Computers & Fluids最新文献

{"title":"Analysis and prediction of the pressure drop in corrugated plate heat exchangers based on numerical simulations","authors":"Nicolas Montiel ,&nbsp;Pierre Horgue ,&nbsp;Mathieu Courtial ,&nbsp;Benoît Sénéchal ,&nbsp;Julien Sebilleau ,&nbsp;Rémi Zamansky","doi":"10.1016/j.compfluid.2025.106910","DOIUrl":"10.1016/j.compfluid.2025.106910","url":null,"abstract":"<div><div>We present simulations of flows in wavy channels, typical of corrugated plated exchangers (CPHE), using wall-resolved Large Eddy Simulation (LES) and the Reynolds Average Navier-Stokes (RANS) approach with the <span><math><mrow><mi>k</mi><mo>−</mo><mi>ω</mi><mspace></mspace><mtext>SST</mtext></mrow></math></span> model. We consider three different corrugation angles (<em>β</em>) and a range of Reynolds numbers from 4721 to 47025. Using the LES, we analyze the evolution of the head loss across the CPHE and report that for moderate Re and <em>β</em> it is mainly caused by the wall-shear stress contribution, whereas at high Re and <em>β</em> it results from the wall-pressure contribution. Further wall-resolved LES simulations are used as a reference to assess and improve the quality of RANS modeling. The standard setting of the RANS <span><math><mrow><mi>k</mi><mo>−</mo><mi>ω</mi><mspace></mspace><mtext>SST</mtext></mrow></math></span> model, considered as a now-day standard for RANS in the industry, clearly showed limitations for such complicated geometries, with errors for the mean pressure drop prediction, which can be as high as 40 %. Finally we show that, relying on genetic algorithms, we can find sets of model parameters able to significantly reduce the RANS errors on the pressure drop although some discrepancies in the prediction of the mean flow structure remain, emphasizing the inherent limitation of the <span><math><mrow><mi>k</mi><mo>−</mo><mi>ω</mi><mspace></mspace><mtext>SST</mtext></mrow></math></span> model.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"305 ","pages":"Article 106910"},"PeriodicalIF":3.0,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570078","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 stochastic front tracking method for compressible flows with interfaces","authors":"Philippe Helluy ,&nbsp;Olivier Hurisse","doi":"10.1016/j.compfluid.2025.106888","DOIUrl":"10.1016/j.compfluid.2025.106888","url":null,"abstract":"<div><div>A front tracking method is proposed to deal with compressible flows involving sharp interfaces. It relies on a first-order finite-volumes scheme of Lagrange-Projection type. While the Lagrangian step of the method is classical, the projection step is based on a pseudo-random sampling technique in the spirit of the one used in the Glimm’s scheme. The scheme allows reducing the numerical diffusion at the interface, in the sense that they remain sharp. It has robustness and convergence properties that are not present in most of the schemes proposed previously, and it can be applied to unstructured meshes. While this new method works very well on structured meshes, improvements are still needed in order to achieve accurate results on unstructured meshes (triangles).</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"305 ","pages":"Article 106888"},"PeriodicalIF":3.0,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570124","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":"Actuator Line – Interpolated bounce back approach in lattice Boltzmann method for wind turbine wake simulation","authors":"Seiya Watanabe ,&nbsp;Hiroaki Kuranaga ,&nbsp;Changhong Hu","doi":"10.1016/j.compfluid.2025.106901","DOIUrl":"10.1016/j.compfluid.2025.106901","url":null,"abstract":"<div><div>Wind turbine wakes affect the power output of a wind farm. Unsteady turbulent simulations are a powerful approach to predicting turbine wake and wake loss in wind farms. This study proposes a novel wind turbine wake simulation based on an actuator line (AL) model for the lattice Boltzmann method. The standard AL model represents only blades, and the absence of turbine structures, such as a nacelle and a tower, impairs the precision of wake calculations. In this study, the interpolated bounce-back method, a wall boundary condition commonly used in the lattice Boltzmann method, represents a nacelle and a tower and is combined with the AL model. The proposed hybrid approach is validated by a stand-alone turbine calculation of the NTNU “Blind Test” 1. A mesh convergence study is conducted with five simulation cases at varying grid spacing, confirming that the results converge with a grid spacing of <em>D</em>/96 for the velocity deficit and <em>D</em>/128 for the turbulent kinetic energy, where the rotor diameter is <em>D</em>. Comparisons of simulations with and without modeling the nacelle and tower show that including the full turbine structure improves wake prediction accuracy. The proposed method is further evaluated against eight previous CFD studies that used blade-resolved or actuator-line models. The lattice Boltzmann simulations with the proposed turbine model reproduce the experimental wake profiles of mean velocity deficit and turbulent kinetic energy with accuracy comparable to these studies, except under stall-mode operation.