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k-ω SST model</title> <meta name="description" content="Search results for: low Reynolds k-ω SST model"> <meta name="keywords" content="low Reynolds k-ω SST model"> <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 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action="https://publications.waset.org/abstracts/search"> <div 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="low Reynolds k-ω SST model"> <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> 17003</div> </div> </div> </div> <h1 class="mt-3 mb-3 text-center" style="font-size:1.6rem;">Search results for: low Reynolds k-ω SST model</h1> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">17003</span> Assessment of Modern RANS Models for the C3X Vane Film Cooling Prediction</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Mikhail%20Gritskevich">Mikhail Gritskevich</a>, <a href="https://publications.waset.org/abstracts/search?q=Sebastian%20Hohenstein"> Sebastian Hohenstein</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The paper presents the results of a detailed assessment of several modern Reynolds Averaged Navier-Stokes (RANS) turbulence models for prediction of C3X vane film cooling at various injection regimes. Three models are considered, namely the Shear Stress Transport (SST) model, the modification of the SST model accounting for the streamlines curvature (SST-CC), and the Explicit Algebraic Reynolds Stress Model (EARSM). It is shown that all the considered models face with a problem in prediction of the adiabatic effectiveness in the vicinity of the cooling holes; however, accounting for the Reynolds stress anisotropy within the EARSM model noticeably increases the solution accuracy. On the other hand, further downstream all the models provide a reasonable agreement with the experimental data for the adiabatic effectiveness and among the considered models the most accurate results are obtained with the use EARMS. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=discrete%20holes%20film%20cooling" title="discrete holes film cooling">discrete holes film cooling</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20Averaged%20Navier-Stokes%20%28RANS%29" title=" Reynolds Averaged Navier-Stokes (RANS)"> Reynolds Averaged Navier-Stokes (RANS)</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20stress%20tensor%20anisotropy" title=" Reynolds stress tensor anisotropy"> Reynolds stress tensor anisotropy</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulent%20heat%20transfer" title=" turbulent heat transfer"> turbulent heat transfer</a> </p> <a href="https://publications.waset.org/abstracts/60051/assessment-of-modern-rans-models-for-the-c3x-vane-film-cooling-prediction" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/60051.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">420</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">17002</span> Effect of Inclination Angle on Productivity of a Direct Contact Membrane Distillation (Dcmd) Process</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Adnan%20Alhathal%20Alanezi">Adnan Alhathal Alanezi</a>, <a href="https://publications.waset.org/abstracts/search?q=Alanood%20A.%20Alsarayreh"> Alanood A. Alsarayreh</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A direct contact membrane distillation (DCMD) system was modeled using various angles for the membrane unit and a Reynolds number range of 500 to 2000 in this numerical analysis. The Navier-Stokes, energy, and species transport equations were used to create a two-dimensional model. The finite volume method was used to solve the governing equations (FVM). The results showed that as the Reynolds number grows up to 1500, the heat transfer coefficient increases for all membrane angles except the 60ᵒ inclination angle. Additionally, increasing the membrane angle to 90ᵒreduces the exit influence while increasing heat transfer. According to these data, a membrane with a 90o inclination angle (also known as a vertical membrane) and a Reynolds number of 2000 might have the smallest temperature differential. Similarly, decreasing the inclination angle of the membrane keeps the temperature difference constant between Reynolds numbers 1000 and 2000; however, between Reynolds numbers 500 and 1000, the temperature difference decreases dramatically. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=direct%20contact%20membrane%20distillation" title="direct contact membrane distillation">direct contact membrane distillation</a>, <a href="https://publications.waset.org/abstracts/search?q=membrane%20inclination%20angle" title=" membrane inclination angle"> membrane inclination angle</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20and%20mass%20%20transfer" title=" heat and mass transfer"> heat and mass transfer</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/151283/effect-of-inclination-angle-on-productivity-of-a-direct-contact-membrane-distillation-dcmd-process" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/151283.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">120</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">17001</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">17000</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">16999</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">16998</span> Study the Effect of Roughness on the Higher Order Moment to Extract Information about the Turbulent Flow Structure in an Open Channel Flow</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Md%20Abdullah%20Al%20Faruque">Md Abdullah Al Faruque</a>, <a href="https://publications.waset.org/abstracts/search?q=Ram%20Balachandar"> Ram Balachandar</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The present study was carried out to understand the extent of effect of roughness and Reynolds number in open channel flow (OCF). To this extent, four different types of bed surface conditions consisting smooth, distributed roughness, continuous roughness, natural sand bed and two different Reynolds number for each bed surfaces were adopted in this study. Particular attention was given on mean velocity, turbulence intensity, Reynolds shear stress, correlation, higher order moments and quadrant analysis. Further, the extent of influence of roughness and Reynolds number in the depth-wise direction also studied. Increasing Reynolds shear stress near rough beds are noticed due to arrays of discrete roughness elements and flow over these elements generating a series of wakes which contributes to the generation of significantly higher Reynolds shear stress. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bed%20roughness" title="bed roughness">bed roughness</a>, <a href="https://publications.waset.org/abstracts/search?q=ejection%20and%20sweep" title=" ejection and sweep"> ejection and sweep</a>, <a href="https://publications.waset.org/abstracts/search?q=open%20channel%20flow" title=" open channel flow"> open channel flow</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20shear%20stress" title=" Reynolds shear stress"> Reynolds shear stress</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulent%20boundary%20layer" title=" turbulent boundary layer"> turbulent boundary layer</a>, <a href="https://publications.waset.org/abstracts/search?q=velocity%20triple%20product" title=" velocity triple product"> velocity triple product</a> </p> <a href="https://publications.waset.org/abstracts/45772/study-the-effect-of-roughness-on-the-higher-order-moment-to-extract-information-about-the-turbulent-flow-structure-in-an-open-channel-flow" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/45772.