This work extends the Nodal Integral-Immersed Boundary Method (NIM-IBM) to the solution of steady incompressible Navier-Stokes equations in complex geometries. The NIM provides a coarse-mesh, semi-analytical discretization that maintains second-order spatial accuracy, while the sharp-interface IBM enforces boundary conditions on non-body-fitted Cartesian grids. To address the challenges of pressure-velocity coupling and mass conservation near immersed boundaries, the formulation integrates a hybrid MAC-SOLA (Marker and Cell-Solution Algorithm) pressure-correction scheme, preserving the analytical structure of NIM and avoiding complex matrix couplings at cut cells. The proposed framework is validated against multiple benchmark problems involving internal and external flows. Results show that the method accurately captures key flow features and benchmark quantities, even on coarse meshes, with good agreement to experimental and high-resolution numerical data. The approach offers a computationally efficient and geometrically flexible alternative for incompressible flow simulations, with potential for extension to unsteady and high-Reynolds-number regimes.
{"title":"A coarse-mesh semi-analytical framework for incompressible flows: Extending the Nodal Integral-Immersed Boundary Method","authors":"Amritpal Singh , Neeraj Kumar , Abdellah Hadjadj , Mostafa Safdari Shadloo","doi":"10.1016/j.compfluid.2026.106967","DOIUrl":"10.1016/j.compfluid.2026.106967","url":null,"abstract":"<div><div>This work extends the Nodal Integral-Immersed Boundary Method (NIM-IBM) to the solution of steady incompressible Navier-Stokes equations in complex geometries. The NIM provides a coarse-mesh, semi-analytical discretization that maintains second-order spatial accuracy, while the sharp-interface IBM enforces boundary conditions on non-body-fitted Cartesian grids. To address the challenges of pressure-velocity coupling and mass conservation near immersed boundaries, the formulation integrates a hybrid MAC-SOLA (Marker and Cell-Solution Algorithm) pressure-correction scheme, preserving the analytical structure of NIM and avoiding complex matrix couplings at cut cells. The proposed framework is validated against multiple benchmark problems involving internal and external flows. Results show that the method accurately captures key flow features and benchmark quantities, even on coarse meshes, with good agreement to experimental and high-resolution numerical data. The approach offers a computationally efficient and geometrically flexible alternative for incompressible flow simulations, with potential for extension to unsteady and high-Reynolds-number regimes.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"307 ","pages":"Article 106967"},"PeriodicalIF":3.0,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940525","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}
Pub Date : 2026-01-07DOI: 10.1016/j.compfluid.2026.106968
Thomas S. Chyczewski, David A. Boger, Norman F. Foster
Large-eddy simulations (LESs) of homogeneous, initially isotropic turbulence decaying in a stratified environment were performed using an isotropic sub-grid scale model and compared to previously reported direct numerical simulation (DNS) results. The evolution of potential and kinetic energy, as well as key similarity parameters dependent on velocity fluctuations, turbulent kinetic energy dissipation rate, and turbulence length scales, were analyzed to assess the performance of the model in a stratified flow where anisotropy extends to very small scales. Favorable agreement between LES and DNS results was found, despite the Ozmidov scale, which characterizes the size of the smallest anisotropic eddies, not being resolved and the buoyancy length scale, at which buoyancy-induced Kelvin-Helmholtz instabilities develop, being marginally resolved.
{"title":"Large-eddy simulation of decaying stratified turbulence","authors":"Thomas S. Chyczewski, David A. Boger, Norman F. Foster","doi":"10.1016/j.compfluid.2026.106968","DOIUrl":"10.1016/j.compfluid.2026.106968","url":null,"abstract":"<div><div>Large-eddy simulations (LESs) of homogeneous, initially isotropic turbulence decaying in a stratified environment were performed using an isotropic sub-grid scale model and compared to previously reported direct numerical simulation (DNS) results. The evolution of potential and kinetic energy, as well as key similarity parameters dependent on velocity fluctuations, turbulent kinetic energy dissipation rate, and turbulence length scales, were analyzed to assess the performance of the model in a stratified flow where anisotropy extends to very small scales. Favorable agreement between LES and DNS results was found, despite the Ozmidov scale, which characterizes the size of the smallest anisotropic eddies, not being resolved and the buoyancy length scale, at which buoyancy-induced Kelvin-Helmholtz instabilities develop, being marginally resolved.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"307 ","pages":"Article 106968"},"PeriodicalIF":3.0,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974154","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}
Pub Date : 2026-01-06DOI: 10.1016/j.compfluid.2026.106959
Philipp Spelten , Dominik Wilde , Mario Christopher Bedrunka , Dirk Reith , Holger Foysi
Lattice Boltzmann method (LBM) simulations of incompressible flows are nowadays common and well established. However, compressible supersonic flows with strong variable density and intrinsic compressibility effects pose particular challenges and are subject to ongoing research. The recently developed semi-Lagrangian lattice Boltzmann method (SLLBM) is capable of simulating two- and three-dimensional viscous compressible supersonic flows. This paper presents bounce-back, thermal, inlet, and outlet boundary conditions new to the method and their application to problems including heated or cooled walls, often required for supersonic flow cases. Using these boundary conditions, the SLLBM’s capabilities are demonstrated in various test cases, including a supersonic 2D NACA-0012 airfoil, flow around a 3D sphere, and, to the best of our knowledge, for the first time using an LBM, the 3D simulation of a supersonic turbulent channel flow at a bulk Mach number of and a 3D temporal supersonic compressible mixing layer at convective Mach numbers ranging from to . The results show that the compressible SLLBM is able to adequately capture intrinsic and variable density compressibility effects.
