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conditions</title> <meta name="description" content="Search results for: boundary conditions"> <meta name="keywords" content="boundary conditions"> <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 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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="boundary conditions"> <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> 10648</div> </div> </div> </div> <h1 class="mt-3 mb-3 text-center" style="font-size:1.6rem;">Search results for: boundary conditions</h1> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">10438</span> Analysis of Potential Flow around Two-Dimensional Body by Surface Panel Method and Vortex Lattice Method</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=M.%20Abir%20Hossain">M. Abir Hossain</a>, <a href="https://publications.waset.org/abstracts/search?q=M.%20Shahjada%20Tarafder"> M. Shahjada Tarafder</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper deals with the analysis of potential flow past two-dimensional body by discretizing the body into panels where the Laplace equation was applied to each panel. The Laplace equation was solved at each panel by applying the boundary conditions. The boundary condition was applied at each panel to mathematically formulate the problem and then convert the problem into a computer-solvable problem. Kutta condition was applied at both the leading and trailing edges to see whether the condition is satisfied or not. Another approach that is applied for the analysis is Vortex Lattice Method (VLM). A vortex ring is considered at each control point. Using the Biot-Savart Law the strength at each control point is calculated and hence the pressure differentials are measured. For the comparison of the analytic result with the experimental result, different NACA section hydrofoil is used. The analytic result of NACA 0012 and NACA 0015 are compared with the experimental result of Abbott and Doenhoff and found significant conformity with the achieved result. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=Kutta%20condition" title="Kutta condition">Kutta condition</a>, <a href="https://publications.waset.org/abstracts/search?q=Law%20of%20Biot-Savart" title=" Law of Biot-Savart"> Law of Biot-Savart</a>, <a href="https://publications.waset.org/abstracts/search?q=pressure%20differentials" title=" pressure differentials"> pressure differentials</a>, <a href="https://publications.waset.org/abstracts/search?q=potential%20flow" title=" potential flow"> potential flow</a>, <a href="https://publications.waset.org/abstracts/search?q=vortex%20lattice%20method" title=" vortex lattice method"> vortex lattice method</a> </p> <a href="https://publications.waset.org/abstracts/81177/analysis-of-potential-flow-around-two-dimensional-body-by-surface-panel-method-and-vortex-lattice-method" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/81177.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">10437</span> Simulation of a Pressure Driven Based Subsonic Steady Gaseous Flow inside a Micro Channel Using Direct Simulation Monte-Carlo Method</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Asghar%20Ebrahimi">Asghar Ebrahimi</a>, <a href="https://publications.waset.org/abstracts/search?q=Elyas%20Lakzian"> Elyas Lakzian</a> </p> <p class="card-text"><strong>Abstract:</strong></p> For the analysis of flow inside micro geometries, classical CFD methods can not accurately predict the behavior of flow. Alternatively, the gas flow through micro geometries can be investigated precisely using the direct simulation Monte Carlo (DSMC) method. In the present paper, a pressure boundary condition is utilized to simulate a gaseous flow inside a micro channel using the DSMC method. Accuracy of simulation is guaranteed by choosing proper cell dimension and number of particle per cell analysis. Also, results of simulation are compared with the results of reliable references. Good agreement with results certifies the correctness of new boundary condition implemented on the micro channel. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=pressure%20boundary%20condition" title="pressure boundary condition">pressure boundary condition</a>, <a href="https://publications.waset.org/abstracts/search?q=DSMC" title=" DSMC"> DSMC</a>, <a href="https://publications.waset.org/abstracts/search?q=micro%20channel" title=" micro channel"> micro channel</a>, <a href="https://publications.waset.org/abstracts/search?q=cell%20dimension" title=" cell dimension"> cell dimension</a>, <a href="https://publications.waset.org/abstracts/search?q=particle%20per%20cell" title=" particle per cell"> particle per cell</a> </p> <a href="https://publications.waset.org/abstracts/20808/simulation-of-a-pressure-driven-based-subsonic-steady-gaseous-flow-inside-a-micro-channel-using-direct-simulation-monte-carlo-method" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/20808.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">478</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">10436</span> Three Dimensional Analysis of Cubesat Thermal Vacuum Test </h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Maged%20Assem%20Soliman%20Mossallam">Maged Assem Soliman Mossallam</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Thermal vacuum testing target is to qualify the space system and ensure its operability under harsh space environment. The functionality of the cubesat was checked at extreme orbit conditions. Test was performed for operational and nonoperational modes. Analysis is done to simulate the cubesat thermal cycling inside thermal vacuum chamber. Comsol Multiphysics finite element is used to solve three dimensional problem for the cubesat inside TVAC. Three dimensional CAD model is done using Autodesk Inventor program. The boundary conditions were applied from the actual shroud temperature. The input heat load variation with time is considered to solve the transient three dimensional problem. Results show that the simulated temperature profiles are within an acceptable range from the real testing data. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=cubesat" title="cubesat">cubesat</a>, <a href="https://publications.waset.org/abstracts/search?q=thermal%20vacuum%20test" title=" thermal vacuum test"> thermal vacuum test</a>, <a href="https://publications.waset.org/abstracts/search?q=testing%20simulation" title=" testing simulation"> testing simulation</a>, <a href="https://publications.waset.org/abstracts/search?q=finite%20element%20analysis" title=" finite element analysis "> finite element analysis </a> </p> <a href="https://publications.waset.org/abstracts/128852/three-dimensional-analysis-of-cubesat-thermal-vacuum-test" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/128852.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">10435</span> An Improved Mesh Deformation Method Based on Radial Basis Function</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Xuan%20Zhou">Xuan Zhou</a>, <a href="https://publications.waset.org/abstracts/search?q=Litian%20Zhang"> Litian Zhang</a>, <a href="https://publications.waset.org/abstracts/search?q=Shuixiang%20Li"> Shuixiang Li</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Mesh deformation using radial basis function interpolation method has been demonstrated to produce quality meshes with relatively little computational cost using a concise algorithm. However, it still suffers from the limited deformation ability, especially in large deformation. In this paper, a pre-displacement improvement is proposed to improve the problem that illegal meshes always appear near the moving inner boundaries owing to the large relative displacement of the nodes near inner boundaries. In this improvement, nodes near the inner boundaries are first associated to the near boundary nodes, and a pre-displacement based on the displacements of associated boundary nodes is added to the nodes near boundaries in order to make the displacement closer to the boundary deformation and improve the deformation capability. Several 2D and 3D numerical simulation cases have shown that the pre-displacement improvement for radial basis function (RBF) method significantly improves the mesh quality near inner boundaries and deformation capability, with little computational burden increasement. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=mesh%20deformation" title="mesh deformation">mesh deformation</a>, <a href="https://publications.waset.org/abstracts/search?q=mesh%20quality" title=" mesh quality"> mesh quality</a>, <a href="https://publications.waset.org/abstracts/search?q=background%20mesh" title=" background mesh"> background mesh</a>, <a href="https://publications.waset.org/abstracts/search?q=radial%20basis%20function" title=" radial basis function"> radial basis function</a> </p> <a href="https://publications.waset.org/abstracts/65928/an-improved-mesh-deformation-method-based-on-radial-basis-function" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/65928.