Reynolds number</a> </p> <a href="https://publications.waset.org/abstracts/179140/laminar-separation-bubble-prediction-over-an-airfoil-using-transition-sst-turbulence-model-on-moderate-reynolds-number" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/179140.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">83</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">19</span> Numerical Study of Laminar Separation Bubble Over an Airfoil Using γ-ReθT SST Turbulence Model on Moderate Reynolds Number</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Younes%20El%20Khchine">Younes El Khchine</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A parametric study has been conducted to analyse the flow around S809 airfoil of a wind turbine in order to better understand the characteristics and effects of laminar separation bubble (LSB) on aerodynamic design for maximizing wind turbine efficiency. Numerical simulations were performed at low Reynolds numbers by solving the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations based on C-type structural mesh and using the γ-Reθt turbulence model. A two-dimensional study was conducted for the chord Reynolds number of 1×105 and angles of attack (AoA) between 0 and 20.15 degrees. The simulation results obtained for the aerodynamic coefficients at various angles of attack (AoA) were compared with XFoil results. A sensitivity study was performed to examine the effects of Reynolds number and free-stream turbulence intensity on the location and length of the laminar separation bubble and the aerodynamic performances of wind turbines. The results show that increasing the Reynolds number leads to a delay in the laminar separation on the upper surface of the airfoil. The increase in Reynolds number leads to an accelerated transition process, and the turbulent reattachment point moves closer to the leading edge owing to an earlier reattachment of the turbulent shear layer. This leads to a considerable reduction in the length of the separation bubble as the Reynolds number is increased. The increase in the level of free-stream turbulence intensity leads to a decrease in separation bubble length and an increase in the lift coefficient while having negligible effects on the stall angle. When the AoA increased, the bubble on the suction airfoil surface was found to move upstream to the leading edge of the airfoil, causing earlier laminar separation. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=laminar%20separation%20bubble" title="laminar separation bubble">laminar separation bubble</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulence%20intensity" title=" turbulence intensity"> turbulence intensity</a>, <a href="https://publications.waset.org/abstracts/search?q=s809%20airfoil" title=" s809 airfoil"> s809 airfoil</a>, <a href="https://publications.waset.org/abstracts/search?q=transition%20model" title=" transition model"> transition model</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20number" title=" Reynolds number"> Reynolds number</a> </p> <a href="https://publications.waset.org/abstracts/177425/numerical-study-of-laminar-separation-bubble-over-an-airfoil-using-gh-retht-sst-turbulence-model-on-moderate-reynolds-number" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/177425.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">70</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">18</span> Numerical Study of Laminar Separation Bubble Over an Airfoil Using γ-ReθT SST Turbulence Model on Moderate Reynolds Number</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Younes%20El%20Khchine">Younes El Khchine</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohammed%20Sriti"> Mohammed Sriti</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A parametric study has been conducted to analyse the flow around S809 airfoil of wind turbine in order to better understand the characteristics and effects of laminar separation bubble (LSB) on aerodynamic design for maximizing wind turbine efficiency. Numerical simulations were performed at low Reynolds number by solving the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations based on C-type structural mesh and using γ-Reθt turbulence model. Two-dimensional study was conducted for the chord Reynolds number of 1×105 and angles of attack (AoA) between 0 and 20.15 degrees. The simulation results obtained for the aerodynamic coefficients at various angles of attack (AoA) were compared with XFoil results. A sensitivity study was performed to examine the effects of Reynolds number and free-stream turbulence intensity on the location and length of laminar separation bubble and aerodynamic performances of wind turbine. The results show that increasing the Reynolds number leads to a delay in the laminar separation on the upper surface of the airfoil. The increase in Reynolds number leads to an accelerate transition process and the turbulent reattachment point move closer to the leading edge owing to an earlier reattachment of the turbulent shear layer. This leads to a considerable reduction in the length of the separation bubble as the Reynolds number is increased. The increase of the level of free-stream turbulence intensity leads to a decrease in separation bubble length and an increase the lift coefficient while having negligible effects on the stall angle. When the AoA increased, the bubble on the suction airfoil surface was found to moves upstream to leading edge of the airfoil that causes earlier laminar separation. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=laminar%20separation%20bubble" title="laminar separation bubble">laminar separation bubble</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulence%20intensity" title=" turbulence intensity"> turbulence intensity</a>, <a href="https://publications.waset.org/abstracts/search?q=S809%20airfoil" title=" S809 airfoil"> S809 airfoil</a>, <a href="https://publications.waset.org/abstracts/search?q=transition%20model" title=" transition model"> transition model</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20number" title=" Reynolds number"> Reynolds number</a> </p> <a href="https://publications.waset.org/abstracts/178912/numerical-study-of-laminar-separation-bubble-over-an-airfoil-using-gh-retht-sst-turbulence-model-on-moderate-reynolds-number" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/178912.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">85</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">17</span> Transitional Separation Bubble over a Rounded Backward Facing Step Due to a Temporally Applied Very High Adverse Pressure Gradient Followed by a Slow Adverse Pressure Gradient Applied at Inlet of the Profile</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Saikat%20Datta">Saikat Datta</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Incompressible laminar time-varying flow is investigated over a rounded backward-facing step for a triangular piston motion at the inlet of a straight channel with very high acceleration, followed by a slow deceleration experimentally and through numerical simulation. The backward-facing step is an important test-case as it embodies important flow characteristics such as separation point, reattachment length, and recirculation of flow. A sliding piston imparts two successive triangular velocities at the inlet, constant acceleration from rest, 0≤t≤t0, and constant deceleration to rest, t0≤t<t1. The temporal and spatial pressure gradient is varied by a controlled motion of the piston. The flow visualization and PIV data on a water channel where water flows from right to left reveal the locally separated region on the rounded backward-facing step is filled with much vortex-flow structure, which grows during the deceleration phase of the piston motion. The reattachment of the outer shear layer forming a separation bubble has also been discussed. The development of vortices has a wave-like pattern within the separated region, and the bubble depicts an open bubble topology. The maximum pressure gradient point where the first vortex is formed is confirmed through numerical simulations. The flow visualization data also shows a distinct growing vortex at the maximum pressure gradient point. Secondary vortices of opposite signs grow in the inner layer due to adverse pressure gradients induced by the primary vortices. The boundary layer thickness at the point of separation is used to quantify the type of wall-bound vortex formed inside the outer shear layer of the separation bubble. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=laminar%20boundary%20layer%20separation" title="laminar boundary layer separation">laminar boundary layer separation</a>, <a href="https://publications.waset.org/abstracts/search?q=rounded%20backward%20facing%20step" title=" rounded backward facing step"> rounded backward facing step</a>, <a href="https://publications.waset.org/abstracts/search?q=separation%20bubble" title=" separation bubble"> separation bubble</a>, <a href="https://publications.waset.org/abstracts/search?q=unsteady%20separation" title=" unsteady separation"> unsteady separation</a>, <a href="https://publications.waset.org/abstracts/search?q=unsteady%20vortex%20flows" title=" unsteady vortex flows"> unsteady vortex flows</a> </p> <a href="https://publications.waset.org/abstracts/167806/transitional-separation-bubble-over-a-rounded-backward-facing-step-due-to-a-temporally-applied-very-high-adverse-pressure-gradient-followed-by-a-slow-adverse-pressure-gradient-applied-at-inlet-of-the-profile" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/167806.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">66</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">16</span> Backward-Facing Step Measurements at Different Reynolds Numbers Using Acoustic Doppler Velocimetry</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Maria%20Amelia%20V.%20C.%20Araujo">Maria Amelia V. C. Araujo</a>, <a href="https://publications.waset.org/abstracts/search?q=Billy%20J.%20Araujo"> Billy J. Araujo</a>, <a href="https://publications.waset.org/abstracts/search?q=Brian%20Greenwood"> Brian Greenwood</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The flow over a backward-facing step is characterized by the presence of flow separation, recirculation and reattachment, for a simple geometry. This type of fluid behaviour takes place in many practical engineering applications, hence the reason for being investigated. Historically, fluid flows over a backward-facing step have been examined in many experiments using a variety of measuring techniques such as laser Doppler velocimetry (LDV), hot-wire anemometry, particle image velocimetry or hot-film sensors. However, some of these techniques cannot conveniently be used in separated flows or are too complicated and expensive. In this work, the applicability of the acoustic Doppler velocimetry (ADV) technique is investigated to such type of flows, at various Reynolds numbers corresponding to different flow regimes. The use of this measuring technique in separated flows is very difficult to find in literature. Besides, most of the situations where the Reynolds number effect is evaluated in separated flows are in numerical modelling. The ADV technique has the advantage in providing nearly non-invasive measurements, which is important in resolving turbulence. The ADV Nortek Vectrino+ was used to characterize the flow, in a recirculating laboratory flume, at various Reynolds Numbers (Reh = 3738, 5452, 7908 and 17388) based on the step height (h), in order to capture different flow regimes, and the results compared to those obtained using other measuring techniques. To compare results with other researchers, the step height, expansion ratio and the positions upstream and downstream the step were reproduced. The post-processing of the AVD records was performed using a customized numerical code, which implements several filtering techniques. Subsequently, the Vectrino noise level was evaluated by computing the power spectral density for the stream-wise horizontal velocity component. The normalized mean stream-wise velocity profiles, skin-friction coefficients and reattachment lengths were obtained for each Reh. Turbulent kinetic energy, Reynolds shear stresses and normal Reynolds stresses were determined for Reh = 7908. An uncertainty analysis was carried out, for the measured variables, using the moving block bootstrap technique. Low noise levels were obtained after implementing the post-processing techniques, showing their effectiveness. Besides, the errors obtained in the uncertainty analysis were relatively low, in general. For Reh = 7908, the normalized mean stream-wise velocity and turbulence profiles were compared directly with those acquired by other researchers using the LDV technique and a good agreement was found. The ADV technique proved to be able to characterize the flow properly over a backward-facing step, although additional caution should be taken for measurements very close to the bottom. The ADV measurements showed reliable results regarding: a) the stream-wise velocity profiles; b) the turbulent shear stress; c) the reattachment length; d) the identification of the transition from transitional to turbulent flows. Despite being a relatively inexpensive technique, acoustic Doppler velocimetry can be used with confidence in separated flows and thus very useful for numerical model validation. However, it is very important to perform adequate post-processing of the acquired data, to obtain low noise levels, thus decreasing the uncertainty. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=ADV" title="ADV">ADV</a>, <a href="https://publications.waset.org/abstracts/search?q=experimental%20data" title=" experimental data"> experimental data</a>, <a href="https://publications.waset.org/abstracts/search?q=multiple%20Reynolds%20number" title=" multiple Reynolds number"> multiple Reynolds number</a>, <a href="https://publications.waset.org/abstracts/search?q=post-processing" title=" post-processing"> post-processing</a> </p> <a href="https://publications.waset.org/abstracts/110603/backward-facing-step-measurements-at-different-reynolds-numbers-using-acoustic-doppler-velocimetry" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/110603.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">148</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">15</span> Jet Impingement Heat Transfer on a Rib-Roughened Flat Plate</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=A.%20H.%20Alenezi">A. H. Alenezi</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Cooling by impingement jet is known to have a significant high local and average heat transfer coefficient which make it widely used in industrial cooling systems. The heat transfer characteristics of an impinging jet on rib-roughened flat plate has been investigated numerically. This paper was set out to investigate the effect of rib height on the heat transfer rate. Since the flow needs to have enough spacing after passing the rib to allow reattachment especially for high Reynolds numbers, this study focuses on finding the optimum rib height which would be the best to maximize the heat transfer rate downstream the plate. This investigation employs a round nozzle with hydraulic diameter (Dh) of 13.5 mm, Jet-to-target distance of (H/D) of 4, rib location=1.5D and and finally jet angels of 45˚ and 90˚ under the influence of Re =10,000. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=jet%20impingement" title="jet impingement">jet impingement</a>, <a href="https://publications.waset.org/abstracts/search?q=CFD" title=" CFD"> CFD</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulence%20model" title=" turbulence model"> turbulence model</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20transfer" title=" heat transfer"> heat transfer</a> </p> <a href="https://publications.waset.org/abstracts/57530/jet-impingement-heat-transfer-on-a-rib-roughened-flat-plate" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/57530.