International Journal for Numerical Methods in Fluids最新文献_第8页

Collocation Finite Element Method for the Fractional Fokker–Planck Equation 分数阶Fokker-Planck方程的配置有限元法

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-10-13 DOI: 10.1002/fld.5343

Hatice Karabenli, Alaattin Esen, Yusuf Uçar

{"title":"Collocation Finite Element Method for the Fractional Fokker–Planck Equation","authors":"Hatice Karabenli, Alaattin Esen, Yusuf Uçar","doi":"10.1002/fld.5343","DOIUrl":"https://doi.org/10.1002/fld.5343","url":null,"abstract":"In this study, the approximate results of the fractional Fokker–Planck equations have been investigated. First, finite element schemes have been obtained using collocation finite element method based on the trigonometric quintic B-spline basis functions. Then, the present method is tested on two fundamental problems having appropriate initial conditions. The newly obtained numerical results contained the error norms <math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>L</mi>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {L}_2 $$</annotation>\u0000 </semantics></math> and <math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>L</mi>\u0000 <mi>∞</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {L}_{infty } $$</annotation>\u0000 </semantics></math> for various temporal and spatial steps are compared with the exact ones and other solutions. More accurate results have been obtained for large numbers of spatial and temporal elements.","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 3","pages":"224-232"},"PeriodicalIF":1.7,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/fld.5343","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143114762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Robust 3D multi-material hydrodynamics using discontinuous Galerkin methods 基于不连续伽辽金方法的鲁棒三维多材料流体力学

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-10-08 DOI: 10.1002/fld.5340

Weizhao Li, Aditya Pandare, Hong Luo, Jozsef Bakosi, Jacob Waltz

{"title":"Robust 3D multi-material hydrodynamics using discontinuous Galerkin methods","authors":"Weizhao Li, Aditya Pandare, Hong Luo, Jozsef Bakosi, Jacob Waltz","doi":"10.1002/fld.5340","DOIUrl":"https://doi.org/10.1002/fld.5340","url":null,"abstract":"A high-order discontinuous Galerkin (DG) method is presented for nonequilibrium multi-material (<math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>m</mi>\u0000 <mo>≥</mo>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 <annotation>$$ mge 2 $$</annotation>\u0000 </semantics></math>) flow with sharp interfaces. Material interfaces are reconstructed using the algebraic THINC approach, resulting in a sharp interface resolution. The system assumes stiff velocity relaxation and pressure nonequilibrium. The presented DG method uses Dubiner's orthogonal basis functions on tetrahedral elements. This results in a unique combination of sharp multimaterial interfaces and high-order accurate solutions in smooth single-material regions. A novel shock indicator based on the interface conservation condition is introduced to mark regions with discontinuities. Slope limiting techniques are applied only in these regions so that nonphysical oscillations are eliminated while maintaining high-order accuracy in smooth regions. A local projection is applied on the limited solution to ensure discrete closure law preservation. The effectiveness of this novel limiting strategy is demonstrated for complex three-dimensional multi-material problems, where robustness of the method is critical. The presented numerical problems demonstrate that more accurate and efficient multi-material solutions can be obtained by the DG method, as compared to second-order finite volume methods.","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 2","pages":"188-209"},"PeriodicalIF":1.7,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/fld.5340","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143113182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Novel lattice Boltzmann method for simulation of strongly shear thinning viscoelastic fluids 模拟强剪切变薄粘弹性流体的新型晶格玻尔兹曼方法

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-10-08 DOI: 10.1002/fld.5335

Richard Kellnberger, Tomasz Jüngst, Stephan Gekle

引用次数: 0

A finite volume scheme employing the multipoint flux approximation with diamond stencil for the diffusive-viscous wave equation on general polyhedral meshes 一般多面体网格上扩散-粘性波动方程的菱形网格多点通量近似有限体积格式

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-10-07 DOI: 10.1002/fld.5336

Di Yang, Zhiming Gao, Wenjing Yan

引用次数: 0

Optimizing Winglet Cant Angle for Enhanced Aircraft Wing Performance Using CFD Simulation and Hybrid ANN-GA 基于CFD仿真和混合ANN-GA优化小翼夹角以提高飞机机翼性能

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-10-07 DOI: 10.1002/fld.5341

Vidhit Mandia, Vipul Sharma, Yash Chandra, Gaurav Kumar, Raj Kumar Singh

引用次数: 0

A volume-of-solid implicit volume penalty method for moving-body flows 运动体流的固体体积隐式体积惩罚法