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">366</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">10434</span> Study of a Lean Premixed Combustor: A Thermo Acoustic Analysis</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Minoo%20Ghasemzadeh">Minoo Ghasemzadeh</a>, <a href="https://publications.waset.org/abstracts/search?q=Rouzbeh%20Riazi"> Rouzbeh Riazi</a>, <a href="https://publications.waset.org/abstracts/search?q=Shidvash%20Vakilipour"> Shidvash Vakilipour</a>, <a href="https://publications.waset.org/abstracts/search?q=Alireza%20Ramezani"> Alireza Ramezani</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this study, thermo acoustic oscillations of a lean premixed combustor has been investigated, and a mono-dimensional code was developed in this regard. The linearized equations of motion are solved for perturbations with time dependence〖 e〗^iwt. Two flame models were considered in this paper and the effect of mean flow and boundary conditions were also investigated. After manipulation of flame heat release equation together with the equations of flow perturbation within the main components of the combustor model (i.e., plenum/ premixed duct/ and combustion chamber) and by considering proper boundary conditions between the components of model, a system of eight homogeneous equations can be obtained. This simplification, for the main components of the combustor model, is convenient since low frequency acoustic waves are not affected by bends. Moreover, some elements in the combustor are smaller than the wavelength of propagated acoustic perturbations. A convection time is also assumed to characterize the required time for the acoustic velocity fluctuations to travel from the point of injection to the location of flame front in the combustion chamber. The influence of an extended flame model on the acoustic frequencies of combustor was also investigated, assuming the effect of flame speed as a function of equivalence ratio perturbation, on the rate of flame heat release. The abovementioned system of equations has a related eigenvalue equation which has complex roots. The sign of imaginary part of these roots determines whether the disturbances grow or decay and the real part of these roots would give the frequency of the modes. The results show a reasonable agreement between the predicted values of dominant frequencies in the present model and those calculated in previous related studies. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=combustion%20instability" title="combustion instability">combustion instability</a>, <a href="https://publications.waset.org/abstracts/search?q=dominant%20frequencies" title=" dominant frequencies"> dominant frequencies</a>, <a href="https://publications.waset.org/abstracts/search?q=flame%20speed" title=" flame speed"> flame speed</a>, <a href="https://publications.waset.org/abstracts/search?q=premixed%20combustor" title=" premixed combustor"> premixed combustor</a> </p> <a href="https://publications.waset.org/abstracts/24231/study-of-a-lean-premixed-combustor-a-thermo-acoustic-analysis" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/24231.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">379</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">10433</span> Nonlinear Waves in Two-Layer Systems with Heat Release/Consumption at the Interface</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ilya%20Simanovskii">Ilya Simanovskii</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Nonlinear convective flows developed under the joint action of buoyant and thermo-capillary effects in a two-layer system with periodic boundary conditions on the lateral walls have been investigated. The influence of an interfacial heat release on oscillatory regimes has been studied. The computational regions with different lengths have been considered. It is shown that the development of oscillatory instability can lead to the appearance of different no steady flows. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=interface" title="interface">interface</a>, <a href="https://publications.waset.org/abstracts/search?q=instabilities" title=" instabilities"> instabilities</a>, <a href="https://publications.waset.org/abstracts/search?q=two-layer%20systems" title=" two-layer systems"> two-layer systems</a>, <a href="https://publications.waset.org/abstracts/search?q=bioinformatics" title=" bioinformatics"> bioinformatics</a>, <a href="https://publications.waset.org/abstracts/search?q=biomedicine" title=" biomedicine"> biomedicine</a> </p> <a href="https://publications.waset.org/abstracts/16427/nonlinear-waves-in-two-layer-systems-with-heat-releaseconsumption-at-the-interface" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/16427.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">401</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">10432</span> Effect of Loose Bonding and Corrugated Boundary Surface on Propagation of Rayleigh-Type Wave</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Kshitish%20Ch.%20Mistri">Kshitish Ch. Mistri</a>, <a href="https://publications.waset.org/abstracts/search?q=Abhishek%20Kumar%20Singh"> Abhishek Kumar Singh</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The effect of undulatory boundary surface of a medium as well as the degree of bonding between two consecutive mediums, on the propagation of surface waves is an unavoidable matter of fact. Therefore, this paper investigates the propagation of Rayleigh-type wave in a corrugated fibre-reinforced layer overlying an initially stressed orthotropic half-space under gravity. Also, the two mediums are assumed to be loosely (or imperfectly) bonded. Numerical computation of the obtained frequency equation has been carried out which aids to analyze the influence of corrugation, loose bonding, initial stress and gravity on the phase velocity of Rayleigh-type wave. Moreover, the presence and absence of corrugation, loose bonding and initial stress are also discussed in a comparative manner. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=corrugated%20boundary%20surface" title="corrugated boundary surface">corrugated boundary surface</a>, <a href="https://publications.waset.org/abstracts/search?q=fibre-reinforced%20layer" title=" fibre-reinforced layer"> fibre-reinforced layer</a>, <a href="https://publications.waset.org/abstracts/search?q=initial%20stress" title=" initial stress"> initial stress</a>, <a href="https://publications.waset.org/abstracts/search?q=loose%20bonding" title=" loose bonding"> loose bonding</a>, <a href="https://publications.waset.org/abstracts/search?q=orthotropic%20half-space" title=" orthotropic half-space"> orthotropic half-space</a>, <a href="https://publications.waset.org/abstracts/search?q=Rayleigh-type%20wave" title=" Rayleigh-type wave"> Rayleigh-type wave</a> </p> <a href="https://publications.waset.org/abstracts/60386/effect-of-loose-bonding-and-corrugated-boundary-surface-on-propagation-of-rayleigh-type-wave" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/60386.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">276</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">10431</span> Wind Turbine Wake Prediction and Validation under a Stably-Stratified Atmospheric Boundary Layer</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Yilei%20Song">Yilei Song</a>, <a href="https://publications.waset.org/abstracts/search?q=Linlin%20Tian"> Linlin Tian</a>, <a href="https://publications.waset.org/abstracts/search?q=Ning%20Zhao"> Ning Zhao</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Turbulence energetics and structures in the wake of large-scale wind turbines under the stably-stratified atmospheric boundary layer (SABL) can be complicated due to the presence of low-level jets (LLJs), a region of higher wind speeds than the geostrophic wind speed. With a modified one-k-equation, eddy viscosity model specified for atmospheric flows as the sub-grid scale (SGS) model, a realistic atmospheric state of the stable ABL is well reproduced by large-eddy simulation (LES) techniques. Corresponding to the precursor stably stratification, the detailed wake properties of a standard 5-MW wind turbine represented as an actuator line model are provided. An engineering model is proposed for wake prediction based on the simulation statistics and gets validated. Results confirm that the proposed wake model can provide good predictions for wind turbines under the SABL. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=large-eddy%20simulation" title="large-eddy simulation">large-eddy simulation</a>, <a href="https://publications.waset.org/abstracts/search?q=stably-stratified%20atmospheric%20boundary%20layer" title=" stably-stratified atmospheric boundary layer"> stably-stratified atmospheric boundary layer</a>, <a href="https://publications.waset.org/abstracts/search?q=wake%20model" title=" wake model"> wake model</a>, <a href="https://publications.waset.org/abstracts/search?q=wind%20turbine%20wake" title=" wind turbine wake"> wind turbine wake</a> </p> <a href="https://publications.waset.org/abstracts/111209/wind-turbine-wake-prediction-and-validation-under-a-stably-stratified-atmospheric-boundary-layer" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/111209.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">174</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">10430</span> Numerical Solutions of Boundary Layer Flow over an Exponentially Stretching/Shrinking Sheet with Generalized Slip Velocity</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Roslinda%20Nazar">Roslinda Nazar</a>, <a href="https://publications.waset.org/abstracts/search?q=Ezad%20Hafidz%20Hafidzuddin"> Ezad Hafidz Hafidzuddin</a>, <a href="https://publications.waset.org/abstracts/search?q=Norihan%20M.