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">258</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">16997</span> Experimental and Computational Investigation of Flow Field and Thermal Behavior of a Mechanical Seal</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Hossein%20Shokouhmand">Hossein Shokouhmand</a>, <a href="https://publications.waset.org/abstracts/search?q=Masoomeh%20Shadab"> Masoomeh Shadab</a>, <a href="https://publications.waset.org/abstracts/search?q=Rohallah%20Torabi"> Rohallah Torabi</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Turbulent flow inside the seal chamber of a pump operating at nearly high Reynolds number is investigated. A comparison of a 3-D computational model for flow and thermal analysis of a mechanical seal with experimental thermal results is presented. The computational model adequately predicts the flow field in the seal chamber and thermal characteristics with the rotating and stationary rings and the twister flow around the seal parts by solving N-S and energy equations in ANSYS-CFX software. The Reynolds stress model (RSM) is applied as a turbulence model for this purpose. Experimental work is discussed which quantifies the temperature of five different points of the working fluid in chamber, mass flow at inlet and the fluid pressure at inlet and outlet. Experimental measurements are combined with computational modeling to obtain local and average heat transfer characteristics. Numerical results of three cases including different flush rates are reported. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=mechanical%20seal" title="mechanical seal">mechanical seal</a>, <a href="https://publications.waset.org/abstracts/search?q=CFD_CFX" title=" CFD_CFX"> CFD_CFX</a>, <a href="https://publications.waset.org/abstracts/search?q=reynolds%20stress%20model" title=" reynolds stress model"> reynolds stress model</a>, <a href="https://publications.waset.org/abstracts/search?q=flow%20field" title=" flow field"> flow field</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20transfer%20analysis" title=" heat transfer analysis"> heat transfer analysis</a>, <a href="https://publications.waset.org/abstracts/search?q=stream%20line" title=" stream line"> stream line</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20transfer%20coefficient" title=" heat transfer coefficient"> heat transfer coefficient</a>, <a href="https://publications.waset.org/abstracts/search?q=heat%20flux" title=" heat flux"> heat flux</a>, <a href="https://publications.waset.org/abstracts/search?q=nusselt" title=" nusselt"> nusselt</a> </p> <a href="https://publications.waset.org/abstracts/2394/experimental-and-computational-investigation-of-flow-field-and-thermal-behavior-of-a-mechanical-seal" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/2394.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">440</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">16996</span> Numerical Investigation of Heat Transfer in a Channel with Delta Winglet Vortex Generators at Different Reynolds Numbers</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=N.%20K.%20Singh">N. K. Singh</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this study the augmentation of heat transfer in a rectangular channel with triangular vortex generators is evaluated. The span wise averaged Nusselt number, mean temperature and total heat flux are compared with and without vortex generators in the channel at a blade angle of 30° for Reynolds numbers 800, 1200, 1600, and 2000. The use of vortex generators increases the span wise averaged Nusselt number compared to the case without vortex generators considerably. At a particular blade angle, increasing the Reynolds number results in an enhancement in the overall performance and span wise averaged Nusselt number was found to be greater at particular location for larger Reynolds number. The total heat flux from the bottom wall with vortex generators was found to be greater than that without vortex generators and the difference increases with increase in Reynolds number. <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=channel%20with%20vortex%20generators" title=" channel with vortex generators"> channel with vortex generators</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=effect%20of%20Reynolds%20number%20on%20heat%20transfer" title=" effect of Reynolds number on heat transfer"> effect of Reynolds number on heat transfer</a> </p> <a href="https://publications.waset.org/abstracts/3475/numerical-investigation-of-heat-transfer-in-a-channel-with-delta-winglet-vortex-generators-at-different-reynolds-numbers" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/3475.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">331</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">16995</span> Three-Dimensional Numerical Simulation of Drops Suspended in Poiseuille Flow: Effect of Reynolds Number</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=A.%20Nourbakhsh">A. Nourbakhsh</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A finite difference/front tracking method is used to study the motion of three-dimensional deformable drops suspended in plane Poiseuille flow at non-zero Reynolds numbers. A parallel version of the code was used to study the behavior of suspension on a reasonable grid resolution (grids). The viscosity and density of drops are assumed to be equal to that of the suspending medium. The effect of the Reynolds number is studied in detail. It is found that drops with small deformation behave like rigid particles and migrate to an equilibrium position about half way between the wall and the center line (the Segre-Silberberg effect). However, for highly deformable drops there is a tendency for drops to migrate to the middle of the channel, and the maximum concentration occurs at the center line. The effective viscosity of suspension and the fluctuation energy of the flow across the channel increases with the Reynolds number of the flow. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=suspensions" title="suspensions">suspensions</a>, <a href="https://publications.waset.org/abstracts/search?q=Poiseuille%20flow" title=" Poiseuille flow"> Poiseuille flow</a>, <a href="https://publications.waset.org/abstracts/search?q=effective%20viscosity" title=" effective viscosity"> effective viscosity</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/11946/three-dimensional-numerical-simulation-of-drops-suspended-in-poiseuille-flow-effect-of-reynolds-number" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/11946.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">16994</span> Behaviours of Energy Spectrum at Low Reynolds Numbers in Grid Turbulence</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Md%20Kamruzzaman">Md Kamruzzaman</a>, <a href="https://publications.waset.org/abstracts/search?q=Lyazid%20Djenidi"> Lyazid Djenidi</a>, <a href="https://publications.waset.org/abstracts/search?q=R.%20A.%20Antonia"> R. A. Antonia</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper reports an experimental investigation of the energy spectrum of turbulent velocity fields at low Reynolds numbers ( Rλ ) in grid turbulence. Hot wire measurements are carried out in grid turbulence with subjected to a 1.36:1 contraction of the wind tunnel. Three different grids are used: (i) large square perforated grid (mesh size 43.75 mm), (ii) small square perforated grid (mesh size 14 and (iii) woven mesh grid (mesh size 5mm). The results indicate that the energy spectrum at small Rλ does not follow Kolmogorov’s universal scaling. It is further found that the critical Reynolds number,Rλ,ϲ below which the scaling breaks down is around 25. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=energy%20spectrum" title="energy spectrum">energy spectrum</a>, <a href="https://publications.waset.org/abstracts/search?q=Taylor%20microscale" title=" Taylor microscale"> Taylor microscale</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20number" title=" Reynolds number"> Reynolds number</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulent%20kinetic%20energy" title=" turbulent kinetic energy"> turbulent kinetic energy</a>, <a href="https://publications.waset.org/abstracts/search?q=decay%20exponent" title=" decay exponent "> decay exponent </a> </p> <a href="https://publications.waset.org/abstracts/1417/behaviours-of-energy-spectrum-at-low-reynolds-numbers-in-grid-turbulence" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/1417.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">292</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">16993</span> Aerodynamic Performance of a Pitching Bio-Inspired Corrugated Airfoil</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Hadi%20Zarafshani">Hadi Zarafshani</a>, <a href="https://publications.waset.org/abstracts/search?q=Shidvash%20Vakilipour"> Shidvash Vakilipour</a>, <a href="https://publications.waset.org/abstracts/search?q=Shahin%20Teimori"> Shahin Teimori</a>, <a href="https://publications.waset.org/abstracts/search?q=Sara%20Barati"> Sara Barati</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In the present study, the aerodynamic performance of a rigid two-dimensional pitching bio-inspired corrugate airfoil was numerically investigated at Reynolds number of 14000. The Open Field Operations And Manipulations (OpenFOAM) computational fluid dynamic tool is used to solve flow governing equations numerically. The k-ω SST turbulence model with low Reynolds correction (k-ω SST LRC) and the pimpleDyMFOAM solver are utilized to simulate the flow field around pitching bio-airfoil. The lift and drag coefficients of the airfoil are calculated at reduced frequencies k=1.24-4.96 and the angular amplitude of A=5<sup>°</sup>-20<sup>°</sup>. Results show that in a fixed reduced frequency, the absolute value of the sectional lift and drag coefficients increase with increasing pitching amplitude. In a fixed angular amplitude, the absolute value of the lift and drag coefficients increase as the pitching reduced frequency increases. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bio-inspired%20pitching%20airfoils" title="bio-inspired pitching airfoils">bio-inspired pitching airfoils</a>, <a href="https://publications.waset.org/abstracts/search?q=OpenFOAM" title=" OpenFOAM"> OpenFOAM</a>, <a href="https://publications.waset.org/abstracts/search?q=low%20Reynolds%20k-%CF%89%20SST%20model" title=" low Reynolds k-ω SST model"> low Reynolds k-ω SST model</a>, <a href="https://publications.waset.org/abstracts/search?q=lift%20and%20drag%20coefficients" title=" lift and drag coefficients"> lift and drag coefficients</a> </p> <a href="https://publications.waset.org/abstracts/87363/aerodynamic-performance-of-a-pitching-bio-inspired-corrugated-airfoil" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/87363.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">190</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">16992</span> CFD Simulation for Thermo-Hydraulic Performance V-Shaped Discrete Ribs on the Absorber Plate of Solar Air Heater</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=J.%20L.%20Bhagoria">J. L. Bhagoria</a>, <a href="https://publications.waset.org/abstracts/search?q=Ajeet%20Kumar%20Giri"> Ajeet Kumar Giri</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A computational investigation of various flow characteristics with artificial roughness in the form of V-types discrete ribs, heated wall of rectangular duct for turbulent flow with Reynolds number range (3800-15000) and p/e (5 to 12) has been carried out with k-e turbulence model is selected by comparing the predictions of different turbulence models with experimental results available in literature. The current study evaluates thermal performance behavior, heat transfer and fluid flow behavior in a v shaped duct with discrete roughened ribs mounted on one of the principal wall (solar plate) by computational fluid dynamics software (Fluent 6.3.26 Solver). In this study, CFD has been carried out through designing 3-demensional model of experimental solar air heater model analysis has been used to perform a numerical simulation to enhance turbulent heat transfer and Reynolds-Averaged Navier–Stokes analysis is used as a numerical technique and the k-epsilon model with near-wall treatment as a turbulent model. The thermal efficiency enhancement because of selected roughness is found to be 16-24%. The result predicts a significant enhancement of heat transfer as compared to that of for a smooth surface with different P’ and various range of Reynolds number. <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=solar%20collector" title=" solar collector"> solar collector</a>, <a href="https://publications.waset.org/abstracts/search?q=airheater" title=" airheater"> airheater</a>, <a href="https://publications.waset.org/abstracts/search?q=thermal%20efficiency" title=" thermal efficiency"> thermal efficiency</a> </p> <a href="https://publications.waset.org/abstracts/47346/cfd-simulation-for-thermo-hydraulic-performance-v-shaped-discrete-ribs-on-the-absorber-plate-of-solar-air-heater" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/47346.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">290</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">16991</span> Numerical Investigation of Flow Behaviour Across a Trapezoidal Bluff Body at Low Reynolds Number</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Zaaraoui%20Abdelkader">Zaaraoui Abdelkader</a>, <a href="https://publications.waset.org/abstracts/search?q=Kerfah%20Rabeh"> Kerfah Rabeh</a>, <a href="https://publications.waset.org/abstracts/search?q=Noura%20Belkheir"> Noura Belkheir</a>, <a href="https://publications.waset.org/abstracts/search?q=Matene%20Elhacene"> Matene Elhacene</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The trapezoidal bluff body is a typical configuration of vortex shedding bodies. The aim of this work is to study flow behaviour over a trapezoidal cylinder at low Reynolds number. The geometry was constructed from a prototype device for measuring the volumetric flow-rate by counting vortices. Simulations were run for this geometry under steady and unsteady flow conditions using finite volume discretization. Laminar flow was investigated in this model with rigid walls and homogeneous incompressible Newtonian fluid. Calculations were performed for Reynolds number range 5 ≤ Re ≤ 180 and several flow parameters were documented. The present computations are in good agreement with the experimental observations and the numerical calculations by several investigators. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bluff%20body" title="bluff body">bluff body</a>, <a href="https://publications.waset.org/abstracts/search?q=confined%20flow" title=" confined flow"> confined flow</a>, <a href="https://publications.waset.org/abstracts/search?q=numerical%20calculations" title=" numerical calculations"> numerical calculations</a>, <a href="https://publications.waset.org/abstracts/search?q=steady%20and%20unsteady%20flow" title=" steady and unsteady flow"> steady and unsteady flow</a>, <a href="https://publications.waset.org/abstracts/search?q=vortex%20shedding%20flow%20meter" title=" vortex shedding flow meter"> vortex shedding flow meter</a> </p> <a href="https://publications.waset.org/abstracts/54144/numerical-investigation-of-flow-behaviour-across-a-trapezoidal-bluff-body-at-low-reynolds-number" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/54144.