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-09-19 DOI: 10.1002/fld.5334

Iason Tsetoglou, Mélody Cailler, Pierre Bénard, Ghislain Lartigue, Vincent Moureau, Julien Réveillon

{"title":"A volume-of-solid implicit volume penalty method for moving-body flows","authors":"Iason Tsetoglou, Mélody Cailler, Pierre Bénard, Ghislain Lartigue, Vincent Moureau, Julien Réveillon","doi":"10.1002/fld.5334","DOIUrl":"https://doi.org/10.1002/fld.5334","url":null,"abstract":"An original Immersed Boundary Method for solving moving body flows is proposed. This method couples (i) a Lagrangian Volume-of-Solid description of the solid object avoiding conservation issues and (ii) a robust implicit volume penalty forcing embedded in a low-Mach number projection method to account for the solid's impact on the fluid dynamics. A new composite velocity field is introduced to describe both solid and fluid domains in a single set of governing equations. The accuracy of the method has been assessed on several academic cases, involving stationary or moving bodies and with different mesh resolutions. The predicted forces on the solid are in excellent agreement with body-fitted reference cases. The system of equations is also proven to be fully mass conservative. Application of the method on a two-dimensional vertical axis turbine case shows a <math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>30</mn>\u0000 <mo>%</mo>\u0000 </mrow>\u0000 <annotation>$$ 30% $$</annotation>\u0000 </semantics></math> reduction in computational cost compared to a body-fitted method.","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 2","pages":"117-150"},"PeriodicalIF":1.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/fld.5334","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143117229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Semi-implicit Lagrangian Voronoi approximation for the incompressible Navier–Stokes equations 不可压缩纳维-斯托克斯方程的半隐式拉格朗日 Voronoi 近似法

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-09-17 DOI: 10.1002/fld.5339

Ondřej Kincl, Ilya Peshkov, Walter Boscheri

{"title":"Semi-implicit Lagrangian Voronoi approximation for the incompressible Navier–Stokes equations","authors":"Ondřej Kincl, Ilya Peshkov, Walter Boscheri","doi":"10.1002/fld.5339","DOIUrl":"10.1002/fld.5339","url":null,"abstract":"We introduce semi-implicit Lagrangian Voronoi approximation (SILVA), a novel numerical method for the solution of the incompressible Euler and Navier–Stokes equations, which combines the efficiency of semi-implicit time marching schemes with the robustness of time-dependent Voronoi tessellations. In SILVA, the numerical solution is stored at particles, which move with the fluid velocity and also play the role of the generators of the computational mesh. The Voronoi mesh is rapidly regenerated at each time step, allowing large deformations with topology changes. As opposed to the reconnection-based Arbitrary-Lagrangian-Eulerian schemes, we need no remapping stage. A semi-implicit scheme is devised in the context of moving Voronoi meshes to project the velocity field onto a divergence-free manifold. We validate SILVA by illustrative benchmarks, including viscous, inviscid, and multi-phase flows. Compared to its closest competitor, the Incompressible Smoothed Particle Hydrodynamics method, SILVA offers a sparser stiffness matrix and facilitates the implementation of no-slip and free-slip boundary conditions.","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 1","pages":"88-115"},"PeriodicalIF":1.7,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/fld.5339","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A new non-equilibrium modification of the k − ω $$ k-omega $$ turbulence model for supersonic turbulent flows with transverse jet 针对具有横向喷流的超音速湍流的 k-ω$$ k-omega $$ 湍流模型的新非平衡修正

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-09-17 DOI: 10.1002/fld.5337