%20Arifin"> Norihan M. Arifin</a>, <a href="https://publications.waset.org/abstracts/search?q=Ioan%20Pop"> Ioan Pop</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this paper, the problem of steady laminar boundary layer flow and heat transfer over a permeable exponentially stretching/shrinking sheet with generalized slip velocity is considered. The similarity transformations are used to transform the governing nonlinear partial differential equations to a system of nonlinear ordinary differential equations. The transformed equations are then solved numerically using the bvp4c function in MATLAB. Dual solutions are found for a certain range of the suction and stretching/shrinking parameters. The effects of the suction parameter, stretching/shrinking parameter, velocity slip parameter, critical shear rate, and Prandtl number on the skin friction and heat transfer coefficients as well as the velocity and temperature profiles are presented and discussed. <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=exponentially%20stretching%2Fshrinking%20sheet" title=" exponentially stretching/shrinking sheet"> exponentially stretching/shrinking sheet</a>, <a href="https://publications.waset.org/abstracts/search?q=generalized%20slip" title=" generalized slip"> generalized slip</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=numerical%20solutions" title=" numerical solutions"> numerical solutions</a> </p> <a href="https://publications.waset.org/abstracts/28361/numerical-solutions-of-boundary-layer-flow-over-an-exponentially-stretchingshrinking-sheet-with-generalized-slip-velocity" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/28361.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">432</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">10429</span> Studying Relationship between Local Geometry of Decision Boundary with Network Complexity for Robustness Analysis with Adversarial Perturbations</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Tushar%20K.%20Routh">Tushar K. Routh</a> </p> <p class="card-text"><strong>Abstract:</strong></p> If inputs are engineered in certain manners, they can influence deep neural networks’ (DNN) performances by facilitating misclassifications, a phenomenon well-known as adversarial attacks that question networks’ vulnerability. Recent studies have unfolded the relationship between vulnerability of such networks with their complexity. In this paper, the distinctive influence of additional convolutional layers at the decision boundaries of several DNN architectures was investigated. Here, to engineer inputs from widely known image datasets like MNIST, Fashion MNIST, and Cifar 10, we have exercised One Step Spectral Attack (OSSA) and Fast Gradient Method (FGM) techniques. The aftermaths of adding layers to the robustness of the architectures have been analyzed. For reasoning, separation width from linear class partitions and local geometry (curvature) near the decision boundary have been examined. The result reveals that model complexity has significant roles in adjusting relative distances from margins, as well as the local features of decision boundaries, which impact robustness. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=DNN%20robustness" title="DNN robustness">DNN robustness</a>, <a href="https://publications.waset.org/abstracts/search?q=decision%20boundary" title=" decision boundary"> decision boundary</a>, <a href="https://publications.waset.org/abstracts/search?q=local%20curvature" title=" local curvature"> local curvature</a>, <a href="https://publications.waset.org/abstracts/search?q=network%20complexity" title=" network complexity"> network complexity</a> </p> <a href="https://publications.waset.org/abstracts/145321/studying-relationship-between-local-geometry-of-decision-boundary-with-network-complexity-for-robustness-analysis-with-adversarial-perturbations" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/145321.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">75</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">10428</span> Coexistence of Two Different Types of Intermittency near the Boundary of Phase Synchronization in the Presence of Noise</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Olga%20I.%20Moskalenko">Olga I. Moskalenko</a>, <a href="https://publications.waset.org/abstracts/search?q=Maksim%20O.%20Zhuravlev"> Maksim O. Zhuravlev</a>, <a href="https://publications.waset.org/abstracts/search?q=Alexey%20A.%20Koronovskii"> Alexey A. Koronovskii</a>, <a href="https://publications.waset.org/abstracts/search?q=Alexander%20E.%20Hramov"> Alexander E. Hramov</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Intermittent behavior near the boundary of phase synchronization in the presence of noise is studied. In certain range of the coupling parameter and noise intensity the intermittency of eyelet and ring intermittencies is shown to take place. Main results are illustrated using the example of two unidirectionally coupled Rössler systems. Similar behavior is shown to take place in two hydrodynamical models of Pierce diode coupled unidirectionally. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=chaotic%20oscillators" title="chaotic oscillators">chaotic oscillators</a>, <a href="https://publications.waset.org/abstracts/search?q=phase%20synchronization" title=" phase synchronization"> phase synchronization</a>, <a href="https://publications.waset.org/abstracts/search?q=noise" title=" noise"> noise</a>, <a href="https://publications.waset.org/abstracts/search?q=intermittency%20of%20intermittencies" title=" intermittency of intermittencies"> intermittency of intermittencies</a> </p> <a href="https://publications.waset.org/abstracts/27049/coexistence-of-two-different-types-of-intermittency-near-the-boundary-of-phase-synchronization-in-the-presence-of-noise" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/27049.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">642</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">10427</span> Evaluation of the Integration of a Direct Reduction Process into an Existing Steel Mill</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Nils%20Mueller">Nils Mueller</a>, <a href="https://publications.waset.org/abstracts/search?q=Gregor%20Herz"> Gregor Herz</a>, <a href="https://publications.waset.org/abstracts/search?q=Erik%20Reichelt"> Erik Reichelt</a>, <a href="https://publications.waset.org/abstracts/search?q=Matthias%20Jahn"> Matthias Jahn</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In the context of climate change, the reduction of greenhouse gas emissions in all economic sectors is considered to be an important factor in order to meet the demands of a sustainable energy system. The steel industry as one of the large industrial CO₂ emitters is currently highly dependent on fossil resources. In order to reduce coke consumption and thereby CO₂ emissions while still being able to further utilize existing blast furnaces, the possibility of including a direct reduction process (DRP) into a fully integrated steel mill was investigated. Therefore, a blast furnace model, derived from literature data and implemented in Aspen Plus, was used to analyze the impact of DRI in the blast furnace process. Furthermore, a state-of-the-art DRP was modeled to investigate the possibility of substituting the reducing agent natural gas with hydrogen. A sensitivity analysis was carried out in order to find the boundary percentage of hydrogen as a reducing agent without penalty to the DRI quality. Lastly, the two modeled process steps were combined to form a route of producing pig iron. By varying boundary conditions of the DRP while recording the CO₂ emissions of the two process steps, the overall potential for the reduction of CO₂ emissions was estimated. Within the simulated range, a maximum reduction of CO₂ emissions of 23.5% relative to typical emissions of a blast furnace could be determined. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=blast%20furnace" title="blast furnace">blast furnace</a>, <a href="https://publications.waset.org/abstracts/search?q=CO%E2%82%82%20mitigation" title=" CO₂ mitigation"> CO₂ mitigation</a>, <a href="https://publications.waset.org/abstracts/search?q=DRI" title=" DRI"> DRI</a>, <a href="https://publications.waset.org/abstracts/search?q=hydrogen" title=" hydrogen"> hydrogen</a> </p> <a href="https://publications.waset.org/abstracts/85789/evaluation-of-the-integration-of-a-direct-reduction-process-into-an-existing-steel-mill" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/85789.