Computers & Fluids最新文献

{"title":"Discontinuous Galerkin spectral element method with hybrid sub-element order reduction for shock-capturing with Navier–Stokes equations","authors":"Fengrui Zhang,&nbsp;Yulia T. Peet","doi":"10.1016/j.compfluid.2025.106650","DOIUrl":"10.1016/j.compfluid.2025.106650","url":null,"abstract":"<div><div>The current study presents a high-order methodology for the simulation of three-dimensional compressible viscous flows with shocks in complex geometries. The method is developed based on the framework of a split-form discontinuous Galerkin spectral element method (DGSEM) with summation-by-parts (SBP) operators. The Bassi and Rebay (Bassi and Rebay, 1997) (BR1) scheme is employed for the discretization of the viscous terms. For shock capturing, a hybrid sub-element order reduction methodology is developed which is based on a mixed functional space that blends high-order polynomial basis functions with piecewise-constant functions supported on sub-element volumes. An amount of blending is determined based on a modified Ducros indicator which has excellent shock detecting capabilities in viscous turbulent flows. The performance of the methodology is demonstrated on the example of eight test cases, featuring 1D, 2D and 3D inviscid and viscous flows with and without shocks.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"297 ","pages":"Article 106650"},"PeriodicalIF":2.5,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143943231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Embedded LES of a turbulent thermal boundary layer over ice roughness","authors":"Denis Sotomayor-Zakharov ,&nbsp;Riccardo Gaudioso ,&nbsp;Mariachiara Gallia","doi":"10.1016/j.compfluid.2025.106652","DOIUrl":"10.1016/j.compfluid.2025.106652","url":null,"abstract":"<div><div>The numerical prediction of ice accretion via icing codes relies on the proper estimation of the heat transfer coefficient on rough ice geometries. To understand the heat transfer physics at play, direct numerical simulations (DNS) on rough surfaces can be performed, although this results in a very expensive option if geometries obtained from different icing conditions want to be analyzed. Large eddy simulation (LES) presents itself as a less expensive option to perform such studies, giving insight into the physics of turbulence, as well as opening the possibility for calibration of roughness models. The present study verifies and validates a setup to perform embedded LES (ELES) of a zero pressure gradient incompressible flow over a flat plate with ice roughness heated to a constant wall temperature. An experimental database is used, which provides the geometries of rough plates obtained from unwrapped scans of ice shapes generated on a NACA0012 airfoil. The low-speed flow over the flat plate presents a <span><math><mrow><mi>R</mi><msub><mrow><mi>e</mi></mrow><mrow><mi>L</mi></mrow></msub><mo>=</mo><mn>3</mn><mo>.</mo><mn>85</mn><mi>⋅</mi><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>5</mn></mrow></msup></mrow></math></span> and <span><math><mrow><mi>P</mi><mi>r</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>729</mn></mrow></math></span>. The verification is carried out by analyzing the effects of the mesh resolution and the domain span on wall properties such as the skin friction coefficient and Stanton number. Additionally, an analysis of turbulence-related flow statistics is performed to guarantee the proper development of turbulence. The validation shows good agreement between ELES results and experimental data, especially for the Stanton number distributions, showcasing that this setup can be used for the study of heat transfer on ice roughness.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"297 ","pages":"Article 106652"},"PeriodicalIF":2.5,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143917772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extension to non-uniform meshes of a high order computationally explicit kinetic scheme for hyperbolic conservation laws","authors":"Rémi Abgrall ,&nbsp;Stéphane Del Pino ,&nbsp;Axelle Drouard ,&nbsp;Emmanuel Labourasse","doi":"10.1016/j.compfluid.2025.106648","DOIUrl":"10.1016/j.compfluid.2025.106648","url":null,"abstract":"<div><div>In this paper, we present an extension to non-uniform meshes of a 1D scheme [Rémi Abgrall and Davide Torlo. “Some preliminary results on a high order asymptotic preserving computationally explicit kinetic scheme”. In: <em>Abgrall and Torlo (2022)</em>. This scheme is arbitrary high order convergent in space and time for any hyperbolic system of conservation laws. It is based on a Finite Difference technique. We show that this numerical method is not conservative but it satisfies a Lax–Wendroff theorem under restrictive conditions on the mesh. To relax this condition we propose a Finite Volume alternative. This new discretization can be seen as a direct generalization to non-uniform meshes of the Finite Difference schemes in the sense that the fluxes of both methods are the same on uniform meshes. We apply the two schemes to the Euler system and we assess their performances on regarding test problems of the literature.