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">351</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">14</span> Numerical Study of Heat Transfer in Square Duct with Turbulators </h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=M.%20H.%20Alhajeri">M. H. Alhajeri</a>, <a href="https://publications.waset.org/abstracts/search?q=Hamad%20M.%20Alhajeri"> Hamad M. Alhajeri</a>, <a href="https://publications.waset.org/abstracts/search?q=A.%20H.%20Alenezi"> A. H. Alenezi</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Computational fluid dynamics (CFD) investigation of heat transfer in U-duct with turbulators is presented in this paper. The duct passages used to cool internally the blades in gas turbine. The study is focused in the flow behavior and the Nusselt number (Nu) distributions. The model of the u-duct contains two square legs that are connected by 180* turn. Four turbulators are located in each surface of the leg and distributed in a staggered arrangement. The turbulator height and width are equal to 0.1 of the duct width, and the turbulator height is 0.1 of the distance between the turbulators. The Reynolds number (Re) used in this study is 95000 and the inlet velocity is 10 m/s. It was noticed that, after the flow resettles from the interruptions generated by the first turbulator or the turn, the flow construct two eddies, one large and the other is small after and before the turbulator, respectively. The maximum values of the Nu are found at a distance of approximately one turbulator width w before of the flow reattachment point. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=computational%20fluid%20dynamics" title="computational fluid dynamics">computational fluid dynamics</a>, <a href="https://publications.waset.org/abstracts/search?q=CFD" title=" CFD"> CFD</a>, <a href="https://publications.waset.org/abstracts/search?q=rib" title=" rib"> rib</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20transfer" title=" heat transfer"> heat transfer</a>, <a href="https://publications.waset.org/abstracts/search?q=blade" title=" blade"> blade</a> </p> <a href="https://publications.waset.org/abstracts/109523/numerical-study-of-heat-transfer-in-square-duct-with-turbulators" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/109523.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">151</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">13</span> A Comparative CFD Study on the Hemodynamics of Flow through an Idealized Symmetric and Asymmetric Stenosed Arteries</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=B.%20Prashantha">B. Prashantha</a>, <a href="https://publications.waset.org/abstracts/search?q=S.%20Anish"> S. Anish</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The aim of the present study is to computationally evaluate the hemodynamic factors which affect the formation of atherosclerosis and plaque rupture in the human artery. An increase of atherosclerosis disease in the artery causes geometry changes, which results in hemodynamic changes such as flow separation, reattachment, and adhesion of new cells (chemotactic) in the artery. Hence, geometry plays an important role in the determining the nature of hemodynamic patterns. Influence of stenosis in the non-bifurcating artery, under pulsatile flow condition, has been studied on an idealized geometry. Analysis of flow through symmetric and asymmetric stenosis in the artery revealed the significance of oscillating shear index (OSI), flow separation, low WSS zones and secondary flow patterns on plaque formation. The observed characteristic of flow in the post-stenotic region highlight the importance of plaque eccentricity on the formation of secondary stenosis on the arterial wall. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=atherosclerotic%20plaque" title="atherosclerotic plaque">atherosclerotic plaque</a>, <a href="https://publications.waset.org/abstracts/search?q=oscillatory%20shear%20index" title=" oscillatory shear index"> oscillatory shear index</a>, <a href="https://publications.waset.org/abstracts/search?q=stenosis%20nature" title=" stenosis nature"> stenosis nature</a>, <a href="https://publications.waset.org/abstracts/search?q=wall%20shear%20stress" title=" wall shear stress"> wall shear stress</a> </p> <a href="https://publications.waset.org/abstracts/48939/a-comparative-cfd-study-on-the-hemodynamics-of-flow-through-an-idealized-symmetric-and-asymmetric-stenosed-arteries" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/48939.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">350</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">12</span> Effects of Upstream Wall Roughness on Separated Turbulent Flow over a Forward Facing Step in an Open Channel</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=S.%20M.%20Rifat">S. M. Rifat</a>, <a href="https://publications.waset.org/abstracts/search?q=Andr%C3%A9%20L.%20Marchildon"> André L. Marchildon</a>, <a href="https://publications.waset.org/abstracts/search?q=Mark%20F.%20Tachie"> Mark F. Tachie</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The effect of upstream surface roughness over a smooth forward facing step in an open channel was investigated using a particle image velocimetry technique. Three different upstream surface topographies consisting of hydraulically smooth wall, sandpaper 36 grit and sand grains were examined. Besides the wall roughness conditions, all other upstream flow characteristics were kept constant. It was also observed that upstream roughness decreased the approach velocity by 2% and 10% but increased the turbulence intensity by 14% and 35% at the wall-normal distance corresponding to the top plane of the step compared to smooth upstream. The results showed that roughness decreased the reattachment lengths by 14% and 30% compared to smooth upstream. Although the magnitudes of maximum positive and negative Reynolds shear stress in separated and reattached region were 0.02Ue for all the cases, the physical size of both the maximum and minimum contour levels were decreased by increasing upstream roughness. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=forward%20facing%20step" title="forward facing step">forward facing step</a>, <a href="https://publications.waset.org/abstracts/search?q=open%20channel" title=" open channel"> open channel</a>, <a href="https://publications.waset.org/abstracts/search?q=separated%20and%20reattached%20turbulent%20flows" title=" separated and reattached turbulent flows"> separated and reattached turbulent flows</a>, <a href="https://publications.waset.org/abstracts/search?q=wall%20roughness" title=" wall roughness"> wall roughness</a> </p> <a href="https://publications.waset.org/abstracts/37174/effects-of-upstream-wall-roughness-on-separated-turbulent-flow-over-a-forward-facing-step-in-an-open-channel" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/37174.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">355</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">11</span> The Flow Separation Delay on the Aircraft Wing</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ishtiaq%20A.%20Chaudhry">Ishtiaq A. Chaudhry</a>, <a href="https://publications.waset.org/abstracts/search?q=Z.%20R.%20Tahir"> Z. R. Tahir</a>, <a href="https://publications.waset.org/abstracts/search?q=F.%20A.%20Siddiqui"> F. A. Siddiqui</a>, <a href="https://publications.waset.org/abstracts/search?q=Z.%20Anwar"> Z. Anwar</a>, <a href="https://publications.waset.org/abstracts/search?q=F.