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">284</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">10426</span> Measure-Valued Solutions to a Class of Nonlinear Parabolic Equations with Degenerate Coercivity and Singular Initial Data</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Flavia%20Smarrazzo">Flavia Smarrazzo</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Initial-boundary value problems for nonlinear parabolic equations having a Radon measure as initial data have been widely investigated, looking for solutions which for positive times take values in some function space. On the other hand, if the diffusivity degenerates too fast at infinity, it is well known that function-valued solutions may not exist, singularities may persist, and it looks very natural to consider solutions which, roughly speaking, for positive times describe an orbit in the space of the finite Radon measures. In this general framework, our purpose is to introduce a concept of measure-valued solution which is consistent with respect to regularizing and smoothing approximations, in order to develop an existence theory which does not depend neither on the level of degeneracy of diffusivity at infinity nor on the choice of the initial measures. In more detail, we prove existence of suitably defined measure-valued solutions to the homogeneous Dirichlet initial-boundary value problem for a class of nonlinear parabolic equations without strong coerciveness. Moreover, we also discuss some qualitative properties of the constructed solutions concerning the evolution of their singular part, including conditions (depending both on the initial data and on the strength of degeneracy) under which the constructed solutions are in fact unction-valued or not. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=degenerate%20parabolic%20equations" title="degenerate parabolic equations">degenerate parabolic equations</a>, <a href="https://publications.waset.org/abstracts/search?q=measure-valued%20solutions" title=" measure-valued solutions"> measure-valued solutions</a>, <a href="https://publications.waset.org/abstracts/search?q=Radon%20measures" title=" Radon measures"> Radon measures</a>, <a href="https://publications.waset.org/abstracts/search?q=young%20measures" title=" young measures"> young measures</a> </p> <a href="https://publications.waset.org/abstracts/67367/measure-valued-solutions-to-a-class-of-nonlinear-parabolic-equations-with-degenerate-coercivity-and-singular-initial-data" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/67367.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">281</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">10425</span> Indirect Intergranular Slip Transfer Modeling Through Continuum Dislocation Dynamics</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=A.%20Kalaei">A. Kalaei</a>, <a href="https://publications.waset.org/abstracts/search?q=A.%20H.%20W.%20Ngan"> A. H. W. Ngan</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this study, a mesoscopic continuum dislocation dynamics (CDD) approach is applied to simulate the intergranular slip transfer. The CDD scheme applies an efficient kinematics equation to model the evolution of the “all-dislocation density,” which is the line-length of dislocations of each character per unit volume. As the consideration of every dislocation line can be a limiter for the simulation of slip transfer in large scales with a large quantity of participating dislocations, a coarse-grained, extensive description of dislocations in terms of their density is utilized to resolve the effect of collective motion of dislocation lines. For dynamics closure, namely, to obtain the dislocation velocity from a velocity law involving the effective glide stress, mutual elastic interaction of dislocations is calculated using Mura’s equation after singularity removal at the core of dislocation lines. The developed scheme for slip transfer can therefore resolve the effects of the elastic interaction and pile-up of dislocations, which are important physics omitted in coarser models like crystal plasticity finite element methods (CPFEMs). Also, the length and timescales of the simulationareconsiderably larger than those in molecular dynamics (MD) and discrete dislocation dynamics (DDD) models. The present work successfully simulates that, as dislocation density piles up in front of a grain boundary, the elastic stress on the other side increases, leading to dislocation nucleation and stress relaxation when the local glide stress exceeds the operation stress of dislocation sources seeded on the other side of the grain boundary. More importantly, the simulation verifiesa phenomenological misorientation factor often used by experimentalists, namely, the ease of slip transfer increases with the product of the cosines of misorientation angles of slip-plane normals and slip directions on either side of the grain boundary. Furthermore, to investigate the effects of the critical stress-intensity factor of the grain boundary, dislocation density sources are seeded at different distances from the grain boundary, and the critical applied stress to make slip transfer happen is studied. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=grain%20boundary" title="grain boundary">grain boundary</a>, <a href="https://publications.waset.org/abstracts/search?q=dislocation%20dynamics" title=" dislocation dynamics"> dislocation dynamics</a>, <a href="https://publications.waset.org/abstracts/search?q=slip%20transfer" title=" slip transfer"> slip transfer</a>, <a href="https://publications.waset.org/abstracts/search?q=elastic%20stress" title=" elastic stress"> elastic stress</a> </p> <a href="https://publications.waset.org/abstracts/155730/indirect-intergranular-slip-transfer-modeling-through-continuum-dislocation-dynamics" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/155730.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">123</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">10424</span> Series Solutions to Boundary Value Differential Equations</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Armin%20Ardekani">Armin Ardekani</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohammad%20Akbari"> Mohammad Akbari</a> </p> <p class="card-text"><strong>Abstract:</strong></p> We present a method of generating series solutions to large classes of nonlinear differential equations. The method is well suited to be adapted in mathematical software and unlike the available commercial solvers, we are capable of generating solutions to boundary value ODEs and PDEs. Many of the generated solutions converge to closed form solutions. Our method can also be applied to systems of ODEs or PDEs, providing all the solutions efficiently. As examples, we present results to many difficult differential equations in engineering fields. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=computational%20mathematics" title="computational mathematics">computational mathematics</a>, <a href="https://publications.waset.org/abstracts/search?q=differential%20equations" title=" differential equations"> differential equations</a>, <a href="https://publications.waset.org/abstracts/search?q=engineering" title=" engineering"> engineering</a>, <a href="https://publications.waset.org/abstracts/search?q=series" title=" series"> series</a> </p> <a href="https://publications.waset.org/abstracts/54764/series-solutions-to-boundary-value-differential-equations" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/54764.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">336</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">10423</span> Finite Volume Method in Loop Network in Hydraulic Transient</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Hossain%20Samani">Hossain Samani</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohammad%20Ehteram"> Mohammad Ehteram </a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this paper, we consider finite volume method (FVM) in water hammer. We will simulate these techniques on a looped network with complex boundary conditions. After comparing methods, we see the FVM method as the best method. We compare the results of FVM with experimental data. Finite volume using staggered grid is applied for solving water hammer equations. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=hydraulic%20transient" title="hydraulic transient">hydraulic transient</a>, <a href="https://publications.waset.org/abstracts/search?q=water%20hammer" title=" water hammer"> water hammer</a>, <a href="https://publications.waset.org/abstracts/search?q=interpolation" title=" interpolation"> interpolation</a>, <a href="https://publications.waset.org/abstracts/search?q=non-liner%20interpolation" title=" non-liner interpolation "> non-liner interpolation </a> </p> <a href="https://publications.waset.org/abstracts/12178/finite-volume-method-in-loop-network-in-hydraulic-transient" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/12178.