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"297 ","pages":"Article 106648"},"PeriodicalIF":2.5,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143943232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vortex-Induced Vibrations of in-line cantilevered cylinders","authors":"M.M.M.D. Hussain ,&nbsp;K. Zwijsen ,&nbsp;A.H. van Zuijlen","doi":"10.1016/j.compfluid.2025.106647","DOIUrl":"10.1016/j.compfluid.2025.106647","url":null,"abstract":"<div><div>The advent of global warming has brought an increased interest in non-conventional sources of energy, one of which is nuclear energy. Threatening the almost year-round functioning of nuclear power plants are Flow-Induced Vibrations (FIV). One mechanism of FIV, Vortex-Induced Vibration (VIV), holds importance in areas of cross-flow in nuclear power plants where lock-in occurs. To make safe-life designs, computational analysis in the domain of Fluid-Structure Interactions (FSI) has been increasing over the past two decades. This article aims to add to the body of knowledge by making predictions for an in-line two-cylinder configuration, set up as part of a benchmark proposed by the Nuclear Energy Agency (NEA) of the Organization for Economic Co-operation and Development (OECD), using the commercial code <em>Simcenter STAR-CCM+ (V2020.3.1)</em>.</div><div>The main objective of this study is to test the efficacy of the URANS framework in predicting VIV, which is connected with the objective of the OECD/NEA to propose recommendations for the <em>Best Practice Guidelines</em>. The benchmark was structured in two phases: the open phase where the experimental results were available to the benchmark participants a priori and the blind phase where the experimental results, with cylinders having different natural frequencies than that of the open phase, were released to the benchmark participants only after all computational results were submitted to the OECD/NEA. The open phase was used to test 3 turbulence models, namely ‘K-<span><math><mi>ω</mi></math></span> SST: Quadratic’, ‘K-<span><math><mi>ω</mi></math></span> SST: Quadratic + GRT transition’ and ‘Standard K-<span><math><mi>ϵ</mi></math></span> Low Re: Cubic’ in order to choose the most appropriate model for the blind phase. Key results from this study revealed the ‘Standard K-<span><math><mi>ϵ</mi></math></span> Low Re: Cubic’ model to be the most apt for the benchmark. Furthermore, gaps are also identified in the application of URANS to predict VIV resonance conditions, namely the overprediction of the vortex shedding frequency, adoption of inflow turbulence and the underprediction of high frequency range spectra.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"297 ","pages":"Article 106647"},"PeriodicalIF":2.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143924504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the convection boundedness of numerical schemes across discontinuities","authors":"Xi Deng ,&nbsp;Zhen-hua Jiang ,&nbsp;Omar K. Matar ,&nbsp;Chao Yan","doi":"10.1016/j.compfluid.2025.106645","DOIUrl":"10.1016/j.compfluid.2025.106645","url":null,"abstract":"<div><div>This short note introduces a novel diagnostic tool for evaluating the convection boundedness properties of numerical schemes across discontinuities. The proposed method is based on the convection boundedness criterion and the normalised variable diagram. By utilising this tool, we can determine the CFL conditions for numerical schemes to satisfy the convection boundedness criterion, identify the locations of over- and under-shoots, optimise the free parameters in the schemes, and develop strategies to prevent numerical oscillations across the discontinuity. We apply the diagnostic tool to assess representative discontinuity-capturing schemes, including THINC, fifth-order WENO, and fifth-order TENO, and validate the conclusions drawn through numerical tests. We further demonstrate the application of the proposed method by formulating a new THINC scheme with less stringent CFL conditions.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"296 ","pages":"Article 106645"},"PeriodicalIF":2.