Altynshash Naimanova, Assel Beketaeva

{"title":"A new non-equilibrium modification of the \u0000 \u0000 \u0000 k\u0000 −\u0000 ω\u0000 \u0000 $$ k-omega $$\u0000 turbulence model for supersonic turbulent flows with transverse jet","authors":"Altynshash Naimanova, Assel Beketaeva","doi":"10.1002/fld.5337","DOIUrl":"10.1002/fld.5337","url":null,"abstract":"The goal of this research is to propose a new modification of a non-equilibrium effect in the <math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>k</mi>\u0000 <mo>−</mo>\u0000 <mi>ω</mi>\u0000 </mrow>\u0000 <annotation>$$ k-omega $$</annotation>\u0000 </semantics></math> turbulence model to better predict high-speed turbulent flows. For that, the two local compressibility coefficients are included in the balance production/dissipation terms in a specific dissipation rate equation. The specific dissipation rate reacts to changes in the local Mach number and density through these local coefficients. The developed model is applied to the numerical simulation of the spatial supersonic turbulent airflow with round hydrogen injection. In that, the effects of the proposed turbulence model on the flow field behavior (shock wave and vortex formations, shock wave/boundary layer interaction, and mixture layer) are studied via the solution of three-dimensional Favre-averaged Navier–Stokes equations with a third-order Essentially Non-Oscillatory scheme. A series of numerical experiments are performed, in which an allowable range of local constants by comparing results with experimental data is obtained. The non-equilibrium modification by simultaneous decrease of the turbulence kinetic energy and increase of the specific dissipation rate gives a good agreement of the hydrogen depth penetration with experimental data. Also, the numerical experiment of the supersonic airflow with a nitrogen jet shows wall pressure distribution is consistent well with experimental data.","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 1","pages":"69-87"},"PeriodicalIF":1.7,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Turbulence effects in the topology optimization of compressible subsonic flow 可压缩亚音速流拓扑优化中的湍流效应

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-09-16 DOI: 10.1002/fld.5338

Luis Fernando Garcia-Rodriguez, Diego Hayashi Alonso, Emilio Carlos Nelli Silva

{"title":"Turbulence effects in the topology optimization of compressible subsonic flow","authors":"Luis Fernando Garcia-Rodriguez, Diego Hayashi Alonso, Emilio Carlos Nelli Silva","doi":"10.1002/fld.5338","DOIUrl":"https://doi.org/10.1002/fld.5338","url":null,"abstract":"Turbulence significantly influences fluid flow topology optimization, and this has already been verified under the incompressible flow regime. However, the same cannot be said about the compressible flow regime, in which the density field now affects and couples all of the fluid flow and turbulence equations and makes obtaining the adjoint model, which is necessary for topology optimization, extremely difficult. Up to now, the turbulence phenomenon has still not been considered in compressible flow topology optimization, which is what is being proposed and analyzed here. Rather than being based in the Reynolds-Averaged Navier–Stokes (RANS) equations which are defined only for incompressible flow, the equations are now based on the Favre-Averaged Navier–Stokes (FANS) equations, which are the counterpart of the RANS equations for compressible flow and feature different dependencies and terms. The compressible turbulence model being considered is the compressible version of the Spalart–Allmaras model, which differs from the usual Spalart–Allmaras model, since now there are some new spatially varying density and specific heat terms that depend on the primal variables and that act over some of the turbulence terms of the overall model. The adjoint equations are obtained by using an automatic differentiation scheme through a coupled software platform. The optimization algorithm is IPOPT, and some examples are presented to show the effect of turbulence in the compressible flow topology optimization.","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 1","pages":"44-68"},"PeriodicalIF":1.7,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142759838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Response surface method-based hydraulic performance optimization of a single-stage centrifugal pump 基于响应面法的单级离心泵水力性能优化

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-09-07 DOI: 10.1002/fld.5332

Durvesh Yadav, Raj Kumar Singh, K. Manjunath

{"title":"Response surface method-based hydraulic performance optimization of a single-stage centrifugal pump","authors":"Durvesh Yadav, Raj Kumar Singh, K. Manjunath","doi":"10.1002/fld.5332","DOIUrl":"10.1002/fld.5332","url":null,"abstract":"In this article, the response surface approach was employed to enhance the hydraulic performance of the pump at the rated point. Specifically, an approximate link between the design head and efficiency of the single-stage centrifugal pump and the parameters of the impeller's design was established. The first step in creating a one-factor experimental design involved selecting significant geometric variables as factors. Decision variables such as the number of blades, flow rate, and rotation were chosen due to their significant impact on hydraulic performance, while head and efficiency were considered as responses. Subsequently, the best-optimized values for each level of the parameters were identified using response surface analysis and a central composite design. The impeller schemes of the Design-Expert software were evaluated for head and efficiency using Computational fluid dynamics, and a total of 20 experiments were conducted. The simulated results were then validated with experimental data. Through the analysis of the individual parameters and the approximation model, the ideal parameter combination that increased head and efficiency by 7.90% and 2.06%, respectively, at the rated value was discovered. It is worth noting that in cases of a high rate of flow, the inner flow was also enhanced.","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 1","pages":"20-43"},"PeriodicalIF":1.7,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0