International Journal for Numerical Methods in Fluids最新文献

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 1.8 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-09-18 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":"https://doi.org/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":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","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":"","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 1.8 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 k−ω$$ k-omega $$ turbulence model for supersonic turbulent flows with transverse jet","authors":"Altynshash Naimanova, Assel Beketaeva","doi":"10.1002/fld.5337","DOIUrl":"https://doi.org/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 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":null,"pages":null},"PeriodicalIF":1.8,"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

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 1.8 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":"https://doi.org/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":null,"pages":null},"PeriodicalIF":1.8,"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

Development of a new solver for homogenous mixture based on regularized gas dynamic equation system 基于正则化气体动力方程系统开发新的均质混合物求解器

IF 1.8 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-09-06 DOI: 10.1002/fld.5333

Andrey Epikhin, Ivan But

引用次数: 0

Monolithic finite element modeling of compressible fluid-structure-electrostatics interactions in MEMS devices 微机电系统设备中可压缩流体-结构-静电相互作用的整体有限元建模

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-08-30 DOI: 10.1002/fld.5329

Suman Dutta, C. S. Jog

{"title":"Monolithic finite element modeling of compressible fluid-structure-electrostatics interactions in MEMS devices","authors":"Suman Dutta, C. S. Jog","doi":"10.1002/fld.5329","DOIUrl":"10.1002/fld.5329","url":null,"abstract":"This work presents a monolithic finite element strategy for the accurate solution of strongly-coupled fluid-structure-electrostatics interaction problems involving a compressible fluid. The complete set of equations for a compressible fluid is employed within the framework of the arbitrary Lagrangian–Eulerian (ALE) fluid formulation on the reference configuration. The proposed numerical approach incorporates geometric nonlinearities of both the structural and fluid domains, and can thus be used for investigating dynamic pull-in phenomena and squeeze film damping in high aspect-ratio micro-electro-mechanical systems (MEMS) structures immersed in a compressible fluid. Through various illustrative examples, we demonstrate the significant influence of fluid compressibility on the dynamics of MEMS devices subjected to constrained geometry and/or high-frequency electrostatic actuation. Moreover, we compare the proposed formulation with the nonlinear compressible Reynolds equation and highlight that, particularly at low pressures and high fluid viscosity, the Reynolds equation fails to provide a reliable approximation to the complete set of equations utilized in our proposed formulation.","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223829","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

Discrete strong extremum principles for finite element solutions of advection-diffusion problems with nonlinear corrections 具有非线性修正的平流扩散问题有限元解的离散强极值原理

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-08-28 DOI: 10.1002/fld.5330

Shuai Wang, Guangwei Yuan

{"title":"Discrete strong extremum principles for finite element solutions of advection-diffusion problems with nonlinear corrections","authors":"Shuai Wang, Guangwei Yuan","doi":"10.1002/fld.5330","DOIUrl":"10.1002/fld.5330","url":null,"abstract":"A nonlinear correction technique for finite element methods of advection-diffusion problems on general triangular meshes is introduced. The classic linear finite element method is modified, and the resulting scheme satisfies discrete strong extremum principle unconditionally, which means that it is unnecessary to impose the well-known restrictions on diffusion coefficients and geometry of mesh-cell (e.g., “acute angle” condition), and we need not to perform upwind treatment on the advection term separately. Moreover, numerical example shows that when a discrete scheme does not satisfy the strong extremum principle, even if it maintains the global physical bound, non-physical numerical oscillations may still occur within local regions where no numerical result is beyond the physical bound. Thus, it is worth to point out that our new nonlinear finite element scheme can avoid non-physical oscillations around sharp layers in advection-dominate regions, due to maintaining discrete strong extremum principle. Convergence rates are verified by numerical tests for both diffusion-dominate and advection-dominate problems.","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183623","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

A high-order pure streamfunction method in general curvilinear coordinates for unsteady incompressible viscous flow with complex geometry 一般曲线坐标下的高阶纯流函数法，用于具有复杂几何形状的非稳态不可压缩粘性流动

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-08-26 DOI: 10.1002/fld.5331

Bo Wang, Peixiang Yu, Xin Tong, Hua Ouyang

{"title":"A high-order pure streamfunction method in general curvilinear coordinates for unsteady incompressible viscous flow with complex geometry","authors":"Bo Wang, Peixiang Yu, Xin Tong, Hua Ouyang","doi":"10.1002/fld.5331","DOIUrl":"10.1002/fld.5331","url":null,"abstract":"In this paper, a high-order compact finite difference method in general curvilinear coordinates is proposed for solving unsteady incompressible Navier-Stokes equations. By constructing the fourth-order spatial discretization schemes for all partial derivative terms of the pure streamfunction formulation in general curvilinear coordinates, especially for the fourth-order mixed derivative terms, and applying a Crank-Nicolson scheme for the second-order temporal discretization, we extend the unsteady high-order pure streamfunction algorithm to flow problems with more general non-conformal grids. Furthermore, the stability of the newly proposed method for the linear model is validated by von-Neumann linear stability analysis. Five numerical experiments are conducted to verify the accuracy and robustness of the proposed method. The results show that our method not only effectively solves problems with non-conformal grids, but also allows grid generation and local refinement using commercial software. The solutions are in good agreement with the established numerical and experimental results.","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183622","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

An implicit DG solver for incompressible two-phase flows with an artificial compressibility formulation 采用人工可压缩性公式的不可压缩两相流隐式 DG 求解器

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-08-19 DOI: 10.1002/fld.5328

Giuseppe Orlando

引用次数: 0

A local and hierarchical Koopman spectral analysis of fluid dynamics 流体动力学的局部和分层库普曼谱分析

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-08-05 DOI: 10.1002/fld.5327

Wei Zhang, Mingjun Wei

{"title":"A local and hierarchical Koopman spectral analysis of fluid dynamics","authors":"Wei Zhang, Mingjun Wei","doi":"10.1002/fld.5327","DOIUrl":"10.1002/fld.5327","url":null,"abstract":"A local and hierarchical Koopman spectral analysis is proposed to extend Koopman spectral analysis typically used in a linear system or an ergodic process to its application in general nonlinear dynamics. The continuous and analytic Koopman eigenfunctions and eigenvalues, derived from operator perturbation theory, are capable of dealing with a nonlinear transition process with mathematical rigorousness. A proliferation rule is identified to derive high-order eigenvalues and eigenfunctions from lower-order ones, thus various spectral patterns may be generated through recursive proliferations. The locally linear map around each state constructs base local Koopman eigenvalues and eigenfunctions from an algebraic eigenvalue problem, and high-order ones are generated via the proliferation rule to express the systematic nonlinearity. The aforementioned hierarchy simplifies the Koopman spectral analysis and is verified by studying the development of Kármán vortex streets. The triangular chain and the lattice distribution of Koopman eigenvalues confirm the critical role of the proliferation rule and the hierarchy structure of Koopman eigenvalues. The local spectral analysis on the transition process shows that the periodic flow forms as the growth rates of the critical Koopman modes reduce to zero, and meanwhile, the Koopman modes at the same frequency superpose on each other to form the well-known Fourier or Floquet modes, where the latter are the enhanced nonlinear motions due to the alignment of Koopman eigenvalues with the critical ones.","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141941433","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

Stability of a continuous/discrete sensitivity model for the Navier–Stokes equations 纳维-斯托克斯方程连续/离散敏感性模型的稳定性

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-08-05 DOI: 10.1002/fld.5324

N. Nouaime, B. Després, M. A. Puscas, C. Fiorini

引用次数: 0