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"305 ","pages":"Article 106901"},"PeriodicalIF":3.0,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570125","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":"Numerical relaxation techniques for mass transfer in three-phase liquid-vapor-gas flows","authors":"Marica Pelanti","doi":"10.1016/j.compfluid.2025.106893","DOIUrl":"10.1016/j.compfluid.2025.106893","url":null,"abstract":"<div><div>We describe liquid-vapor-gas flows by a hyperbolic single-velocity three-phase compressible flow model with instantaneous pressure relaxation that we studied in previous work. The model includes thermal relaxation terms to account for heat transfer, and chemical relaxation terms to describe mass transfer between the liquid and vapor phases. To numerically solve the model system we use a fractional step method where we alternate between the solution of the homogeneous system via finite volume HLLC-type schemes and the solution of systems of ordinary differential equations that take into account the relaxation source terms. In this work we propose a novel numerical procedure for chemical relaxation that can efficiently describe arbitrary-rate mass transfer, both slow finite-rate processes and stiff instantaneous ones. The main idea consists in describing the relaxation process by a system of ordinary differential equations that admits an analytical semi-exact exponential solution. This relaxation system is built by employing the relaxed models that can be derived analytically from the parent three-phase flow model in the limit of instantaneous mechanical and thermal relaxation processes, in order to guarantee the constraints of pressure and temperature equilibrium during phase transition. Some numerical experiments in one and two dimensions are presented to show the effectiveness of the proposed method.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"305 ","pages":"Article 106893"},"PeriodicalIF":3.0,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570081","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":"Calibration of Manning’s roughness coefficients for shallow-water flows on complex bathymetries using optimization algorithms and surrogate neural network models","authors":"Igor Gildas Metcheka Kengne ,&nbsp;Vincent Delmas ,&nbsp;Azzeddine Soulaïmani","doi":"10.1016/j.compfluid.2025.106884","DOIUrl":"10.1016/j.compfluid.2025.106884","url":null,"abstract":"<div><div>This paper presents an effective methodology for the automatic calibration of Manning’s roughness coefficients, which are crucial parameters for modeling shallow free-surface flows. Traditionally determined through empirical methods, these coefficients are subject to significant variability, making their determination challenging, especially in flow areas with complex bathymetry. The conventional trial-and-error approach, widely used to select these coefficients, is often tedious and time-consuming, particularly in applications constrained by time and data availability. The proposed methodology aims to determine the optimal values of Manning’s coefficients distributed over the flow domain while minimizing global discrepancies between simulations and field measurements. The calibration approach is formulated as an inverse optimization problem and addressed using metaheuristic optimization algorithms such as the Genetic Algorithm or Particle Swarm Optimization, combined with an ensemble model of deep neural networks. The database for training the neural networks is obtained using a newly developed finite volume-based shallow-water equations solver, parallelized on multiple GPUs, to generate large datasets of solutions for machine learning purposes. The performance of this approach is evaluated through various flow scenarios. Compared to conventional techniques, this methodology stands out for its simplicity, computational efficiency, and robustness. Additionally, Hybrid Particle Swarm Optimization (HPSO) proves to be particularly effective, notably for its speed. The developed codes are available at: <span><span>https://github.com/ETS-GRANIT/CuteFlow</span><svg><path></path></svg></span>.