{"title":"Supersonic shear and wall-bounded flows with body-fitted meshes using the semi-Lagrangian lattice Boltzmann method: Boundary schemes and applications","authors":"Philipp Spelten , Dominik Wilde , Mario Christopher Bedrunka , Dirk Reith , Holger Foysi","doi":"10.1016/j.compfluid.2026.106959","DOIUrl":"10.1016/j.compfluid.2026.106959","url":null,"abstract":"<div><div>Lattice Boltzmann method (LBM) simulations of incompressible flows are nowadays common and well established. However, compressible supersonic flows with strong variable density and intrinsic compressibility effects pose particular challenges and are subject to ongoing research. The recently developed semi-Lagrangian lattice Boltzmann method (SLLBM) is capable of simulating two- and three-dimensional viscous compressible supersonic flows. This paper presents bounce-back, thermal, inlet, and outlet boundary conditions new to the method and their application to problems including heated or cooled walls, often required for supersonic flow cases. Using these boundary conditions, the SLLBM’s capabilities are demonstrated in various test cases, including a supersonic 2D NACA-0012 airfoil, flow around a 3D sphere, and, to the best of our knowledge, for the first time using an LBM, the 3D simulation of a supersonic turbulent channel flow at a bulk Mach number of <span><math><mrow><mtext>Ma</mtext><mo>=</mo><mn>1.5</mn></mrow></math></span> and a 3D temporal supersonic compressible mixing layer at convective Mach numbers ranging from <span><math><mrow><mtext>Ma</mtext><mo>=</mo><mn>0.3</mn></mrow></math></span> to <span><math><mrow><mtext>Ma</mtext><mo>=</mo><mn>1.2</mn></mrow></math></span>. The results show that the compressible SLLBM is able to adequately capture intrinsic and variable density compressibility effects.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"307 ","pages":"Article 106959"},"PeriodicalIF":3.0,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940526","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}
Pub Date : 2025-12-29DOI: 10.1016/j.compfluid.2025.106956
Quentin Chauleur , Radu Chicireanu , Guillaume Dujardin , Jean-Claude Garreau , Adam Rançon
We consider the Gross-Pitaevskii equation with a confining ring potential with a Gaussian profile. By introducing a rotating sinusoidal perturbation, we numerically highlight the nucleation of quantum vortices in a particular regime throughout the dynamics. Numerical computations are made via a Strang splitting time integration and a two-point flux approximation Finite Volume scheme based on a particular admissible triangulation. We also develop numerical algorithms for vortex tracking adapted to our finite volume framework.
{"title":"Numerical study of the Gross-Pitaevskii equation on a two-dimensional ring and vortex nucleation","authors":"Quentin Chauleur , Radu Chicireanu , Guillaume Dujardin , Jean-Claude Garreau , Adam Rançon","doi":"10.1016/j.compfluid.2025.106956","DOIUrl":"10.1016/j.compfluid.2025.106956","url":null,"abstract":"<div><div>We consider the Gross-Pitaevskii equation with a confining ring potential with a Gaussian profile. By introducing a rotating sinusoidal perturbation, we numerically highlight the nucleation of quantum vortices in a particular regime throughout the dynamics. Numerical computations are made via a Strang splitting time integration and a two-point flux approximation Finite Volume scheme based on a particular admissible triangulation. We also develop numerical algorithms for vortex tracking adapted to our finite volume framework.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"307 ","pages":"Article 106956"},"PeriodicalIF":3.0,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940527","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}
Pub Date : 2025-12-29DOI: 10.1016/j.compfluid.2025.106952
Rémi Abgrall , Alina Chertock , Alexander Kurganov , Lorenzo Micalizzi
In this work, we introduce new second-order schemes for one- and two-dimensional hyperbolic systems of conservation laws. Following an approach recently proposed in [R. Abgrall, Commun. Appl. Math. Comput., 5 (2023), pp. 370–402], we consider two different formulations of the studied system (the original conservative formulation and a primitive one containing nonconservative products), and discretize them on overlapping staggered meshes using two different numerical schemes. The novelty of our approach is twofold. First, we introduce an original paradigm making use of overlapping finite-volume (FV) meshes over which cell averages of conservative and primitive variables are evolved using semi-discrete FV methods: The nonconservative system is discretized by a path-conservative central-upwind scheme, and its solution is used to evaluate very simple numerical fluxes for the discretization of the original conservative system. Second, to ensure the nonlinear stability of the resulting method, we design a post-processing, which also guarantees a conservative coupling between the two sets of variables. We test the proposed semi-discrete dual formulation finite-volume methods on several benchmarks for the Euler equations of gas dynamics.