%20Valenzuelacalva"> F. Valenzuelacalva</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A series of experiments involving the particle image velocimetry technique are carried out to analyse the quantitative effectiveness of the synthesized vortical structures towards actual flow separation control. The streamwise vortices are synthesized from the synthetic jet actuator and introduced into the attached and separating boundary layer developed on the flat plate surface. Two types of actuators with different geometrical set up are used to analyse the evolution of vortical structures in the near wall region and their impact towards achieving separation delay on the actual aircraft wing. Firstly a single circular jet is synthesized at varying actuator operating parameters and issued into the boundary layer to evaluate the dynamics of the interaction between the vortical structures and the near wall low momentum fluid in the separated region. Secondly, an array of jets has been issued into the artificially separated region to assess the effectiveness of various vortical structures towards achieving the reattachment of the separated flow in the streamwise direction. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=boundary%20layer" title="boundary layer">boundary layer</a>, <a href="https://publications.waset.org/abstracts/search?q=flow%20separation" title=" flow separation"> flow separation</a>, <a href="https://publications.waset.org/abstracts/search?q=streamwise%20vortices" title=" streamwise vortices"> streamwise vortices</a>, <a href="https://publications.waset.org/abstracts/search?q=synthetic%20jet%20actuator" title=" synthetic jet actuator"> synthetic jet actuator</a> </p> <a href="https://publications.waset.org/abstracts/16402/the-flow-separation-delay-on-the-aircraft-wing" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/16402.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">462</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">10</span> Modeling Flow and Deposition Characteristics of Solid CO2 during Choked Flow of CO2 Pipeline in CCS</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Teng%20lin">Teng lin</a>, <a href="https://publications.waset.org/abstracts/search?q=Li%20Yuxing"> Li Yuxing</a>, <a href="https://publications.waset.org/abstracts/search?q=Han%20Hui">Han Hui</a>, <a href="https://publications.waset.org/abstracts/search?q=Zhao%20Pengfei"> Zhao Pengfei</a>, <a href="https://publications.waset.org/abstracts/search?q=Zhang%20Datong"> Zhang Datong</a> </p> <p class="card-text"><strong>Abstract:</strong></p> With the development of carbon capture and storage (CCS), the flow assurance of CO2 transportation becomes more important, particularly for supercritical CO2 pipelines. The relieving system using the choke valve is applied to control the pressure in CO2 pipeline. However, the temperature of fluid would drop rapidly because of Joule-Thomson cooling (JTC), which may cause solid CO2 form and block the pipe. In this paper, a Computational Fluid Dynamic (CFD) model, using the modified Lagrangian method, Reynold's Stress Transport model (RSM) for turbulence and stochastic tracking model (STM) for particle trajectory, was developed to predict the deposition characteristic of solid carbon dioxide. The model predictions were in good agreement with the experiment data published in the literature. It can be observed that the particle distribution affected the deposition behavior. In the region of the sudden expansion, the smaller particles accumulated tightly on the wall were dominant for pipe blockage. On the contrary, the size of solid CO2 particles deposited near the outlet usually was bigger and the stacked structure was looser. According to the calculation results, the movement of the particles can be regarded as the main four types: turbulent motion close to the sudden expansion structure, balanced motion at sudden expansion-middle region, inertial motion near the outlet and the escape. Furthermore the particle deposits accumulated primarily in the sudden expansion region, reattachment region and outlet region because of the four type of motion. Also the Stokes number had an effect on the deposition ratio and it is recommended for Stokes number to avoid 3-8St. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=carbon%20capture%20and%20storage" title="carbon capture and storage">carbon capture and storage</a>, <a href="https://publications.waset.org/abstracts/search?q=carbon%20dioxide%20pipeline" title=" carbon dioxide pipeline"> carbon dioxide pipeline</a>, <a href="https://publications.waset.org/abstracts/search?q=gas-particle%20flow" title=" gas-particle flow"> gas-particle flow</a>, <a href="https://publications.waset.org/abstracts/search?q=deposition" title=" deposition "> deposition </a> </p> <a href="https://publications.waset.org/abstracts/41429/modeling-flow-and-deposition-characteristics-of-solid-co2-during-choked-flow-of-co2-pipeline-in-ccs" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/41429.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">369</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9</span> Dynamic and Thermal Characteristics of Three-Dimensional Turbulent Offset Jet</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ali%20Assoudi">Ali Assoudi</a>, <a href="https://publications.waset.org/abstracts/search?q=Sabra%20Habli"> Sabra Habli</a>, <a href="https://publications.waset.org/abstracts/search?q=Nejla%20Mahjoub%20Sa%C3%AFd"> Nejla Mahjoub Saïd</a>, <a href="https://publications.waset.org/abstracts/search?q=Philippe%20Bournot"> Philippe Bournot</a>, <a href="https://publications.waset.org/abstracts/search?q=Georges%20Le%20Palec"> Georges Le Palec</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Studying the flow characteristics of a turbulent offset jet is an important topic among researchers across the world because of its various engineering applications. Some of the common examples include: injection and carburetor systems, entrainment and mixing process in gas turbine and boiler combustion chambers, Thrust-augmenting ejectors for V/STOL aircrafts and HVAC systems, environmental dischargers, film cooling and many others. An offset jet is formed when a jet discharges into a medium above a horizontal solid wall parallel to the axis of the jet exit but which is offset by a certain distance. The structure of a turbulent offset-jet can be described by three main regions. Close to the nozzle exit, an offset jet possesses characteristic features similar to those of free jets. Then, the entrainment of fluid between the jet, the offset wall and the bottom wall creates a low pressure zone, forcing the jet to deflect towards the wall and eventually attaches to it at the impingement point. This is referred to as the Coanda effect. Further downstream after the reattachment point, the offset jet has the characteristics of a wall jet flow. Therefore, the offset jet has characteristics of free, impingement and wall jets, and it is relatively more complex compared to these types of flows. The present study examines the dynamic and thermal evolution of a 3D turbulent offset jet with different offset height ratio (the ratio of the distance from the jet exit to the impingement bottom wall and the jet nozzle diameter). To achieve this purpose a numerical study was conducted to investigate a three-dimensional offset jet flow through the resolution of the different governing Navier–Stokes’ equations by means of the finite volume method and the RSM second-order turbulent closure model. A detailed discussion has been provided on the flow and thermal characteristics in the form of streamlines, mean velocity vector, pressure field and Reynolds stresses. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=offset%20jet" title="offset jet">offset jet</a>, <a href="https://publications.waset.org/abstracts/search?q=offset%20ratio" title=" offset ratio"> offset ratio</a>, <a href="https://publications.waset.org/abstracts/search?q=numerical%20simulation" title=" numerical simulation"> numerical simulation</a>, <a href="https://publications.waset.org/abstracts/search?q=RSM" title=" RSM"> RSM</a> </p> <a href="https://publications.waset.org/abstracts/46805/dynamic-and-thermal-characteristics-of-three-dimensional-turbulent-offset-jet" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/46805.