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143902576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using lateral dispersion to optimise microfluidic trap array efficiency","authors":"Nicolas Ruyssen ,&nbsp;Gabriel Fina ,&nbsp;Rachele Allena ,&nbsp;Marie-Caroline Jullien ,&nbsp;Jacques Fattaccioli","doi":"10.1016/j.compfluid.2025.106643","DOIUrl":"10.1016/j.compfluid.2025.106643","url":null,"abstract":"<div><div>Microfluidic trapping arrays have proven to be efficient tools for various applications that require working at the single-cell level, such as cell–cell communication or fusion. Although several hydrodynamic trapping devices have already been optimised, two-dimensional (2D) single-layer trapping arrays with high trap densities remain partially inefficient. Specifically, many traps remain empty, even after prolonged injection, which drastically reduces the number of samples available for post-treatment. These unfilled traps result from the symmetrical nature of the flow around the traps, and breaking this symmetry enhances capture efficiency. In this study, we use a numerical approach to show that optimal geometries can significantly increase filling efficiency and a preliminary experimental test confirming our approach is provided. We show that these improvements are achieved by promoting lateral dispersion of particles, facilitated either through an optimised oblique flow or by introducing disorder into the spatial arrangement of traps without specific inlet/outlet adjustment.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"297 ","pages":"Article 106643"},"PeriodicalIF":2.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143931515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Approximate well-balanced WENO finite difference schemes using a global-flux quadrature method with multi-step ODE integrator weights","authors":"M. Kazolea ,&nbsp;C. Parés ,&nbsp;M. Ricchiuto","doi":"10.1016/j.compfluid.2025.106646","DOIUrl":"10.1016/j.compfluid.2025.106646","url":null,"abstract":"<div><div>In this work, high-order discrete well-balanced methods for one-dimensional hyperbolic systems of balance laws are proposed. We aim to construct a method whose discrete steady states correspond to solutions of arbitrary high-order ODE integrators. However, this property is embedded directly into the scheme, eliminating the need to apply the ODE integrator explicitly to solve the local Cauchy problem.</div><div>To achieve this, we employ a WENO finite difference framework and apply WENO reconstruction to a global flux assembled nodewise as the sum of the physical flux and a source primitive. The novel idea is to compute the source primitive using high-order multi-step ODE methods applied on the finite difference grid. This approach provides a locally well-balanced splitting of the source integral, with weights derived from the ODE integrator. By construction, the discrete solutions of the proposed schemes align with those of the underlying ODE integrator.</div><div>The proposed methods employ WENO flux reconstructions of varying orders, combined with multi-step ODE methods of up to order 8, achieving steady-state accuracy determined solely by the ODE method’s consistency. Numerical experiments using scalar balance laws and shallow water equations confirm that the methods achieve optimal convergence for time-dependent solutions and significant error reduction for steady-state solutions.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"296 ","pages":"Article 106646"},"PeriodicalIF":2.5,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel finite volume method with Walsh basis function and its multigrid features","authors":"Yuan Gan ,&nbsp;Gang Wang ,&nbsp;Jiong Ren","doi":"10.1016/j.compfluid.2025.106663","DOIUrl":"10.1016/j.compfluid.2025.106663","url":null,"abstract":"<div><div>In previous work, the authors published a novel numerical method capable of capturing discontinuities (e.g., shock waves) for 1D problems within the grid cell (Ren &amp; Wang, 2020), which is called the Finite Volume Method with Walsh Basis Functions (FVM-WBF). In the FVM-WBF method, the conservative variables within a grid cell are expressed in the expansion form of the WBF series. By extending this series, the accuracy of capturing discontinuities can be significantly improved. However, this method does result in a significant increase in computational cost, especially for high-dimensional problems. In this paper, the FVM-WBF method is extended to 2D and 3D cases. Additionally, to address the efficiency issues, an innovative multigrid approach is proposed to enhance the computational efficiency of this method. Following an analysis of the WBFs, it was found that there are spatial scales in the expression of different WBF series within the grid cell, which is similar to different grid levels in <em>h</em>-multigrid method. Based on this finding, a simple and efficient multigrid algorithm is devised and implemented in the FVM-WBF method. This multigrid algorithm has advantages over the classical <em>h</em>-multigrid implementation in that it does not require interpolation/constraint operators or transferring information between different grid hierarchies, and the computational efficiency can be significantly improved only by adopting the time step size based on spatial scales without increasing the computational cost at each iteration. Several test cases are presented and the results show that the computational efficiency of the proposed method can be effectively improved.