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"304 ","pages":"Article 106884"},"PeriodicalIF":3.0,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145464294","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":"Solving high Reynolds number flows on Cartesian cut-cell meshes using an ODE wall function with momentum balance","authors":"Alex Kleb,&nbsp;Krzysztof J. Fidkowski,&nbsp;Joaquim R.R.A. Martins","doi":"10.1016/j.compfluid.2025.106882","DOIUrl":"10.1016/j.compfluid.2025.106882","url":null,"abstract":"<div><div>Computational fluid dynamics is essential for designing aircraft, turbines, and other engineering systems. However, generating suitable computational meshes for complex geometries remains the primary bottleneck in analysis workflows, often requiring days of manual effort. Traditional boundary-conforming meshes excel at capturing near-wall physics in viscous flows but demand specialized expertise and extensive preprocessing time. Cartesian cut-cell methods provide automatic mesh generation for complex geometries in minutes, yet they struggle with high Reynolds number viscous flows where boundary layers exhibit rapid velocity changes that require prohibitively fine resolution for isotropic elements. The fundamental challenge is accurately modeling boundary layer physics on automatically generated meshes without sacrificing the computational efficiency that makes such methods attractive. In this work, we show that an ordinary differential equation (ODE) wall function incorporating pressure-momentum balance enables accurate high Reynolds number viscous flow predictions on coarse Cartesian cut-cell meshes. Our approach solves a one-dimensional boundary value problem at each wall boundary face that accounts for the transition from the viscous dominated near-wall region to the inviscid wake region, allowing forcing points to operate effectively at <span><math><mrow><msup><mi>y</mi><mo>+</mo></msup><mo>&gt;</mo><mn>600</mn></mrow></math></span>. Unlike traditional wall functions, the ODE is not limited to the logarithmic layer and maintains accuracy in strong pressure gradient environments typical of aerodynamic applications. The ODE can achieve correct skin friction predictions on meshes more than four times coarser than analytical wall functions require. The ODE wall functions are solved with a robust Newton–Krylov implementation that utilizes adaptive mesh refinement. It converges reliably across diverse flow conditions while solving hundreds of degrees of freedom in fewer than ten linear iterations. These results demonstrate that automatic high-fidelity viscous flow analysis is achievable without manual mesh generation expertise.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"304 ","pages":"Article 106882"},"PeriodicalIF":3.0,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145414647","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":"The Lax–Wendroff theorem for Patankar-type methods applied to hyperbolic conservation laws","authors":"Janina Bender ,&nbsp;Thomas Izgin ,&nbsp;Philipp Öffner ,&nbsp;Davide Torlo","doi":"10.1016/j.compfluid.2025.106885","DOIUrl":"10.1016/j.compfluid.2025.106885","url":null,"abstract":"<div><div>For hyperbolic conservation laws, the famous Lax–Wendroff theorem delivers sufficient conditions for the limit of a convergent numerical method to be a weak (entropy) solution. This theorem is a fundamental result, and many investigations have been done to verify its validity for finite difference, finite volume, and finite element schemes, using either explicit or implicit linear time-integration methods.</div><div>Recently, the use of modified Patankar (MP) schemes as time-integration methods for the discretization of hyperbolic conservation laws has gained increasing interest. These schemes are unconditionally conservative and positivity-preserving and only require the solution of a linear system. However, MP schemes are by construction nonlinear, which is why the theoretical investigation of these schemes is more involved. We prove an extension of the Lax–Wendroff theorem for the class of MP methods. This is the first extension of the Lax–Wendroff theorem to nonlinear time integration methods with just an additional hypothesis on the total time variation boundedness of the numerical solutions. We provide some numerical simulations that validate the theoretical observations.