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">304</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">8</span> Numerical Investigation of Dynamic Stall over a Wind Turbine Pitching Airfoil by Using OpenFOAM</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Mahbod%20Seyednia">Mahbod Seyednia</a>, <a href="https://publications.waset.org/abstracts/search?q=Shidvash%20Vakilipour"> Shidvash Vakilipour</a>, <a href="https://publications.waset.org/abstracts/search?q=Mehran%20Masdari"> Mehran Masdari</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Computations for two-dimensional flow past a stationary and harmonically pitching wind turbine airfoil at a moderate value of Reynolds number (400000) are carried out by progressively increasing the angle of attack for stationary airfoil and at fixed pitching frequencies for rotary one. The incompressible Navier-Stokes equations in conjunction with Unsteady Reynolds Average Navier-Stokes (URANS) equations for turbulence modeling are solved by OpenFOAM package to investigate the aerodynamic phenomena occurred at stationary and pitching conditions on a NACA 6-series wind turbine airfoil. The aim of this study is to enhance the accuracy of numerical simulation in predicting the aerodynamic behavior of an oscillating airfoil in OpenFOAM. Hence, for turbulence modelling, <em>k-ω-SST</em> with low-Reynolds correction is employed to capture the unsteady phenomena occurred in stationary and oscillating motion of the airfoil. Using aerodynamic and pressure coefficients along with flow patterns, the unsteady aerodynamics at pre-, near-, and post-static stall regions are analyzed in harmonically pitching airfoil, and the results are validated with the corresponding experimental data possessed by the authors. The results indicate that implementing the mentioned turbulence model leads to accurate prediction of the angle of static stall for stationary airfoil and flow separation, dynamic stall phenomenon, and reattachment of the flow on the surface of airfoil for pitching one. Due to the geometry of the studied 6-series airfoil, the vortex on the upper surface of the airfoil during upstrokes is formed at the trailing edge. Therefore, the pattern flow obtained by our numerical simulations represents the formation and change of the trailing-edge vortex at near- and post-stall regions where this process determines the dynamic stall phenomenon. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=CFD" title="CFD">CFD</a>, <a href="https://publications.waset.org/abstracts/search?q=moderate%20Reynolds%20number" title=" moderate Reynolds number"> moderate Reynolds number</a>, <a href="https://publications.waset.org/abstracts/search?q=OpenFOAM" title=" OpenFOAM"> OpenFOAM</a>, <a href="https://publications.waset.org/abstracts/search?q=pitching%20oscillation" title=" pitching oscillation"> pitching oscillation</a>, <a href="https://publications.waset.org/abstracts/search?q=unsteady%20aerodynamics" title=" unsteady aerodynamics"> unsteady aerodynamics</a>, <a href="https://publications.waset.org/abstracts/search?q=wind%20turbine" title=" wind turbine"> wind turbine</a> </p> <a href="https://publications.waset.org/abstracts/76029/numerical-investigation-of-dynamic-stall-over-a-wind-turbine-pitching-airfoil-by-using-openfoam" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/76029.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">203</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">7</span> Arthroscopic Fixation of Posterior Cruciate Ligament Avulsion Fracture through Posterior Trans Septal Portal Using Button Fixation Device: Mini Tight Rope</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ratnakar%20Rao">Ratnakar Rao</a>, <a href="https://publications.waset.org/abstracts/search?q=Subair%20Khan"> Subair Khan</a>, <a href="https://publications.waset.org/abstracts/search?q=Hari%20Haran"> Hari Haran </a> </p> <p class="card-text"><strong>Abstract:</strong></p> Posterior cruciate ligament (PCL) avulsion fractures is a rare condition and commonly mismanaged.Surgical reattachment has been shown to produce better result compared with conservative management.Only few techniques are reported in arthroscopic fixation of PCL Avulsion Fracture and they are complex.We describe a new technique in fixation of the PCL Avulsion fracture through a posterior trans septal portal using button fixation device (Mini Tight Rope). Eighteen patients with an isolated posterior cruciate ligament avulsion fracture were operated under arthroscopy. Standard Antero Medial Portal and Antero Lateral portals made and additional Postero Medial and Postero Lateral portals made and trans Septal portal established. Avulsion fracture identified, elevated, prepared. Reduction achieved using PCL Tibial guide (Arthrex) and fixation was achieved using Mini Tight Rope,Arthrex (2 buttons with a suture). Reduction confirmed using probe and Image intensifier. Postoperative assessment made clinically and radiologically. 15 patients had good to excellent results with no posterior sag or instability. The range of motion was normal. No complications were recorded per operatively. 2 patients had communition of the fragment while drilling, for one patient it was managed by suturing technique and the second patient PCL Reconstruction was done. One patient had persistent instability with poor outcome. Establishing trans septal portal helps in better visualization of the posterior compartment of the knee. Assessment of the bony fragment, preparation 0f the bone bed andit protects from injury to posterior neurovascular structures. Fixation using the button with suture (Mini Tight Rope) is stable and easily reproducible for PCL Avulsion fracture with single large fragment. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=PCL%20avulsion" title="PCL avulsion">PCL avulsion</a>, <a href="https://publications.waset.org/abstracts/search?q=arthroscopy" title=" arthroscopy"> arthroscopy</a>, <a href="https://publications.waset.org/abstracts/search?q=transeptal" title=" transeptal"> transeptal</a>, <a href="https://publications.waset.org/abstracts/search?q=minitight%20rope%20technique" title=" minitight rope technique"> minitight rope technique</a> </p> <a href="https://publications.waset.org/abstracts/16166/arthroscopic-fixation-of-posterior-cruciate-ligament-avulsion-fracture-through-posterior-trans-septal-portal-using-button-fixation-device-mini-tight-rope" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/16166.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">256</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">6</span> Strategic Innovation of Nanotechnology: Novel Applications of Biomimetics and Microfluidics in Food Safety</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Boce%20Zhang">Boce Zhang</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Strategic innovation of nanotechnology to promote food safety has drawn tremendous attentions among research groups, which includes the need for research support during the implementation of the Food Safety Modernization Act (FSMA) in the United States. There are urgent demands and knowledge gaps to the understanding of a) food-water-bacteria interface as for how pathogens persist and transmit during food processing and storage; b) minimum processing requirement needed to prevent pathogen cross-contamination in the food system. These knowledge gaps are of critical importance to the food industry. However, the lack of knowledge is largely hindered by the limitations of research tools. Our groups recently endeavored two novel engineering systems with biomimetics and microfluidics as a holistic approach to hazard analysis and risk mitigation, which provided unprecedented research opportunities to study pathogen behavior, in particular, contamination, and cross-contamination, at the critical food-water-pathogen interface. First, biomimetically-patterned surfaces (BPS) were developed to replicate the identical surface topography and chemistry of a natural food surface. We demonstrated that BPS is a superior research tool that empowers the study of a) how pathogens persist through sanitizer treatment, b) how to apply fluidic shear-force and surface tension to increase the vulnerability of the bacterial cells, by detaching them from a protected area, etc. Secondly, microfluidic devices were designed and fabricated to study the bactericidal kinetics in the sub-second time frame (0.1~1 second). The sub-second kinetics is critical because the cross-contamination process, which includes detachment, migration, and reattachment, can occur in a very short timeframe. With this microfluidic device, we were able to simulate and study these sub-second cross-contamination scenarios, and to further investigate the minimum sanitizer concentration needed to sufficiently prevent pathogen cross-contamination during the food processing. We anticipate that the findings from these studies will provide critical insight on bacterial behavior at the food-water-cell interface, and the kinetics of bacterial inactivation from a broad range of sanitizers and processing conditions, thus facilitating the development and implementation of science-based food safety regulations and practices to mitigate the food safety risks. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=biomimetic%20materials" title="biomimetic materials">biomimetic materials</a>, <a href="https://publications.waset.org/abstracts/search?q=microbial%20food%20safety" title=" microbial food safety"> microbial food safety</a>, <a href="https://publications.waset.org/abstracts/search?q=microfluidic%20device" title=" microfluidic device"> microfluidic device</a>, <a href="https://publications.waset.org/abstracts/search?q=nanotechnology" title=" nanotechnology"> nanotechnology</a> </p> <a href="https://publications.waset.org/abstracts/68073/strategic-innovation-of-nanotechnology-novel-applications-of-biomimetics-and-microfluidics-in-food-safety" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/68073.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">359</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">5</span> Modeling of Turbulent Flow for Two-Dimensional Backward-Facing Step Flow</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Alex%20Fedoseyev">Alex Fedoseyev</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This study investigates a generalized hydrodynamic equation (GHE) simplified model for the simulation of turbulent flow over a two-dimensional backward-facing step (BFS) at Reynolds number Re=132000. The GHE were derived from the generalized Boltzmann equation (GBE). GBE was obtained by first principles from the chain of Bogolubov kinetic equations and considers particles of finite dimensions. The GHE has additional terms, temporal and spatial fluctuations, compared to the Navier-Stokes equations (NSE). These terms have a timescale multiplier τ, and the GHE becomes the NSE when $\tau$ is zero. The nondimensional τ is a product of the Reynolds number and the squared length scale ratio, τ=Re*(l/L)², where l is the apparent Kolmogorov length scale, and L is a hydrodynamic length scale. The BFS flow modeling results obtained by 2D calculations cannot match the experimental data for Re>450. One or two additional equations are required for the turbulence model to be added to the NSE, which typically has two to five parameters to be tuned for specific problems. It is shown that the GHE does not require an additional turbulence model, whereas the turbulent velocity results are in good agreement with the experimental results. A review of several studies on the simulation of flow over the BFS from 1980 to 2023 is provided. Most of these studies used different turbulence models when Re>1000. In this study, the 2D turbulent flow over a BFS with height H=L/3 (where L is the channel height) at Reynolds number Re=132000 was investigated using numerical solutions of the GHE (by a finite-element method) and compared to the solutions from the Navier-Stokes equations, k–ε turbulence model, and experimental results. The comparison included the velocity profiles at X/L=5.33 (near the end of the recirculation zone, available from the experiment), recirculation zone length, and velocity flow field. The mean velocity of NSE was obtained by averaging the solution over the number of time steps. The solution with a standard k −ε model shows a velocity profile at X/L=5.33, which has no backward flow. A standard k−ε model underpredicts the experimental recirculation zone length X/L=7.0∓0.5 by a substantial amount of 20-25%, and a more sophisticated turbulence model is needed for this problem. The obtained data confirm that the GHE results are in good agreement with the experimental results for turbulent flow over two-dimensional BFS. A turbulence model was not required in this case. The computations were stable. The solution time for the GHE is the same or less than that for the NSE and significantly less than that for the NSE with the turbulence model. The proposed approach was limited to 2D and only one Reynolds number. Further work will extend this approach to 3D flow and a higher Re. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=backward-facing%20step" title="backward-facing step">backward-facing step</a>, <a href="https://publications.waset.org/abstracts/search?q=comparison%20with%20experimental%20data" title=" comparison with experimental data"> comparison with experimental data</a>, <a href="https://publications.waset.org/abstracts/search?q=generalized%20hydrodynamic%20equations" title=" generalized hydrodynamic equations"> generalized hydrodynamic equations</a>, <a href="https://publications.waset.org/abstracts/search?q=separation" title=" separation"> separation</a>, <a href="https://publications.waset.org/abstracts/search?q=reattachment" title=" reattachment"> reattachment</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulent%20flow" title=" turbulent flow"> turbulent flow</a> </p> <a href="https://publications.waset.org/abstracts/179240/modeling-of-turbulent-flow-for-two-dimensional-backward-facing-step-flow" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/179240.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">61</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4</span> Studies on Pre-ignition Chamber Dynamics of Solid Rockets with Different Port Geometries</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=S.%20Vivek">S. Vivek</a>, <a href="https://publications.waset.org/abstracts/search?q=Sharad%20Sharan"> Sharad Sharan</a>, <a href="https://publications.waset.org/abstracts/search?q=R.%20Arvind"> R. Arvind</a>, <a href="https://publications.waset.org/abstracts/search?q=D.%20V.%20Praveen"> D. V. Praveen</a>, <a href="https://publications.waset.org/abstracts/search?q=J.%20Vigneshwar"> J. Vigneshwar</a>, <a href="https://publications.waset.org/abstracts/search?q=S.%20Ajith"> S. Ajith</a>, <a href="https://publications.waset.org/abstracts/search?q=V.%20R.%20Sanal%20Kumar"> V. R. Sanal Kumar</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this paper numerical studies have been carried out to examine the starting transient flow features of high-performance solid propellant rocket motors with different port geometries but with same propellant loading density. Numerical computations have been carried out using a 3D SST k-ω turbulence model. This code solves standard k-omega turbulence equations with shear flow corrections using a coupled second order implicit unsteady formulation. In the numerical study, a fully implicit finite volume scheme of the compressible, Reynolds-Averaged, Navier-Stokes equations are employed. We have observed from the numerical results that in solid rocket motors with highly loaded propellants having divergent port geometry the hot igniter gases can create pre-ignition thrust oscillations due to flow unsteadiness and recirculation. Under these conditions the convective flux to the surface of the propellant will be enhanced, which will create reattachment point far downstream of the transition region and it will create a situation for secondary ignition and formation of multiple-flame fronts. As a result the effective time required for the complete burning surface area to be ignited comes down drastically giving rise to a high pressurization rate (dp/dt) in the second phase of starting transient. This in effect could lead to starting thrust oscillations and eventually a hard start of the solid rocket motor. We have also observed that the igniter temperature fluctuations will be diminished rapidly and will reach the steady state value faster in the case of solid propellant rocket motors with convergent port than the divergent port irrespective of the igniter total pressure. We have concluded that the thrust oscillations and unexpected thrust spike often observed in solid rockets with non-uniform ports are presumably contributed due to the joint effects of the geometry dependent driving forces, transient burning and the chamber gas dynamics forces. We also concluded that the prudent selection of the port geometry, without altering the propellant loading density, for damping the total temperature fluctuations within the motor is a meaningful objective for the suppression and control of instability and/or pressure/thrust oscillations often observed in solid propellant rocket motors with non-uniform port geometry. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=ignition%20transient" title="ignition transient">ignition transient</a>, <a href="https://publications.waset.org/abstracts/search?q=solid%20rockets" title=" solid rockets"> solid rockets</a>, <a href="https://publications.waset.org/abstracts/search?q=starting%20transient" title=" starting transient"> starting transient</a>, <a href="https://publications.waset.org/abstracts/search?q=thrust%20transient" title=" thrust transient"> thrust transient</a> </p> <a href="https://publications.waset.org/abstracts/35068/studies-on-pre-ignition-chamber-dynamics-of-solid-rockets-with-different-port-geometries" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/35068.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">449</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">3</span> A Hybrid LES-RANS Approach to Analyse Coupled Heat Transfer and Vortex Structures in Separated and Reattached Turbulent Flows</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=C.%20D.%20Ellis">C. D. Ellis</a>, <a href="https://publications.waset.org/abstracts/search?q=H.%20Xia"> H. Xia</a>, <a href="https://publications.waset.org/abstracts/search?q=X.%20Chen"> X. Chen</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Experimental and computational studies investigating heat transfer in separated flows have been of increasing importance over the last 60 years, as efforts are being made to understand and improve the efficiency of components such as combustors, turbines, heat exchangers, nuclear reactors and cooling channels. Understanding of not only the time-mean heat transfer properties but also the unsteady properties is vital for design of these components. As computational power increases, more sophisticated methods of modelling these flows become available for use. The hybrid LES-RANS approach has been applied to a blunt leading edge flat plate, utilising a structured grid at a moderate Reynolds number of 20300 based on the plate thickness. In the region close to the wall, the RANS method is implemented for two turbulence models; the one equation Spalart-Allmaras model and Menter’s two equation SST k-ω model. The LES region occupies the flow away from the wall and is formulated without any explicit subgrid scale LES modelling. Hybridisation is achieved between the two methods by the blending of the nearest wall distance. Validation of the flow was obtained by assessing the mean velocity profiles in comparison to similar studies. Identifying the vortex structures of the flow was obtained by utilising the λ2 criterion to identify vortex cores. The qualitative structure of the flow compared with experiments of similar Reynolds number. This identified the 2D roll up of the shear layer, breaking down via the Kelvin-Helmholtz instability. Through this instability the flow progressed into hairpin like structures, elongating as they advanced downstream. Proper Orthogonal Decomposition (POD) analysis has been performed on the full flow field and upon the surface temperature of the plate. As expected, the breakdown of POD modes for the full field revealed a relatively slow decay compared to the surface temperature field. Both POD fields identified the most energetic fluctuations occurred in the separated and recirculation region of the flow. Latter modes of the surface temperature identified these levels of fluctuations to dominate the time-mean region of maximum heat transfer and flow reattachment. In addition to the current research, work will be conducted in tracking the movement of the vortex cores and the location and magnitude of temperature hot spots upon the plate. This information will support the POD and statistical analysis performed to further identify qualitative relationships between the vortex dynamics and the response of the surface heat transfer. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=heat%20transfer" title="heat transfer">heat transfer</a>, <a href="https://publications.waset.org/abstracts/search?q=hybrid%20LES-RANS" title=" hybrid LES-RANS"> hybrid LES-RANS</a>, <a href="https://publications.waset.org/abstracts/search?q=separated%20and%20reattached%20flow" title=" separated and reattached flow"> separated and reattached flow</a>, <a href="https://publications.waset.org/abstracts/search?q=vortex%20dynamics" title=" vortex dynamics"> vortex dynamics</a> </p> <a href="https://publications.waset.org/abstracts/61406/a-hybrid-les-rans-approach-to-analyse-coupled-heat-transfer-and-vortex-structures-in-separated-and-reattached-turbulent-flows" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/61406.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">231</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2</span> Wind Tunnel Tests on Ground-Mounted and Roof-Mounted Photovoltaic Array Systems</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Chao-Yang%20Huang">Chao-Yang Huang</a>, <a href="https://publications.waset.org/abstracts/search?q=Rwey-Hua%20Cherng"> Rwey-Hua Cherng</a>, <a href="https://publications.waset.org/abstracts/search?q=Chung-Lin%20Fu"> Chung-Lin Fu</a>, <a href="https://publications.waset.org/abstracts/search?q=Yuan-Lung%20Lo"> Yuan-Lung Lo</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Solar energy is one of the replaceable choices to reduce the CO2 emission produced by conventional power plants in the modern society. As an island which is frequently visited by strong typhoons and earthquakes, it is an urgent issue for Taiwan to make an effort in revising the local regulations to strengthen the safety design of photovoltaic systems. Currently, the Taiwanese code for wind resistant design of structures does not have a clear explanation on photovoltaic systems, especially when the systems are arranged in arrayed format. Furthermore, when the arrayed photovoltaic system is mounted on the rooftop, the approaching flow is significantly altered by the building and led to different pressure pattern in the different area of the photovoltaic system. In this study, L-shape arrayed photovoltaic system is mounted on the ground of the wind tunnel and then mounted on the building rooftop. The system is consisted of 60 PV models. Each panel model is equivalent to a full size of 3.0 m in depth and 10.0 m in length. Six pressure taps are installed on the upper surface of the panel model and the other six are on the bottom surface to measure the net pressures. Wind attack angle is varied from 0° to 360° in a 10° interval for the worst concern due to wind direction. The sampling rate of the pressure scanning system is set as high enough to precisely estimate the peak pressure and at least 20 samples are recorded for good ensemble average stability. Each sample is equivalent to 10-minute time length in full scale. All the scale factors, including timescale, length scale, and velocity scale, are properly verified by similarity rules in low wind speed wind tunnel environment. The purpose of L-shape arrayed system