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">349</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">10422</span> Combining the Fictitious Stress Method and Displacement Discontinuity Method in Solving Crack Problems in Anisotropic Material</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Bahatti%CC%87n%20Ki%CC%87men%C3%A7e">Bahatti̇n Ki̇mençe</a>, <a href="https://publications.waset.org/abstracts/search?q=U%C4%9Fur%20Ki%CC%87men%C3%A7e"> Uğur Ki̇mençe</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this study, the purpose of obtaining the influence functions of the displacement discontinuity in an anisotropic elastic medium is to produce the boundary element equations. A Displacement Discontinuous Method formulation (DDM) is presented with the aim of modeling two-dimensional elastic fracture problems. This formulation is found by analytical integration of the fundamental solution along a straight-line crack. With this purpose, Kelvin's fundamental solutions for anisotropic media on an infinite plane are used to form dipoles from singular loads, and the various combinations of the said dipoles are used to obtain the influence functions of displacement discontinuity. This study introduces a technique for coupling Fictitious Stress Method (FSM) and DDM; the reason for applying this technique to some examples is to demonstrate the effectiveness of the proposed coupling method. In this study, displacement discontinuity equations are obtained by using dipole solutions calculated with known singular force solutions in an anisotropic medium. The displacement discontinuities method obtained from the solutions of these equations and the fictitious stress methods is combined and compared with various examples. In this study, one or more crack problems with various geometries in rectangular plates in finite and infinite regions, under the effect of tensile stress with coupled FSM and DDM in the anisotropic environment, were examined, and the effectiveness of the coupled method was demonstrated. Since crack problems can be modeled more easily with DDM, it has been observed that the use of DDM has increased recently. In obtaining the displacement discontinuity equations, Papkovitch functions were used in Crouch, and harmonic functions were chosen to satisfy various boundary conditions. A comparison is made between two indirect boundary element formulations, DDM, and an extension of FSM, for solving problems involving cracks. Several numerical examples are presented, and the outcomes are contrasted to existing analytical or reference outs. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=displacement%20discontinuity%20method" title="displacement discontinuity method">displacement discontinuity method</a>, <a href="https://publications.waset.org/abstracts/search?q=fictitious%20stress%20method" title=" fictitious stress method"> fictitious stress method</a>, <a href="https://publications.waset.org/abstracts/search?q=crack%20problems" title=" crack problems"> crack problems</a>, <a href="https://publications.waset.org/abstracts/search?q=anisotropic%20material" title=" anisotropic material"> anisotropic material</a> </p> <a href="https://publications.waset.org/abstracts/162296/combining-the-fictitious-stress-method-and-displacement-discontinuity-method-in-solving-crack-problems-in-anisotropic-material" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/162296.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">75</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">10421</span> Static and Dynamic Analysis of Timoshenko Microcantilever Using the Finite Element Method</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Mohammad%20Tahmasebipour">Mohammad Tahmasebipour</a>, <a href="https://publications.waset.org/abstracts/search?q=Hosein%20Salarpour"> Hosein Salarpour</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Micro cantilevers are one of the components used in the manufacture of micro-electromechanical systems. Epoxy microcantilevers have a variety of applications in the manufacture of micro-sensors and micro-actuators. In this paper, the Timoshenko Micro cantilever was statically and dynamically analyzed using the finite element method. First, all boundary conditions and initial conditions governing micro cantilevers were considered. The effect of size on the deflection, angle of rotation, natural frequencies, and mode shapes were then analyzed and evaluated under different frequencies. It was observed that an increased micro cantilever thickness reduces the deflection, rotation, and resonant frequency. A good agreement was observed between our results and those obtained by the couple stress theory, the classical theory, and the strain gradient elasticity theory. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=microcantilever" title="microcantilever">microcantilever</a>, <a href="https://publications.waset.org/abstracts/search?q=microsensor%3B%20epoxy" title=" microsensor; epoxy"> microsensor; epoxy</a>, <a href="https://publications.waset.org/abstracts/search?q=dynamic%20behavior" title=" dynamic behavior"> dynamic behavior</a>, <a href="https://publications.waset.org/abstracts/search?q=static%20behavior" title=" static behavior"> static behavior</a>, <a href="https://publications.waset.org/abstracts/search?q=finite%20element%20method" title=" finite element method"> finite element method</a> </p> <a href="https://publications.waset.org/abstracts/28159/static-and-dynamic-analysis-of-timoshenko-microcantilever-using-the-finite-element-method" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/28159.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">416</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">10420</span> The Phonology and Phonetics of Second Language Intonation in Case of “Downstep”</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Tayebeh%20Norouzi">Tayebeh Norouzi</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This study aims to investigate the acquisition process of intonation. It examines the intonation structure of Tokyo Japanese and its realization by Iranian learners of Japanese. Seven Iranian learners of Japanese, differing in fluency, and two Japanese speakers participated in the experiment. Two sentences were used to test the phonological and phonetic characteristics of lexical pitch-accent as well as the intonation patterns produced by the speakers. Both sentences consisted of similar words with the same number of syllables and lexical pitch-accents but different syntactic structure. Speakers were asked to read each sentence three times at normal speed, and the data were analyzed by Praat. The results show that lexical pitch-accent, Accentual Phrase (AP) and AP boundary tone realization vary depending on sentence type. For sentences of type <em>XdeYwo</em>, the lexical pitch-accent is realized properly. However, there is a rise in AP boundary tone regardless of speakers’ level of fluency. In contrast, in sentences of type <em>XnoYwo</em>, the lexical pitch-accent and AP boundary tone vary depending on the speakers’ fluency level. Advanced speakers are better at grouping words into phrases and produce more native-like intonation patterns, though they are not able to realize downstep properly. The non-native speakers tried to realize proper intonation patterns by making changes in lexical accent and boundary tone. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=intonation" title="intonation">intonation</a>, <a href="https://publications.waset.org/abstracts/search?q=Iranian%20learners" title=" Iranian learners"> Iranian learners</a>, <a href="https://publications.waset.org/abstracts/search?q=Japanese%20prosody" title=" Japanese prosody"> Japanese prosody</a>, <a href="https://publications.waset.org/abstracts/search?q=lexical%20accent" title=" lexical accent"> lexical accent</a>, <a href="https://publications.waset.org/abstracts/search?q=second%20language%20acquisition." title=" second language acquisition."> second language acquisition.</a> </p> <a href="https://publications.waset.org/abstracts/89060/the-phonology-and-phonetics-of-second-language-intonation-in-case-of-downstep" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/89060.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">169</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">10419</span> Computational Code for Solving the Navier-Stokes Equations on Unstructured Meshes Applied to the Leading Edge of the Brazilian Hypersonic Scramjet 14-X</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Jayme%20R.%20T.%20Silva">Jayme R. T. Silva</a>, <a href="https://publications.waset.org/abstracts/search?q=Paulo%20G.%20P.%20Toro"> Paulo G. P. Toro</a>, <a href="https://publications.waset.org/abstracts/search?q=Angelo%20Passaro"> Angelo Passaro</a>, <a href="https://publications.waset.org/abstracts/search?q=Giannino%20P.%20Camillo"> Giannino P. Camillo</a>, <a href="https://publications.waset.org/abstracts/search?q=Antonio%20C.%20Oliveira"> Antonio C. Oliveira</a> </p> <p class="card-text"><strong>Abstract:</strong></p> An in-house C++ code has been developed, at the Prof. Henry T. Nagamatsu Laboratory of Aerothermodynamics and Hypersonics from the Institute of Advanced Studies (Brazil), to estimate the aerothermodynamic properties around the Hypersonic Vehicle Integrated to the Scramjet. In the future, this code will be applied to the design of the Brazilian Scramjet Technological Demonstrator 14-X B. The first step towards accomplishing this objective, is to apply the in-house C++ code at the leading edge of a flat plate, simulating the leading edge of the 14-X Hypersonic Vehicle, making possible the wave phenomena of oblique shock and boundary layer to be analyzed. The development of modern hypersonic space vehicles requires knowledge regarding the characteristics of hypersonic flows in the vicinity of a leading edge of lifting surfaces. The strong interaction between a shock wave and a boundary layer, in a high supersonic Mach number 4 viscous flow, close to the leading edge of the plate, considering no slip condition, is numerically investigated. The small slip region is neglecting. The study consists of solving the fluid flow equations for unstructured meshes applying the SIMPLE algorithm for Finite Volume Method. Unstructured meshes are generated by the in-house software ‘Modeler’ that was developed at Virtual’s Engineering Laboratory from the Institute of Advanced Studies, initially developed for Finite Element problems and, in this work, adapted to the resolution of the Navier-Stokes equations based on the SIMPLE pressure-correction scheme for all-speed flows, Finite Volume Method based. The in-house C++ code is based on the two-dimensional Navier-Stokes equations considering non-steady flow, with nobody forces, no volumetric heating, and no mass diffusion. Air is considered as calorically perfect gas, with constant Prandtl number and Sutherland's law for the viscosity. Solutions of the flat plate problem for Mach number 4 include pressure, temperature, density and velocity profiles as well as 2-D contours. Also, the boundary layer thickness, boundary conditions, and mesh configurations are presented. The same problem has been solved by the academic license of the software Ansys Fluent and for another C++ in-house code, which solves the fluid flow equations in structured meshes, applying the MacCormack method for Finite Difference Method, and the results will be compared. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=boundary-layer" title="boundary-layer">boundary-layer</a>, <a href="https://publications.waset.org/abstracts/search?q=scramjet" title=" scramjet"> scramjet</a>, <a href="https://publications.waset.org/abstracts/search?q=simple%20algorithm" title=" simple algorithm"> simple algorithm</a>, <a href="https://publications.waset.org/abstracts/search?q=shock%20wave" title=" shock wave"> shock wave</a> </p> <a href="https://publications.waset.org/abstracts/59536/computational-code-for-solving-the-navier-stokes-equations-on-unstructured-meshes-applied-to-the-leading-edge-of-the-brazilian-hypersonic-scramjet-14-x" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/59536.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">491</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">10418</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">10417</span> Evaluation of Deformable Boundary Condition Using Finite Element Method and Impact Test for Steel Tubes</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Abed%20Ahmed">Abed Ahmed</a>, <a href="https://publications.waset.org/abstracts/search?q=Mehrdad%20Asadi"> Mehrdad Asadi</a>, <a href="https://publications.waset.org/abstracts/search?q=Jennifer%20Martay"> Jennifer Martay</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Stainless steel pipelines are crucial components to transportation and storage in the oil and gas industry. However, the rise of random attacks and vandalism on these pipes for their valuable transport has led to more security and protection for incoming surface impacts. These surface impacts can lead to large global deformations of the pipe and place the pipe under strain, causing the eventual failure of the pipeline. Therefore, understanding how these surface impact loads affect the pipes is vital to improving the pipes’ security and protection. In this study, experimental test and finite element analysis (FEA) have been carried out on EN3B stainless steel specimens to study the impact behaviour. Low velocity impact tests at 9 m/s with 16 kg dome impactor was used to simulate for high momentum impact for localised failure. FEA models of clamped and deformable boundaries were modelled to study the effect of the boundaries on the pipes impact behaviour on its impact resistance, using experimental and FEA approach. Comparison of experimental and FE simulation shows good correlation to the deformable boundaries in order to validate the robustness of the FE model to be implemented in pipe models with complex anisotropic structure. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=dynamic%20impact" title="dynamic impact">dynamic impact</a>, <a href="https://publications.waset.org/abstracts/search?q=deformable%20boundary%20conditions" title=" deformable boundary conditions"> deformable boundary conditions</a>, <a href="https://publications.waset.org/abstracts/search?q=finite%20element%20modelling" title=" finite element modelling"> finite element modelling</a>, <a href="https://publications.waset.org/abstracts/search?q=LS-DYNA" title=" LS-DYNA"> LS-DYNA</a>, <a href="https://publications.waset.org/abstracts/search?q=stainless%20steel%20pipe" title=" stainless steel pipe"> stainless steel pipe</a> </p> <a href="https://publications.waset.org/abstracts/116559/evaluation-of-deformable-boundary-condition-using-finite-element-method-and-impact-test-for-steel-tubes" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/116559.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">10416</span> The Data-Driven Localized Wave Solution of the Fokas-Lenells Equation Using Physics-Informed Neural Network</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Gautam%20Kumar%20Saharia">Gautam Kumar Saharia</a>, <a href="https://publications.waset.org/abstracts/search?q=Sagardeep%20Talukdar"> Sagardeep Talukdar</a>, <a href="https://publications.waset.org/abstracts/search?q=Riki%20Dutta"> Riki Dutta</a>, <a href="https://publications.waset.org/abstracts/search?q=Sudipta%20Nandy"> Sudipta Nandy</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The physics-informed neural network (PINN) method opens up an approach for numerically solving nonlinear partial differential equations leveraging fast calculating speed and high precession of modern computing systems. We construct the PINN based on a strong universal approximation theorem and apply the initial-boundary value data and residual collocation points to weekly impose initial and boundary conditions to the neural network and choose the optimization algorithms adaptive moment estimation (ADAM) and Limited-memory Broyden-Fletcher-Golfard-Shanno (L-BFGS) algorithm to optimize learnable parameter of the neural network. Next, we improve the PINN with a weighted loss function to obtain both the bright and dark soliton solutions of the Fokas-Lenells equation (FLE). We find the proposed scheme of adjustable weight coefficients into PINN has a better convergence rate and generalizability than the basic PINN algorithm. We believe that the PINN approach to solve the partial differential equation appearing in nonlinear optics would be useful in studying various optical phenomena. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=deep%20learning" title="deep learning">deep learning</a>, <a href="https://publications.waset.org/abstracts/search?q=optical%20soliton" title=" optical soliton"> optical soliton</a>, <a href="https://publications.waset.org/abstracts/search?q=physics%20informed%20neural%20network" title=" physics informed neural network"> physics informed neural network</a>, <a href="https://publications.waset.org/abstracts/search?q=partial%20differential%20equation" title=" partial differential equation"> partial differential equation</a> </p> <a href="https://publications.waset.org/abstracts/165242/the-data-driven-localized-wave-solution-of-the-fokas-lenells-equation-using-physics-informed-neural-network" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/165242.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">10415</span> Development of a New Method for T-Joint Specimens Testing under Shear Loading</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Radek%20Doubrava">Radek Doubrava</a>, <a href="https://publications.waset.org/abstracts/search?q=Roman%20Ruzek"> Roman Ruzek</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Nonstandard tests are necessary for analyses and verification of new developed structural and technological solutions with application of composite materials. One of the most critical primary structural parts of a typical aerospace structure is T-joint. This structural element is loaded mainly in shear, bending, peel and tension. The paper is focused on the shear loading simulations. The aim of the work is to obtain a representative uniform distribution of shear loads along T-joint during the mechanical testing is. A new design of T-joint test procedure, numerical simulation and optimization of representative boundary conditions are presented. The different conditions and inaccuracies both in simulations and experiments are discussed. The influence of different parameters on stress and strain distributions is demonstrated on T-joint made of CFRP (carbon fiber reinforced plastic). A special test rig designed by VZLU (Aerospace Research and Test Establishment) for T-shear test procedure is presented. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=T-joint" title="T-joint">T-joint</a>, <a href="https://publications.waset.org/abstracts/search?q=shear" title=" shear"> shear</a>, <a href="https://publications.waset.org/abstracts/search?q=composite" title=" composite"> composite</a>, <a href="https://publications.waset.org/abstracts/search?q=mechanical%20testing" title=" mechanical testing"> mechanical testing</a>, <a href="https://publications.waset.org/abstracts/search?q=finite%20element%20analysis" title=" finite element analysis"> finite element analysis</a>, <a href="https://publications.waset.org/abstracts/search?q=methodology" title=" methodology"> methodology</a> </p> <a href="https://publications.waset.org/abstracts/17685/development-of-a-new-method-for-t-joint-specimens-testing-under-shear-loading" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/17685.