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"297 ","pages":"Article 106663"},"PeriodicalIF":2.5,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143907006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Achieving rapid convergence in false-transient RANS simulations on unstructured meshes using an implicit adaptive time stepping method","authors":"M.R. Nived ,&nbsp;Nikhil Narayan Kalkote ,&nbsp;Vinayak Eswaran","doi":"10.1016/j.compfluid.2025.106644","DOIUrl":"10.1016/j.compfluid.2025.106644","url":null,"abstract":"<div><div>A variable time-step algorithm based on the second-order backward differentiation formula (BDF2) for rapidly changing time steps is applied to false-transient simulations of stationary turbulent flow solutions to obtain rapid convergence to steady-state. This adaptive time stepping (ATS) algorithm imposes a user-defined tolerance limit on the local truncation error to estimate the maximum allowable time-step size for pseudo-time marching. It can be readily integrated into any pre-existing implicit flow solver. The algorithm is incorporated into a parallel implicit compressible flow solver that uses the block LUSGS method to compute solutions of linear systems on unstructured grids. The ATS solver is verified using test cases of incompressible flow over a flat plate and a NACA-0012 airfoil near stall to showcase its capability to produce rapid convergence to machine precision even on high aspect ratio meshes. The ATS algorithm reduces overall simulation times by factors of 100-200 times compared to constant CFL time-stepping, even in the case of transonic flow over an <em>Onera M6</em> wing. Its performance against a few basic CFL laws is also shown to be good and a thorough comparison with competing methods will be undertaken later. The adaptive implicit algorithm is also deployed to simulate transonic flow over a <em>DLR-F6</em> aircraft wing body configuration with/without nacelle and pylon, demonstrating its application in practical aircraft design.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"296 ","pages":"Article 106644"},"PeriodicalIF":2.5,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143892038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A positivity-preserving approach for implicit dual-time stepping schemes in multi-component flow simulations","authors":"Hongmin Su,&nbsp;Pengxin Liu,&nbsp;Xianxu Yuan,&nbsp;Bo Li,&nbsp;Qilong Guo","doi":"10.1016/j.compfluid.2025.106629","DOIUrl":"10.1016/j.compfluid.2025.106629","url":null,"abstract":"<div><div>The implicit dual-time stepping schemes are very efficient in solving the multi-component flows with a time scale discrepancy induced by the chemical reactions. However, high-order accurate simulations often fail to obtain a converged result due to non-positive density or pressure during computations. In this paper, we deduce a sufficient condition for positivity-preserving of the dual-time stepping scheme with explicit pseudo-time and implicit physical time stepping, which allows a simple and efficient positivity-preserving flux limiter by the weight average of Lax–Friedrichs and high-order numerical fluxes. This flux limiter requires less time restriction than the earlier positivity-preserving strategy, implying a higher computational efficiency. In addition, it only introduces minor changes in the eigenvalues for the high-order numerical fluxes when projected to conservative variables, retaining the accuracy of the numerical fluxes to the greatest extent possible. This approach can be applied equally to the implicit dual-time stepping scheme because the solution will be positivity-preserving when converged sufficiently. Various validations computed by the fifth-order WENOZ and second-order Runge–Kutta scheme indicate that the present positivity-preserving algorithm possesses an excellent capability of simulating multi-component flows with strong discontinuities accurately and efficiently.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"297 ","pages":"Article 106629"},"PeriodicalIF":2.5,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143928207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}