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"304 ","pages":"Article 106885"},"PeriodicalIF":3.0,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145414644","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":"Statistical model of turbulent flow of shear-thinning viscoplastic fluid with solid particles","authors":"A.A. Gavrilov ,&nbsp;A.V. Shebelev ,&nbsp;A.V. Minakov","doi":"10.1016/j.compfluid.2025.106878","DOIUrl":"10.1016/j.compfluid.2025.106878","url":null,"abstract":"<div><div>The paper presents the results of testing of a Eulerian model of two-phase turbulent non-Newtonian flow with coarse particles, proposed by the authors. The model includes equations for two-phase flow with rheological correlations and an equation for particle concentration transfer taking into account interfacial slip. The turbulence model takes into account the modulation of turbulence by particles. The proposed model has been validated on the problems of steady turbulent flow of shear thinning viscoplastic fluid with heavy particles in a horizontal pipe. The impact of Reynolds number and rheological parameters on the reliability of numerical simulations was examined. A comparison of experimental data with DNS-DEM simulation data has demonstrated that the proposed model is capable of accurately predicting the distribution of particle concentration, particle velocity, as well as carrier flow and pressure drop in the channel.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"304 ","pages":"Article 106878"},"PeriodicalIF":3.0,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145360933","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":"Characterizing drop morphology evolution in aerodynamic breakup with topological skeleton","authors":"S.G. Garcia,&nbsp;Y. Ling","doi":"10.1016/j.compfluid.2025.106894","DOIUrl":"10.1016/j.compfluid.2025.106894","url":null,"abstract":"<div><div>In the atomization and spray formation process, liquid structures undergo transient and complex deformation, making it challenging to characterize their morphological evolution. In the present study, a novel skeletonization method is presented to extract the topological skeleton for 2D and 3D liquid structures resolved by the Volume-of-Fluid (VOF) method. The maximally inscribed balls (MIB) within the reconstructed VOF surface are identified, and their resulting centers and radii consist of the topological skeleton. Due to numerical errors inherent in VOF-represented surfaces, erroneous skeleton points may arise. A filtering method is proposed to remove these skeleton points based on geometric properties. The skeletonization method is first tested using synthetic drop shapes composed of a superposition of spherical harmonic modes with different amplitudes. The number of skeleton branches is related to the mode number. The method is then applied to characterize the shape evolution of a drop in aerodynamic breakup. Both 2D axisymmetric and full 3D simulations are performed. The obtained curve and surface skeletons are useful for analyzing the morphological evolution of the drop and, more importantly, the sheet thickness distribution in the complex liquid bag.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"304 ","pages":"Article 106894"},"PeriodicalIF":3.0,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517554","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 of a spectral difference method for the diffused-interface five-equation model","authors":"Niccolò Tonicello ,&nbsp;Guido Lodato ,&nbsp;Matthias Ihme","doi":"10.1016/j.compfluid.2025.106880","DOIUrl":"10.1016/j.compfluid.2025.106880","url":null,"abstract":"<div><div>The present work focuses on the extension of the Spectral Difference (SD) scheme to the five-equation Baer-Nunziato model for the simulation of immiscible compressible fluids. This five-equation model is augmented with the Allen-Cahn regularisation to avoid both over-diffusion and over-thinning of the phase field representing the interface. In order to preserve contact discontinuities, in the reconstruction step of the SD scheme, a change of variables from conservative to primitive is used. This approach is shown to be beneficial in avoiding pressure oscillations at material interfaces. An extensive series of numerical tests, considering both two- and three-dimensional problems, are performed to assess accuracy and robustness of the present method. Specifically, both laminar and turbulent flows, as well as low-Mach and highly compressible flows, are considered, including cases with and without surface tension. The proposed change of variables is shown to improve the stability of the scheme, significantly reducing pressure oscillations at the material interfaces. This improved robustness enables the method to achieve accurate and stable solutions across a broad range of flow conditions.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"304 ","pages":"Article 106880"},"PeriodicalIF":3.0,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145414645","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}