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">442</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">10414</span> Stress Analysis of a Pressurizer in a Pressurized Water Reactor Using Finite Element Method</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Tanvir%20Hasan">Tanvir Hasan</a>, <a href="https://publications.waset.org/abstracts/search?q=Minhaz%20Uddin"> Minhaz Uddin</a>, <a href="https://publications.waset.org/abstracts/search?q=Anwar%20Sadat%20Anik"> Anwar Sadat Anik</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A pressurizer is a safety-related reactor component that maintains the reactor operating pressure to guarantee safety. Its structure is usually made of high thermal and pressure resistive material. The mechanical structure of these components should be maintained in all working settings, including transient to severe accidents conditions. The goal of this study is to examine the structural integrity and stress of the pressurizer in order to ensure its design integrity towards transient situations. For this, the finite element method (FEM) was used to analyze the mechanical stress on pressurizer components in this research. ANSYS MECHANICAL tool was used to analyze a 3D model of the pressurizer. The material for the body and safety relief nozzle is selected as low alloy steel i.e., SA-508 Gr.3 Cl.2. The model was put into ANSYS WORKBENCH and run under the boundary conditions of (internal Pressure, -17.2 MPa, inside radius, -1348mm, the thickness of the shell, -127mm, and the ratio of the outside radius to an inside radius, - 1.059). The theoretical calculation was done using the formulas and then the results were compared with the simulated results. When stimulated at design conditions, the findings revealed that the pressurizer stress analysis completely fulfilled the ASME standards. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=pressurizer" title="pressurizer">pressurizer</a>, <a href="https://publications.waset.org/abstracts/search?q=stress%20analysis" title=" stress analysis"> stress analysis</a>, <a href="https://publications.waset.org/abstracts/search?q=finite%20element%20method" title=" finite element method"> finite element method</a>, <a href="https://publications.waset.org/abstracts/search?q=nuclear%20reactor" title=" nuclear reactor"> nuclear reactor</a> </p> <a href="https://publications.waset.org/abstracts/144496/stress-analysis-of-a-pressurizer-in-a-pressurized-water-reactor-using-finite-element-method" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/144496.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">158</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">10413</span> Surface Roughness Prediction Using Numerical Scheme and Adaptive Control</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Michael%20K.O.%20Ayomoh">Michael K.O. Ayomoh</a>, <a href="https://publications.waset.org/abstracts/search?q=Khaled%20A.%20Abou-El-Hossein."> Khaled A. Abou-El-Hossein.</a>, <a href="https://publications.waset.org/abstracts/search?q=Sameh%20F.M.%20Ghobashy"> Sameh F.M. Ghobashy</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper proposes a numerical modelling scheme for surface roughness prediction. The approach is premised on the use of 3D difference analysis method enhanced with the use of feedback control loop where a set of adaptive weights are generated. The surface roughness values utilized in this paper were adapted from [1]. Their experiments were carried out using S55C high carbon steel. A comparison was further carried out between the proposed technique and those utilized in [1]. The experimental design has three cutting parameters namely: depth of cut, feed rate and cutting speed with twenty-seven experimental sample-space. The simulation trials conducted using Matlab software is of two sub-classes namely: prediction of the surface roughness readings for the non-boundary cutting combinations (NBCC) with the aid of the known surface roughness readings of the boundary cutting combinations (BCC). The following simulation involved the use of the predicted outputs from the NBCC to recover the surface roughness readings for the boundary cutting combinations (BCC). The simulation trial for the NBCC attained a state of total stability in the 7th iteration i.e. a point where the actual and desired roughness readings are equal such that error is minimized to zero by using a set of dynamic weights generated in every following simulation trial. A comparative study among the three methods showed that the proposed difference analysis technique with adaptive weight from feedback control, produced a much accurate output as against the abductive and regression analysis techniques presented in this. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=Difference%20Analysis" title="Difference Analysis">Difference Analysis</a>, <a href="https://publications.waset.org/abstracts/search?q=Surface%20Roughness%3B%20Mesh-%20Analysis" title=" Surface Roughness; Mesh- Analysis"> Surface Roughness; Mesh- Analysis</a>, <a href="https://publications.waset.org/abstracts/search?q=Feedback%20control" title=" Feedback control"> Feedback control</a>, <a href="https://publications.waset.org/abstracts/search?q=Adaptive%20weight" title=" Adaptive weight"> Adaptive weight</a>, <a href="https://publications.waset.org/abstracts/search?q=Boundary%20Element" title=" Boundary Element"> Boundary Element</a> </p> <a href="https://publications.waset.org/abstracts/22817/surface-roughness-prediction-using-numerical-scheme-and-adaptive-control" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/22817.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">621</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">10412</span> Asymptotic Analysis of the Viscous Flow through a Pipe and the Derivation of the Darcy-Weisbach Law</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Eduard%20Marusic-Paloka">Eduard Marusic-Paloka</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The Darcy-Weisbach formula is used to compute the pressure drop of the fluid in the pipe, due to the friction against the wall. Because of its simplicity, the Darcy-Weisbach formula became widely accepted by engineers and is used for laminar as well as the turbulent flows through pipes, once the method to compute the mysterious friction coefficient was derived. Particularly in the second half of the 20th century. Formula is empiric, and our goal is to derive it from the basic conservation law, via rigorous asymptotic analysis. We consider the case of the laminar flow but with significant Reynolds number. In case of the perfectly smooth pipe, the situation is trivial, as the Navier-Stokes system can be solved explicitly via the Poiseuille formula leading to the friction coefficient in the form 64/Re. For the rough pipe, the situation is more complicated and some effects of the roughness appear in the friction coefficient. We start from the Navier-Stokes system in the pipe with periodically corrugated wall and derive an asymptotic expansion for the pressure and for the velocity. We use the homogenization techniques and the boundary layer analysis. The approximation derived by formal analysis is then justified by rigorous error estimate in the norm of the appropriate Sobolev space, using the energy formulation and classical a priori estimates for the Navier-Stokes system. Our method leads to the formula for the friction coefficient. The formula involves resolution of the appropriate boundary layer problems, namely the boundary value problems for the Stokes system in an infinite band, that needs to be done numerically. However, theoretical analysis characterising their nature can be done without solving them. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=Darcy-Weisbach%20law" title="Darcy-Weisbach law">Darcy-Weisbach law</a>, <a href="https://publications.waset.org/abstracts/search?q=pipe%20flow" title=" pipe flow"> pipe flow</a>, <a href="https://publications.waset.org/abstracts/search?q=rough%20boundary" title=" rough boundary"> rough boundary</a>, <a href="https://publications.waset.org/abstracts/search?q=Navier%20law" title=" Navier law"> Navier law</a> </p> <a href="https://publications.waset.org/abstracts/84028/asymptotic-analysis-of-the-viscous-flow-through-a-pipe-and-the-derivation-of-the-darcy-weisbach-law" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/84028.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">353</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">10411</span> Three Dimensional Large Eddy Simulation of Blood Flow and Deformation in an Elastic Constricted Artery</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Xi%20Gu">Xi Gu</a>, <a href="https://publications.waset.org/abstracts/search?q=Guan%20Heng%20Yeoh"> Guan Heng Yeoh</a>, <a href="https://publications.waset.org/abstracts/search?q=Victoria%20Timchenko"> Victoria Timchenko</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In the current work, a three-dimensional geometry of a 75% stenosed blood vessel is analysed. Large eddy simulation (LES) with the help of a dynamic subgrid scale Smagorinsky model is applied to model the turbulent pulsatile flow. The geometry, the transmural pressure and the properties of the blood and the elastic boundary were based on clinical measurement data. For the flexible wall model, a thin solid region is constructed around the 75% stenosed blood vessel. The deformation of this solid region was modelled as a deforming boundary to reduce the computational cost of the solid model. Fluid-structure interaction is realised via a two-way coupling between the blood flow modelled via LES and the deforming vessel. The information of the flow pressure and the wall motion was exchanged continually during the cycle by an arbitrary lagrangian-eulerian method. The boundary condition of current time step depended on previous solutions. The fluctuation of the velocity in the post-stenotic region was analysed in the study. The axial velocity at normalised position Z=0.5 shows a negative value near the vessel wall. The displacement of the elastic boundary was concerned in this study. In particular, the wall displacement at the systole and the diastole were compared. The negative displacement at the stenosis indicates a collapse at the maximum velocity and the deceleration phase. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=Large%20Eddy%20Simulation" title="Large Eddy Simulation">Large Eddy Simulation</a>, <a href="https://publications.waset.org/abstracts/search?q=Fluid%20Structural%20Interaction" title=" Fluid Structural Interaction"> Fluid Structural Interaction</a>, <a href="https://publications.waset.org/abstracts/search?q=constricted%20artery" title=" constricted artery"> constricted artery</a>, <a href="https://publications.waset.org/abstracts/search?q=Computational%20Fluid%20Dynamics" title=" Computational Fluid Dynamics"> Computational Fluid Dynamics</a> </p> <a href="https://publications.waset.org/abstracts/21203/three-dimensional-large-eddy-simulation-of-blood-flow-and-deformation-in-an-elastic-constricted-artery" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/21203.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">293</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">10410</span> Polynomial Chaos Expansion Combined with Exponential Spline for Singularly Perturbed Boundary Value Problems with Random Parameter</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=W.%20K.%20Zahra">W. K. Zahra</a>, <a href="https://publications.waset.org/abstracts/search?q=M.%20A.%20El-Beltagy"> M. A. El-Beltagy</a>, <a href="https://publications.waset.org/abstracts/search?q=R.%20R.%20Elkhadrawy"> R. R. Elkhadrawy</a> </p> <p class="card-text"><strong>Abstract:</strong></p> So many practical problems in science and technology developed over the past decays. For instance, the mathematical boundary layer theory or the approximation of solution for different problems described by differential equations. When such problems consider large or small parameters, they become increasingly complex and therefore require the use of asymptotic methods. In this work, we consider the singularly perturbed boundary value problems which contain very small parameters. Moreover, we will consider these perturbation parameters as random variables. We propose a numerical method to solve this kind of problems. The proposed method is based on an exponential spline, Shishkin mesh discretization, and polynomial chaos expansion. The polynomial chaos expansion is used to handle the randomness exist in the perturbation parameter. Furthermore, the Monte Carlo Simulations (MCS) are used to validate the solution and the accuracy of the proposed method. Numerical results are provided to show the applicability and efficiency of the proposed method, which maintains a very remarkable high accuracy and it is ε-uniform convergence of almost second order. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=singular%20perturbation%20problem" title="singular perturbation problem">singular perturbation problem</a>, <a href="https://publications.waset.org/abstracts/search?q=polynomial%20chaos%20expansion" title=" polynomial chaos expansion"> polynomial chaos expansion</a>, <a href="https://publications.waset.org/abstracts/search?q=Shishkin%20mesh" title=" Shishkin mesh"> Shishkin mesh</a>, <a href="https://publications.waset.org/abstracts/search?q=two%20small%20parameters" title=" two small parameters"> two small parameters</a>, <a href="https://publications.waset.org/abstracts/search?q=exponential%20spline" title=" exponential spline"> exponential spline</a> </p> <a href="https://publications.waset.org/abstracts/100441/polynomial-chaos-expansion-combined-with-exponential-spline-for-singularly-perturbed-boundary-value-problems-with-random-parameter" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/100441.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">160</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">10409</span> Analytical and Numerical Modeling of Strongly Rotating Rarefied Gas Flows</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=S.%20Pradhan">S. Pradhan</a>, <a href="https://publications.waset.org/abstracts/search?q=V.%20Kumaran"> V. Kumaran </a> </p> <p class="card-text"><strong>Abstract:</strong></p> Centrifugal gas separation processes effect separation by utilizing the difference in the mole fraction in a high speed rotating cylinder caused by the difference in molecular mass, and consequently the centrifugal force density. These have been widely used in isotope separation because chemical separation methods cannot be used to separate isotopes of the same chemical species. More recently, centrifugal separation has also been explored for the separation of gases such as carbon dioxide and methane. The efficiency of separation is critically dependent on the secondary flow generated due to temperature gradients at the cylinder wall or due to inserts, and it is important to formulate accurate models for this secondary flow. The widely used Onsager model for secondary flow is restricted to very long cylinders where the length is large compared to the diameter, the limit of high stratification parameter, where the gas is restricted to a thin layer near the wall of the cylinder, and it assumes that there is no mass difference in the two species while calculating the secondary flow. There are two objectives of the present analysis of the rarefied gas flow in a rotating cylinder. The first is to remove the restriction of high stratification parameter, and to generalize the solutions to low rotation speeds where the stratification parameter may be O (1), and to apply for dissimilar gases considering the difference in molecular mass of the two species. Secondly, we would like to compare the predictions with molecular simulations based on the direct simulation Monte Carlo (DSMC) method for rarefied gas flows, in order to quantify the errors resulting from the approximations at different aspect ratios, Reynolds number and stratification parameter. In this study, we have obtained analytical and numerical solutions for the secondary flows generated at the cylinder curved surface and at the end-caps due to linear wall temperature gradient and external gas inflow/outflow at the axis of the cylinder. The effect of sources of mass, momentum and energy within the flow domain are also analyzed. The results of the analytical solutions are compared with the results of DSMC simulations for three types of forcing, a wall temperature gradient, inflow/outflow of gas along the axis, and mass/momentum input due to inserts within the flow. The comparison reveals that the boundary conditions in the simulations and analysis have to be matched with care. The commonly used diffuse reflection boundary conditions at solid walls in DSMC simulations result in a non-zero slip velocity as well as a temperature slip (gas temperature at the wall is different from wall temperature). These have to be incorporated in the analysis in order to make quantitative predictions. In the case of mass/momentum/energy sources within the flow, it is necessary to ensure that the homogeneous boundary conditions are accurately satisfied in the simulations. When these precautions are taken, there is excellent agreement between analysis and simulations, to within 10 %, even when the stratification parameter is as low as 0.707, the Reynolds number is as low as 100 and the aspect ratio (length/diameter) of the cylinder is as low as 2, and the secondary flow velocity is as high as 0.2 times the maximum base flow velocity. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=rotating%20flows" title="rotating flows">rotating flows</a>, <a href="https://publications.waset.org/abstracts/search?q=generalized%20onsager%20and%20carrier-Maslen%20model" title=" generalized onsager and carrier-Maslen model"> generalized onsager and carrier-Maslen model</a>, <a href="https://publications.waset.org/abstracts/search?q=DSMC%20simulations" title=" DSMC simulations"> DSMC simulations</a>, <a href="https://publications.waset.org/abstracts/search?q=rarefied%20gas%20flow" title=" rarefied gas flow"> rarefied gas flow</a> </p> <a href="https://publications.waset.org/abstracts/16153/analytical-and-numerical-modeling-of-strongly-rotating-rarefied-gas-flows" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/16153.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> <ul class="pagination"> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=boundary%20conditions&page=7" rel="prev">&lsaquo;</a></li> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=boundary%20conditions&page=1">1</a></li> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=boundary%20conditions&page=2">2</a></li> <li class="page-item disabled"><span class="page-link">...</span></li> <li 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