is for the understanding the pressure characteristics at the corner area. Extreme value analysis is applied to obtain the design pressure coefficient for each net pressure. The commonly utilized Cook-and-Mayne coefficient, 78%, is set to the target non-exceedance probability for design pressure coefficients under Gumbel distribution. Best linear unbiased estimator method is utilized for the Gumbel parameter identification. Careful time moving averaging method is also concerned in data processing. Results show that when the arrayed photovoltaic system is mounted on the ground, the first row of the panels reveals stronger positive pressure than that mounted on the rooftop. Due to the flow separation occurring at the building edge, the first row of the panels on the rooftop is most in negative pressures; the last row, on the other hand, shows positive pressures because of the flow reattachment. Different areas also have different pressure patterns, which corresponds well to the regulations in ASCE7-16 describing the area division for design values. Several minor observations are found according to parametric studies, such as rooftop edge effect, parapet effect, building aspect effect, row interval effect, and so on. General comments are then made for the proposal of regulation revision in Taiwanese code. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=aerodynamic%20force%20coefficient" title="aerodynamic force coefficient">aerodynamic force coefficient</a>, <a href="https://publications.waset.org/abstracts/search?q=ground-mounted" title=" ground-mounted"> ground-mounted</a>, <a href="https://publications.waset.org/abstracts/search?q=roof-mounted" title=" roof-mounted"> roof-mounted</a>, <a href="https://publications.waset.org/abstracts/search?q=wind%20tunnel%20test" title=" wind tunnel test"> wind tunnel test</a>, <a href="https://publications.waset.org/abstracts/search?q=photovoltaic" title=" photovoltaic"> photovoltaic</a> </p> <a href="https://publications.waset.org/abstracts/98046/wind-tunnel-tests-on-ground-mounted-and-roof-mounted-photovoltaic-array-systems" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/98046.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">138</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">1</span> Restoring Total Form and Function in Patients with Lower Limb Bony Defects Utilizing Patient-Specific Fused Deposition Modelling- A Neoteric Multidisciplinary Reconstructive Approach</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Divya%20SY.%20Ang">Divya SY. Ang</a>, <a href="https://publications.waset.org/abstracts/search?q=Mark%20B.%20Tan"> Mark B. Tan</a>, <a href="https://publications.waset.org/abstracts/search?q=Nicholas%20EM.%20Yeo"> Nicholas EM. Yeo</a>, <a href="https://publications.waset.org/abstracts/search?q=Siti%20RB.%20Sudirman"> Siti RB. Sudirman</a>, <a href="https://publications.waset.org/abstracts/search?q=Khong%20Yik%20Chew"> Khong Yik Chew</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Introduction: The importance of the amalgamation of technological and engineering advances with surgical principles of reconstruction cannot be overemphasized. With earlier detection of cancer, consequences of high-speed living and neglect, like traumatic injuries and infection, resulting in increasingly younger patients with bone defects. This may result in malformations and suboptimal function that is more noticeable and palpable in the younger, active demographic. Our team proposes a technique that encapsulates a mesh of multidisciplinary effort, tissue engineering and reconstructive principles. Methods/Materials: Our patient was a young competitive footballer in his early 30s who was diagnosed with submandibular adenoid cystic carcinoma with bony involvement. He was thus counselled for a right hemi mandibulectomy, the floor of mouth resection, right selective neck dissection, tracheostomy, and free fibular flap reconstruction of his mandible and required post-operative radiotherapy. Being young and in his prime sportsman years, he was unable to accept the morbidities associated with using his fibula to reconstruct his mandible despite it being the gold standard reconstructive option. The fibula is an ideal vascularized bone flap because it’s reliable and easily shaped with relatively minimal impact on functional outcomes. The fibula contributes to 30% of weightbearing and is the attachment for the lateral compartment muscles; it is stronger in footballers concerning lateral bending. When harvesting the fibula, the distal 6-8cm and up to 10% of the total length is preserved to maintain the ankle’s stability, thus, minimizing the impact on daily activities. There are studies that have noted gait variability post-operatively. Therefore, returning to a premorbid competitive level may be doubtful. To improve his functional outcomes, the decision was made to try and restore the fibula's form and function. Using the concept of Fused Deposition Modelling (FDM), our team comprising of Plastics, Otolaryngology, Orthopedics and Radiology, worked with Osteopore to design a 3D bioresorbable implant to regenerate the fibula defect (14.5cm). Bone marrow was harvested via reaming the contralateral hip prior to the wide resection. 30mls of his blood was obtained for extracting platelet rich plasma. These were packed into the Osteopore 3D-printed bone scaffold. This was then secured into the fibula defect with titanium plates and screws. The flexor hallucis longus and soleus were anchored along the construct and intraosseous membrane, done in a single setting. Results: He was reviewed closely as an outpatient over 10 months post operatively. He reported no discernable loss or difference in ankle function. He is satisfied and back in training and our team has video and photographs that substantiate his progress. Conclusion: FDM allows regeneration of long bone defects. However, we aimed to also restore his eversion and inversion that is imperative for footballers and hence reattached his previously dissected muscles along the length of the Osteopore implant. We believe that the reattachment of the muscle stabilizes not only the construct but allows optimum muscle tensioning when moving his ankle. This is a simple but effective technique in restoring complete function and form in a young patient whose minute muscle control is imperative to life. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=fused%20deposition%20modelling" title="fused deposition modelling">fused deposition modelling</a>, <a href="https://publications.waset.org/abstracts/search?q=functional%20reconstruction" title=" functional reconstruction"> functional reconstruction</a>, <a href="https://publications.waset.org/abstracts/search?q=lower%20limb%20bony%20defects" title=" lower limb bony defects"> lower limb bony defects</a>, <a href="https://publications.waset.org/abstracts/search?q=regenerative%20surgery" title=" regenerative surgery"> regenerative surgery</a>, <a href="https://publications.waset.org/abstracts/search?q=3D%20printing" title=" 3D printing"> 3D printing</a>, <a href="https://publications.waset.org/abstracts/search?q=tissue%20engineering" title=" tissue engineering"> tissue engineering</a> </p> <a href="https://publications.waset.org/abstracts/165790/restoring-total-form-and-function-in-patients-with-lower-limb-bony-defects-utilizing-patient-specific-fused-deposition-modelling-a-neoteric-multidisciplinary-reconstructive-approach" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/165790.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">73</span> </span> </div> </div> </div> </main> <footer> <div id="infolinks" class="pt-3 pb-2"> <div class="container"> <div style="background-color:#f5f5f5;" class="p-3"> <div class="row"> <div class="col-md-2"> <ul class="list-unstyled"> About <li><a href="https://waset.org/page/support">About Us</a></li> <li><a href="https://waset.org/page/support#legal-information">Legal</a></li> <li><a target="_blank" rel="nofollow" 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