在这项工作中，我们引入了新的二阶格式的一和二维双曲系统的守恒定律。最近，[R.]Abgrall Commun。达成。数学。第一版。， 5 (2023), pp. 370-402]，我们考虑了所研究系统的两种不同的公式（原始保守公式和包含非保守乘积的原始公式），并使用两种不同的数值格式将它们离散在重叠的交错网格上。我们方法的新颖之处有两个。首先，我们引入了一种利用重叠有限体积（FV）网格的原始范式，其中保守变量和原始变量的单元平均值使用半离散FV方法进行演化：非保守系统通过路径保守中心迎风格式离散，其解用于评估原始保守系统离散化的非常简单的数值通量。其次，为了保证结果方法的非线性稳定性，我们设计了后处理，保证了两组变量之间的保守耦合。我们在几个气体动力学欧拉方程的基准上测试了所提出的半离散对偶公式有限体积方法。
{"title":"Dual formulation finite-volume methods on overlapping meshes for hyperbolic conservation laws","authors":"Rémi Abgrall , Alina Chertock , Alexander Kurganov , Lorenzo Micalizzi","doi":"10.1016/j.compfluid.2025.106952","DOIUrl":"10.1016/j.compfluid.2025.106952","url":null,"abstract":"<div><div>In this work, we introduce new second-order schemes for one- and two-dimensional hyperbolic systems of conservation laws. Following an approach recently proposed in [<span>R. Abgrall</span>, Commun. Appl. Math. Comput., 5 (2023), pp. 370–402], we consider two different formulations of the studied system (the original conservative formulation and a primitive one containing nonconservative products), and discretize them on overlapping staggered meshes using two different numerical schemes. The novelty of our approach is twofold. First, we introduce an original paradigm making use of overlapping finite-volume (FV) meshes over which cell averages of conservative and primitive variables are evolved using semi-discrete FV methods: The nonconservative system is discretized by a path-conservative central-upwind scheme, and its solution is used to evaluate very simple numerical fluxes for the discretization of the original conservative system. Second, to ensure the nonlinear stability of the resulting method, we design a post-processing, which also guarantees a conservative coupling between the two sets of variables. We test the proposed semi-discrete dual formulation finite-volume methods on several benchmarks for the Euler equations of gas dynamics.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"307 ","pages":"Article 106952"},"PeriodicalIF":3.0,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145883381","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}
Pub Date : 2025-12-28DOI: 10.1016/j.compfluid.2025.106955
Anas Jnini , Flavio Vella , Marius Zeinhofer
We propose Gauss-Newton’s method in function space for the solution of the Navier-Stokes equations in the physics-informed neural network (PINN) framework. Upon discretization, this yields a natural gradient method that provably mimics the function space dynamics. Our computational results demonstrate close to single-precision accuracy measured in relative L2 norm on a number of benchmark problems. To the best of our knowledge, this constitutes the first contribution in the PINN literature that solves the Navier-Stokes equations to this degree of accuracy. Finally, we show that given a suitable integral discretization, the proposed optimization algorithm agrees with Gauss-Newton’s method in parameter space. This allows a matrix-free formulation enabling efficient scalability to large network sizes.