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">287</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">16990</span> An investigation of Leading Edge and Trailing Edge Corrugation for Low Reynolds Number Application</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Syed%20Hassan%20Raza%20Shah">Syed Hassan Raza Shah</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohammad%20Mohammad%20Ali"> Mohammad Mohammad Ali</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The flow over a smoothly profiled airfoil at a low Reynolds number is highly susceptible to separate even at a very low angle of attack. An investigation was made to study the effect of leading-edge and trailing-edge corrugation with the spanwise change in the ridges resulted due to the change in the chord length for an infinite wing. The wind tunnel results using NACA0018 wings revealed that leading and trailing edge corrugation did not have any benefit in terms of aerodynamic efficiency or delayed stall. The leading edge and trailing edge corrugation didn't change the lift curve slope, with the leading edge corrugation wing stalling first in the range of Reynolds number of 50,000 to 125,000. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=leading%20and%20trailing%20edge%20corrugations" title="leading and trailing edge corrugations">leading and trailing edge corrugations</a>, <a href="https://publications.waset.org/abstracts/search?q=low%20reynolds%20number" title=" low reynolds number"> low reynolds number</a>, <a href="https://publications.waset.org/abstracts/search?q=wind%20tunnel%20testing" title=" wind tunnel testing"> wind tunnel testing</a>, <a href="https://publications.waset.org/abstracts/search?q=NACA0018" title=" NACA0018"> NACA0018</a> </p> <a href="https://publications.waset.org/abstracts/141121/an-investigation-of-leading-edge-and-trailing-edge-corrugation-for-low-reynolds-number-application" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/141121.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">291</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">16989</span> Numerical Investigation of the Effect of Geometrical Shape of Plate Heat Exchangers on Heat Transfer Efficiency</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Hamed%20Sanei">Hamed Sanei</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohammad%20Bagher%20Ayani"> Mohammad Bagher Ayani</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Optimizations of Plate Heat Exchangers (PHS) have received great attention in the past decade. In this study, heat transfer and pressure drop coefficients are compared for rectangular and circular PHS employing numerical simulations. Plates are designed to have equivalent areas. Simulations were implemented to investigate the efficiency of PHSs considering heat transfer, friction factor and pressure drop. Amount of heat transfer and pressure drop was obtained for different range of Reynolds numbers. These two parameters were compared with aim of <em>F</em> "weighting factor correlation". In this comparison, the minimum amount of F indicates higher efficiency. Results reveal that the <em>F</em> value for rectangular shape is less than circular plate, and hence using rectangular shape of PHS is more efficient than circular one. It was observed that, the amount of friction factor is correlated to the Reynolds numbers, such that friction factor decreased in both rectangular and circular plates with an increase in Reynolds number. Furthermore, such simulations revealed that the amount of heat transfer in rectangular plate is more than circular plate for different range of Reynolds numbers. The difference is more distinct for higher Reynolds number. However, amount of pressure drop in circular plate is less than rectangular plate for the same range of Reynolds numbers which is considered as a negative point for rectangular plate efficiency. It can be concluded that, while rectangular PHSs occupy more space than circular plate, the efficiency of rectangular plate is higher. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=Chevron%20corrugated%20plate%20heat%20exchanger" title="Chevron corrugated plate heat exchanger">Chevron corrugated plate heat exchanger</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=friction%20factor" title=" friction factor"> friction factor</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20numbers" title=" Reynolds numbers"> Reynolds numbers</a> </p> <a href="https://publications.waset.org/abstracts/47194/numerical-investigation-of-the-effect-of-geometrical-shape-of-plate-heat-exchangers-on-heat-transfer-efficiency" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/47194.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">300</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">16988</span> Efficient Numerical Simulation for LDC</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Badr%20Alkahtani">Badr Alkahtani</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this poster, numerical solutions of two-dimensional and three-dimensional lid driven cavity are presented by solving the steady Navier-Stokes equations at high Reynolds numbers where it becomes difficult. Lid driven cavity is where the a fluid contained in a cube and the upper wall is moving. In two dimensions, we use the streamfunction-vorticity formulation to solve the problem in a square domain. A numerical method is employed to discretize the problem in the x and y directions with a spectral collocation method. The problem is coded in the MATLAB programming environment. Solutions at high Reynolds numbers are obtained up to Re=20000 on a fine grid of 131 * 131. Also in this presentation, the numerical solutions for the three-dimensional lid-driven cavity problem are obtained by solving the velocity-vorticity formulation of the Navier-Stokes equations (which is the first time that this has been simulated with special boundary conditions) for various Reynolds numbers. A spectral collocation method is employed to discretize the y and z directions and a finite difference method is used to discretize the x direction. Numerical solutions are obtained for Reynolds number up to 200. , The work prepared here is to show the efficiency of methods used to simulate the physical problem where accurate simulations of lid driven cavity are obtained at high Reynolds number as mentioned above. The result for the two dimensional problem is far from the previous researcher result. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=lid%20driven%20cavity" title="lid driven cavity">lid driven cavity</a>, <a href="https://publications.waset.org/abstracts/search?q=navier-stokes" title=" navier-stokes"> navier-stokes</a>, <a href="https://publications.waset.org/abstracts/search?q=simulation" title=" simulation"> simulation</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/20652/efficient-numerical-simulation-for-ldc" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/20652.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">715</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">16987</span> Numerical Study of an Impinging Jet in a Coflow Stream</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Rim%20Ben%20Kalifa">Rim Ben Kalifa</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=Herv%C3%A9%20Bournot"> Hervé 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> The present study treats different phenomena taking place in a configuration of air jet impinging on a flat surface in a coflow stream. A Computational Fluid Dynamics study is performed using the Reynolds-averaged Navier–Stokes equations by means of the Reynolds Stress Model (RSM) second order turbulent closure model. The results include mean and turbulent velocities and quantify the large effects of the coflow stream on an impinging air jet. The study of the jet in a no-directed coflow stream shows the presence of a phenomenon of recirculation near the flat plate. The influence of the coflow velocity ratio on the behavior of an impinging plane jet was also numerically investigated. The coflow stream imposed noticeable restrictions on the spreading of the impinging jet. The results show that the coflow stream decreases considerably the entrainment of air jet. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=turbulent%20jet" title="turbulent jet">turbulent jet</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulence%20models" title=" turbulence models"> turbulence models</a>, <a href="https://publications.waset.org/abstracts/search?q=coflow%20stream" title=" coflow stream"> coflow stream</a>, <a href="https://publications.waset.org/abstracts/search?q=velocity%20ratio" title=" velocity ratio"> velocity ratio</a> </p> <a href="https://publications.waset.org/abstracts/42629/numerical-study-of-an-impinging-jet-in-a-coflow-stream" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/42629.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">238</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">16986</span> Experimental Study of Heat Transfer in Pulsation Mist Flow in Rectanglar Duct Partially Filled with a Porous Medium</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Hosein%20Shokoohmand">Hosein Shokoohmand</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohamad%20Esmaeil%20Jomeh"> Mohamad Esmaeil Jomeh</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The present thesis studies the effect of different factors such as frequency of oscillatory flow, change in constant wall heat flux and two-phase current state, on heat transfer in a pipe in presence of porous medium. In this experimental study is conducted for Reynolds numbers in a range of Re=850 to Re=10000 and oscillatory frequencies of 5, 20, 10, 30 and 40 Hz with constant heat flux of 585 w/m2 and 819 w/m2. The results indicate that increase in oscillation frequency in higher frequencies for heat flux of 585 w/m2 leads to an increase in heat transfer; however, in the rest of tests it results in a heat transfer decrease. Increasing Reynolds number in a pulsation mist flow causes an increase in average Nusselt number values. The effect of oscillation frequencies in a pulsation mist flow for different Reynolds numbers has revealed different results, in a way that for some Reynolds numbers an increase of frequency has led to a heat transfer decrease. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20numbers" title="Reynolds numbers">Reynolds numbers</a>, <a href="https://publications.waset.org/abstracts/search?q=frequency%20of%20oscillatory%20flow" title=" frequency of oscillatory flow"> frequency of oscillatory flow</a>, <a href="https://publications.waset.org/abstracts/search?q=constant%20heat%20flux" title=" constant heat flux"> constant heat flux</a>, <a href="https://publications.waset.org/abstracts/search?q=mist%20flow" title=" mist flow "> mist flow </a> </p> <a href="https://publications.waset.org/abstracts/31780/experimental-study-of-heat-transfer-in-pulsation-mist-flow-in-rectanglar-duct-partially-filled-with-a-porous-medium" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/31780.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">494</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">16985</span> Calculating of the Heat Exchange in a Rotating Pipe: Application to the Cooling of Turbine Blades</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=A.%20Miloud">A. Miloud</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this work, the results of numerical simulations of the turbulent flow with 3D heat transfer are presented for the case of two U-shaped channels and rotating rectangular section. The purpose of this investigation was to study the effect of the corrugated walls of the heated portion on the improved cooling, in particular the influence of the wavelength. The calculations were performed for a Reynolds number ranging from 10 000 to 100 000, two values of the number of rotation (Ro = 0.0 to 0.14) and a ratio of the restricted density to 0.13. In these simulations, ANSYS FLUENT code was used to solve the Reynolds equations expressing relations between different fields averaged variables over time. Model performance k-omega SST model and RSM are evaluated through a comparison of the numerical results for each model and the experimental and numerical data available. In this work, detailed average temperature predictions, the scope of the secondary flow and distributions of local Nusselt are presented. It turns out that the corrugated configuration further urges the heat exchange provided to reduce the velocity of the coolant inside the channel. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=cooling%20blades" title="cooling blades">cooling blades</a>, <a href="https://publications.waset.org/abstracts/search?q=corrugated%20walls" title=" corrugated walls"> corrugated walls</a>, <a href="https://publications.waset.org/abstracts/search?q=model%20k-omega%20SST%20and%20RSM" title=" model k-omega SST and RSM"> model k-omega SST and RSM</a>, <a href="https://publications.waset.org/abstracts/search?q=fluent%20code" title=" fluent code"> fluent code</a>, <a href="https://publications.waset.org/abstracts/search?q=rotation%20effect" title=" rotation effect"> rotation effect</a> </p> <a href="https://publications.waset.org/abstracts/45617/calculating-of-the-heat-exchange-in-a-rotating-pipe-application-to-the-cooling-of-turbine-blades" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/45617.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">251</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">16984</span> Experimental Investigation of Boundary Layer Transition on Rotating Cones in Axial Flow in 0 and 35 Degrees Angle of Attack</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ali%20Kargar">Ali Kargar</a>, <a href="https://publications.waset.org/abstracts/search?q=Kamyar%20Mansour"> Kamyar Mansour</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this paper, experimental results of using hot wire anemometer and smoke visualization are presented. The results obtained on the hot wire anemometer for critical Reynolds number and transitional Reynolds number are compared by previous results. Excellent agreement is found for the transitional Reynolds number. The results for the transitional Reynolds number are also compared by previous linear stability results. The results of the smoke visualization clearly show the cross flow vortices which arise in the transition process from a laminar to a turbulent flow. A non-zero angle of attack is also considered. We compare our results by linear stability theory which was done by Garret et. Al (2007). We just emphasis, Also the visualization and hot wire anemometer results have been compared graphically. The goal in this paper is to check reliability of using hot wire anemometer and smoke visualization in transition problems and check reliability of linear stability theory for this case and compare our results with some trusty experimental works. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=transitional%20reynolds%20number" title="transitional reynolds number">transitional reynolds number</a>, <a href="https://publications.waset.org/abstracts/search?q=wind%20tunnel" title=" wind tunnel"> wind tunnel</a>, <a href="https://publications.waset.org/abstracts/search?q=rotating%20cone" title=" rotating cone"> rotating cone</a>, <a href="https://publications.waset.org/abstracts/search?q=smoke%20visualization" title=" smoke visualization"> smoke visualization</a> </p> <a href="https://publications.waset.org/abstracts/34675/experimental-investigation-of-boundary-layer-transition-on-rotating-cones-in-axial-flow-in-0-and-35-degrees-angle-of-attack" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/34675.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">307</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">16983</span> Turbulence Measurement Over Rough and Smooth Bed in Open Channel Flow</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Kirti%20Singh">Kirti Singh</a>, <a href="https://publications.waset.org/abstracts/search?q=Kesheo%20Prasad"> Kesheo Prasad</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A 3D Acoustic Doppler velocimeter was used in the current investigation to quantify the mean and turbulence characteristics in non-uniform open-channel flows. Results are obtained from studies done in the laboratory, analysing the behavior of sand particles under turbulent open channel flow conditions flowing through rough, porous beds. Data obtained from ADV is used to calculate turbulent flow characteristics, Reynolds stresses and turbulent kinetic energy. Theoretical formulations for the distribution of Reynolds stress and the vertical velocity have been constructed using the Reynolds equation and the continuity equation of 2D open-channel flow. The measured Reynolds stress profile and the vertical velocity are comparable with the derived expressions. This study uses the Navier-Stokes equations for analysing the behavior of the vertical velocity profile in the dominant region of full-fledged turbulent flows in open channels, and it gives a new origination of the profile. For both wide and narrow open channels, this origination can estimate the time-averaged primary velocity in the turbulent boundary layer's outer region. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=turbulence" title="turbulence">turbulence</a>, <a href="https://publications.waset.org/abstracts/search?q=bed%20roughness" title=" bed roughness"> bed roughness</a>, <a href="https://publications.waset.org/abstracts/search?q=logarithmic%20law" title=" logarithmic law"> logarithmic law</a>, <a href="https://publications.waset.org/abstracts/search?q=shear%20stress%20correlations" title=" shear stress correlations"> shear stress correlations</a>, <a href="https://publications.waset.org/abstracts/search?q=ADV" title=" ADV"> ADV</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20shear%20stress" title=" Reynolds shear stress"> Reynolds shear stress</a> </p> <a href="https://publications.waset.org/abstracts/159300/turbulence-measurement-over-rough-and-smooth-bed-in-open-channel-flow" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/159300.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">107</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">16982</span> Numerical Investigation of Turbulent Flow Control by Suction and Injection on a Subsonic NACA23012 Airfoil by Proper Orthogonal Decomposition Analysis and Perturbed Reynolds Averaged Navier‐Stokes Equations</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Azam%20Zare">Azam Zare</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Separation flow control for performance enhancement over airfoils at high incidence angle has become an increasingly important topic. This work details the characteristics of an efficient feedback control of the turbulent subsonic flow over NACA23012 airfoil using forced reduced‐order model based on the proper orthogonal decomposition/Galerkin projection and perturbation method on the compressible Reynolds Averaged Navier‐Stokes equations. The forced reduced‐order model is used in the optimal control of the turbulent separated flow over a NACA23012 airfoil at Mach number of 0.2, Reynolds number of 5×106, and high incidence angle of 24° using blowing/suction controlling jets. The Spallart-Almaras turbulence model is implemented for high Reynolds number calculations. The main shortcoming of the POD/Galerkin projection on flow equations for controlling purposes is that the blowing/suction controlling jet velocity does not show up explicitly in the resulting reduced order model. Combining perturbation method and POD/Galerkin projection on flow equations introduce a forced reduced‐order model that can predict the time-varying influence of the blowing/suction controlling jet velocity. An optimal control theory based on forced reduced‐order system is used to design a control law for a nonlinear reduced‐order model, which attempts to minimize the vorticity content in the turbulent flow field over NACA23012 airfoil. Numerical simulations were performed to help understand the behavior of the controlled suction jet at 12% to 18% chord from leading edge and a pair of blowing/suction jets at 15% to 18% and 24% to 30% chord from leading edge, respectively. Analysis of streamline profiles indicates that the blowing/suction jets are efficient in removing separation bubbles and increasing the lift coefficient up to 22%, while the perturbation method can predict the flow field in an accurate Manner. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=flow%20control" title="flow control">flow control</a>, <a href="https://publications.waset.org/abstracts/search?q=POD" title=" POD"> POD</a>, <a href="https://publications.waset.org/abstracts/search?q=Galerkin%20projection" title=" Galerkin projection"> Galerkin projection</a>, <a href="https://publications.waset.org/abstracts/search?q=separation" title=" separation"> separation</a> </p> <a href="https://publications.waset.org/abstracts/95962/numerical-investigation-of-turbulent-flow-control-by-suction-and-injection-on-a-subsonic-naca23012-airfoil-by-proper-orthogonal-decomposition-analysis-and-perturbed-reynolds-averaged-navierstokes-equations" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/95962.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">149</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">16981</span> CFD Investigation on Heat Transfer and Friction Characteristics of Rib Roughened Evacuated Tube Collector Solar Air Heater</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Mohit%20Singla">Mohit Singla</a>, <a href="https://publications.waset.org/abstracts/search?q=Vishavjeet%20Singh%20Hans"> Vishavjeet Singh Hans</a>, <a href="https://publications.waset.org/abstracts/search?q=Sukhmeet%20Singh"> Sukhmeet Singh</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Heat transfer and friction characteristics of evacuated tube collector solar air heater artificially roughened with periodic circular rib of uniform cross-section were investigated. The present investigation was carried out in ANSYS Fluent 15.0 to study the impact of roughness geometry parameters, i.e. relative roughness pitch (P/e) of 8 and relative roughness height (e/Dh) of 0.064 and flow parameters, i.e. Reynolds number range of 2500-8000 on Nusselt number and friction factor. RNG k-ε with enhanced wall treatment turbulence model was selected for analysis. The results obtained for roughened evacuated tube collector has been compared with smooth evacuated tube collector for the similar flow conditions. With the increment in Reynolds number from 2500 to 8000, Nusselt number augments while friction factor decreases. Maximum enhancement ratio of Nusselt number and friction factor was 1.71 and 2.7 respectively, obtained at Reynolds number value of 8000. The value of thermo-hydraulic performance parameter was varied between 1.18 - 1.23 for the entire range of Reynolds number, indicates the advantage to use the roughened evacuated tube collector over smooth evacuated tube collector in solar air heater. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=artificial%20roughness" title="artificial roughness">artificial roughness</a>, <a href="https://publications.waset.org/abstracts/search?q=evacuated%20tube%20collector" title=" evacuated tube collector"> evacuated tube collector</a>, <a href="https://publications.waset.org/abstracts/search?q=friction%20factor" title=" friction factor"> friction factor</a>, <a href="https://publications.waset.org/abstracts/search?q=Nusselt%20number" title=" Nusselt number"> Nusselt number</a> </p> <a href="https://publications.waset.org/abstracts/124728/cfd-investigation-on-heat-transfer-and-friction-characteristics-of-rib-roughened-evacuated-tube-collector-solar-air-heater" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/124728.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">162</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">16980</span> Effect of Reynolds Number on Wall-normal Turbulence Intensity in a Smooth and Rough Open Channel Using both Outer and Inner Scaling</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Md%20Abdullah%20Al%20Faruque">Md Abdullah Al Faruque</a>, <a href="https://publications.waset.org/abstracts/search?q=Ram%20Balachandar"> Ram Balachandar</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Sudden change of bed condition is frequent in open channel flow. Change of bed condition affects the turbulence characteristics in both streamwise and wall-normal direction. Understanding the turbulence intensity in open channel flow is of vital importance to the modeling of sediment transport and resuspension, bed formation, entrainment, and the exchange of energy and momentum. A comprehensive study was carried out to understand the extent of the effect of Reynolds number and bed roughness on different turbulence characteristics in an open channel flow. Four different bed conditions (impervious smooth bed, impervious continuous rough bed, pervious rough sand bed, and impervious distributed roughness) and two different Reynolds numbers were adopted for this cause. The effect of bed roughness on different turbulence characteristics is seen to be prevalent for most of the flow depth. Effect of Reynolds number on different turbulence characteristics is also evident for flow over different bed, but the extent varies on bed condition. Although the same sand grain is used to create the different rough bed conditions, the difference in turbulence characteristics is an indication that specific geometry of the roughness has an influence on turbulence characteristics. Roughness increases the contribution of the extreme turbulent events which produces very large instantaneous Reynolds shear stress and can potentially influence the sediment transport, resuspension of pollutant from bed and alter the nutrient composition, which eventually affect the sustainability of benthic organisms. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=open%20channel%20flow" title="open channel flow">open channel flow</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20Number" title=" Reynolds Number"> Reynolds Number</a>, <a href="https://publications.waset.org/abstracts/search?q=roughness" title=" roughness"> roughness</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulence" title=" turbulence"> turbulence</a> </p> <a href="https://publications.waset.org/abstracts/54441/effect-of-reynolds-number-on-wall-normal-turbulence-intensity-in-a-smooth-and-rough-open-channel-using-both-outer-and-inner-scaling" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/54441.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">400</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">16979</span> Experimental Investigation of S822 and S823 Wind Turbine Airfoils Wake</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Amir%20B.%20Khoshnevis">Amir B. Khoshnevis</a>, <a href="https://publications.waset.org/abstracts/search?q=Morteza%20Mirhosseini"> Morteza Mirhosseini</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The paper deals with a sub-part of an extensive research program on the wake survey method in various Reynolds numbers and angles of attack. This research experimentally investigates the wake flow characteristics behind S823 and S822 airfoils in which designed for small wind turbines. Velocity measurements determined by using hot-wire anemometer. Data acquired in the wake of the airfoil at locations(c is the chord length): 0.01c - 3c. Reynolds number increased due to increase of free stream velocity. Results showed that mean velocity profiles depend on the angle of attack and location of data collections. Data acquired at the low Reynolds numbers (smaller than 10^5). Effects of Reynolds numbers on the mean velocity profiles are more significant in near locations the trailing edge and these effects decrease by taking distance from trailing edge toward downstream. Mean velocity profiles region increased by increasing the angle of attack, except for 7°, and also the maximum velocity deficit (velocity defect) increased. The difference of mean velocity in and out of the wake decreased by taking distance from trailing edge, and mean velocity profile become wider and more uniform. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=angle%20of%20attack" title="angle of attack">angle of attack</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20number" title=" Reynolds number"> Reynolds number</a>, <a href="https://publications.waset.org/abstracts/search?q=velocity%20deficit" title=" velocity deficit"> velocity deficit</a>, <a href="https://publications.waset.org/abstracts/search?q=separation" title=" separation"> separation</a> </p> <a href="https://publications.waset.org/abstracts/36863/experimental-investigation-of-s822-and-s823-wind-turbine-airfoils-wake" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/36863.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">377</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">16978</span> Flow-Control Effectiveness of Convergent Surface Indentations on an Aerofoil at Low Reynolds Numbers</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Neel%20K.%20Shah">Neel K. Shah</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Passive flow control on aerofoils has largely been achieved through the use of protrusions such as vane-type vortex generators. Consequently, innovative flow-control concepts should be explored in an effort to improve current component performance. Therefore, experimental research has been performed at The University of Manchester to evaluate the flow-control effectiveness of a vortex generator made in the form of a surface indentation. The surface indentation has a trapezoidal planform. A spanwise array of indentations has been applied in a convergent orientation around the maximum-thickness location of the upper surface of a NACA-0015 aerofoil. The aerofoil has been tested in a two-dimensional set-up in a low-speed wind tunnel at an angle of attack (AoA) of 3° and a chord-based Reynolds number (Re) of ~2.7 x 105. The baseline model has been found to suffer from a laminar separation bubble at low AoA. The application of the indentations at 3° AoA has considerably shortened the separation bubble. The indentations achieve this by shedding up-flow pairs of streamwise vortices. Despite the considerable reduction in bubble length, the increase in leading-edge suction due to the shorter bubble is limited by the removal of surface curvature and blockage (increase in surface pressure) caused locally by the convergent indentations. Furthermore, the up-flow region of the vortices, which locally weakens the pressure recovery around the trailing edge of the aerofoil by thickening the boundary layer, also contributes to this limitation. Due to the conflicting effects of the indentations, the changes in the pressure-lift and pressure-drag coefficients, i.e., cl,p and cd,p, are small. Nevertheless, the indentations have improved cl,p and cd,p beyond the uncertainty range, i.e., by ~1.30% and ~0.30%, respectively, at 3° AoA. The wake measurements show that turbulence intensity and Reynolds stresses have considerably increased in the indented case, thus implying that the indentations increase the viscous drag on the model. In summary, the convergent indentations are able to reduce the size of the laminar separation bubble, but conversely, they are not highly effective in reducing cd,p at the tested Reynolds number. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=aerofoil%20flow%20control" title="aerofoil flow control">aerofoil flow control</a>, <a href="https://publications.waset.org/abstracts/search?q=laminar%20separation%20bubbles" title=" laminar separation bubbles"> laminar separation bubbles</a>, <a href="https://publications.waset.org/abstracts/search?q=low%20Reynolds-number%20flows" title=" low Reynolds-number flows"> low Reynolds-number flows</a>, <a href="https://publications.waset.org/abstracts/search?q=surface%20indentations" title=" surface indentations"> surface indentations</a> </p> <a href="https://publications.waset.org/abstracts/61082/flow-control-effectiveness-of-convergent-surface-indentations-on-an-aerofoil-at-low-reynolds-numbers" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/61082.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">226</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">16977</span> Simulations of Laminar Liquid Flows through Superhydrophobic Micro-Pipes</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Mohamed%20E.%20Eleshaky">Mohamed E. Eleshaky</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper investigates the dynamic behavior of laminar water flows inside superhydrophobic micro-pipes patterned with square micro-posts features under different operating conditions. It also investigates the effects of air fraction and Reynolds number on the frictional performance of these pipes. Rather than modeling the air-water interfaces of superhydrophobic as a flat inflexible surface, a transient, incompressible, three-dimensional, volume-of-fluid (VOF) methodology has been employed to continuously track the air–water interface shape inside micro-pipes. Also, the entrance effects on the flow field have been taken into consideration. The results revealed the strong dependency of the frictional performance on the air fractions and Reynolds number. The frictional resistance reduction becomes increasingly more significant at large air fractions and low Reynolds numbers. Increasing Reynolds number has an adverse effect on the frictional resistance reduction. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=drag%20reduction" title="drag reduction">drag reduction</a>, <a href="https://publications.waset.org/abstracts/search?q=laminar%20flow%20in%20micropipes" title=" laminar flow in micropipes"> laminar flow in micropipes</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=superhyrophobic%20surfaces" title=" superhyrophobic surfaces"> superhyrophobic surfaces</a>, <a href="https://publications.waset.org/abstracts/search?q=microposts" title=" microposts"> microposts</a> </p> <a href="https://publications.waset.org/abstracts/48306/simulations-of-laminar-liquid-flows-through-superhydrophobic-micro-pipes" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/48306.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">327</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">16976</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">16975</span> Numerical Analysis of Flow in the Gap between a Simplified Tractor-Trailer Model and Cross Vortex Trap Device</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Terrance%20Charles">Terrance Charles</a>, <a href="https://publications.waset.org/abstracts/search?q=Zhiyin%20Yang"> Zhiyin Yang</a>, <a href="https://publications.waset.org/abstracts/search?q=Yiling%20Lu"> Yiling Lu</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Heavy trucks are aerodynamically inefficient due to their un-streamlined body shapes, leading to more than of 60% engine power being required to overcome the aerodynamics drag at 60 m/hr. There are many aerodynamics drag reduction devices developed and this paper presents a study on a drag reduction device called Cross Vortex Trap Device (CVTD) deployed in the gap between the tractor and the trailer of a simplified tractor-trailer model. Numerical simulations have been carried out at Reynolds number 0.51×10<sup>6</sup> based on inlet flow velocity and height of the trailer using the Reynolds-Averaged Navier-Stokes (RANS) approach. Three different configurations of CVTD have been studied, ranging from single to three slabs, equally spaced on the front face of the trailer. Flow field around three different configurations of trap device have been analysed and presented. The results show that a maximum of 12.25% drag reduction can be achieved when a triple vortex trap device is used. Detailed flow field analysis along with pressure contours are presented to elucidate the drag reduction mechanisms of CVTD and why the triple vortex trap configuration produces the maximum drag reduction among the three configurations tested. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=aerodynamic%20drag" title="aerodynamic drag">aerodynamic drag</a>, <a href="https://publications.waset.org/abstracts/search?q=cross%20vortex%20trap%20device" title=" cross vortex trap device"> cross vortex trap device</a>, <a href="https://publications.waset.org/abstracts/search?q=truck" title=" truck"> truck</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds-Averaged%20Navier-Stokes" title=" Reynolds-Averaged Navier-Stokes"> Reynolds-Averaged Navier-Stokes</a>, <a href="https://publications.waset.org/abstracts/search?q=RANS" title=" RANS"> RANS</a> </p> <a href="https://publications.waset.org/abstracts/113731/numerical-analysis-of-flow-in-the-gap-between-a-simplified-tractor-trailer-model-and-cross-vortex-trap-device" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/113731.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">134</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">16974</span> Mixed Convective Heat Transfer in Water-Based Al2O3 Nanofluid in Horizontal Rectangular Duct</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Nur%20Irmawati">Nur Irmawati</a>, <a href="https://publications.waset.org/abstracts/search?q=H.%20A.%20Mohammed"> H. A. Mohammed</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In the present study, mixed convection in a horizontal rectangular duct using Al2O3 is numerically investigated. The effects of different Rayleigh number, Reynolds number and radiation on flow and heat transfer characteristics were studied in detail. This study covers Rayleigh number in the range of 2×106≤Ra≤2×107 and Reynolds number in the range of 100≤Re≤1100. Results reveal that the Nusselt number increases as Reynolds and Rayleigh numbers increase. It was also found that the dimensionless temperature distribution increases as Rayleigh number increases. <p class="card-text"><strong>Keywords:</strong> <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=mixed%20convection" title=" mixed convection"> mixed convection</a>, <a href="https://publications.waset.org/abstracts/search?q=horizontal%20rectangular%20duct" title=" horizontal rectangular duct"> horizontal rectangular duct</a>, <a href="https://publications.waset.org/abstracts/search?q=nanofluids" title=" nanofluids"> nanofluids</a> </p> <a href="https://publications.waset.org/abstracts/17914/mixed-convective-heat-transfer-in-water-based-al2o3-nanofluid-in-horizontal-rectangular-duct" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/17914.pdf" target="_blank" class="btn btn-primary 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