{"title":"Gauss-Newton Natural Gradient Descent for Physics-informed Computational Fluid Dynamics","authors":"Anas Jnini , Flavio Vella , Marius Zeinhofer","doi":"10.1016/j.compfluid.2025.106955","DOIUrl":"10.1016/j.compfluid.2025.106955","url":null,"abstract":"<div><div>We propose Gauss-Newton’s method in function space for the solution of the Navier-Stokes equations in the physics-informed neural network (PINN) framework. Upon discretization, this yields a natural gradient method that provably mimics the function space dynamics. Our computational results demonstrate close to single-precision accuracy measured in relative <em>L</em><sup>2</sup> norm on a number of benchmark problems. To the best of our knowledge, this constitutes the first contribution in the PINN literature that solves the Navier-Stokes equations to this degree of accuracy. Finally, we show that given a suitable integral discretization, the proposed optimization algorithm agrees with Gauss-Newton’s method in parameter space. This allows a matrix-free formulation enabling efficient scalability to large network sizes.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"307 ","pages":"Article 106955"},"PeriodicalIF":3.0,"publicationDate":"2025-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940422","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}
Pub Date : 2025-12-27DOI: 10.1016/j.compfluid.2025.106957
Ryuta Takao , Satoshi Ii
Physics-informed neural networks (PINNs) have attracted attention as an alternative approach to solve partial differential equations using a deep neural network (DNN). Their simplicity and capability allow them to solve inverse problems for many applications. Despite the versatility of PINNs, it remains challenging to reduce their training cost. Using a DNN pre-trained with an arbitrary dataset with transfer learning or fine-tuning is a potential solution. However, a pre-trained model using a different geometry and flow condition than the target may not produce suitable results. This paper proposes a fine-tuning approach for PINNs with coordinate transformation, modelling lid-driven cavity flows with various shapes. We formulate the inverse problem, where the reference data inside the domain and wall boundary conditions are given. A pre-trained PINN model with an arbitrary Reynolds number and shape is used to initialize a target DNN. To reconcile the reference shape with different targets, governing equations as a loss of the PINNs are given with coordinate transformation using a deformation gradient tensor. Numerical examples for various cavity flows with square, rectangular, shear deformed and inflated geometries demonstrate that the proposed fine-tuning approach improves the training convergence compared with a randomly-initialized model. A pre-trained model with a similar geometry to the target further increases training efficiency. These findings are useful for real-world applications such as modelling intra-aneurysmal blood flows in clinical use.
{"title":"Fine-tuning physics-informed neural networks for cavity flows using coordinate transformation","authors":"Ryuta Takao , Satoshi Ii","doi":"10.1016/j.compfluid.2025.106957","DOIUrl":"10.1016/j.compfluid.2025.106957","url":null,"abstract":"<div><div>Physics-informed neural networks (PINNs) have attracted attention as an alternative approach to solve partial differential equations using a deep neural network (DNN). Their simplicity and capability allow them to solve inverse problems for many applications. Despite the versatility of PINNs, it remains challenging to reduce their training cost. Using a DNN pre-trained with an arbitrary dataset with transfer learning or fine-tuning is a potential solution. However, a pre-trained model using a different geometry and flow condition than the target may not produce suitable results. This paper proposes a fine-tuning approach for PINNs with coordinate transformation, modelling lid-driven cavity flows with various shapes. We formulate the inverse problem, where the reference data inside the domain and wall boundary conditions are given. A pre-trained PINN model with an arbitrary Reynolds number and shape is used to initialize a target DNN. To reconcile the reference shape with different targets, governing equations as a loss of the PINNs are given with coordinate transformation using a deformation gradient tensor. Numerical examples for various cavity flows with square, rectangular, shear deformed and inflated geometries demonstrate that the proposed fine-tuning approach improves the training convergence compared with a randomly-initialized model. A pre-trained model with a similar geometry to the target further increases training efficiency. These findings are useful for real-world applications such as modelling intra-aneurysmal blood flows in clinical use.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"306 ","pages":"Article 106957"},"PeriodicalIF":3.0,"publicationDate":"2025-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880627","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}
Pub Date : 2025-12-26DOI: 10.1016/j.compfluid.2025.106954
Dingyu Song , Fu Ling , Yonggang Zhang , Binghai Wen
Boundary treatment is an essential issue in the modelling of fluid flows with high accuracy. While the curved boundary conditions can improve the accuracy of simulating complex geometric boundaries in single-phase flows in the lattice Boltzmann method, they usually lead to significant mass leakage and computational errors in multiphase flow. This is primarily because the traditional curved boundary conditions fail to account for nonlinear density variations in the transition region caused by nonideal effects. This study incorporates the nonideal effect into an interpolation scheme and proposes the interpolation-based curved boundary algorithm for multiphase flow, including linear, quadratic, and cubic interpolation schemes. Static and dynamic multiphase simulations with large density ratios demonstrate that this method effectively improves the computational accuracy of multiphase flow boundary conditions. The required mass compensation is negligible, and the spurious velocity is reduced by an order of magnitude compared to conventional methods.
{"title":"Curve boundary algorithms based on interpolation for multiphase lattice Boltzmann method","authors":"Dingyu Song , Fu Ling , Yonggang Zhang , Binghai Wen","doi":"10.1016/j.compfluid.2025.106954","DOIUrl":"10.1016/j.compfluid.2025.106954","url":null,"abstract":"<div><div>Boundary treatment is an essential issue in the modelling of fluid flows with high accuracy. While the curved boundary conditions can improve the accuracy of simulating complex geometric boundaries in single-phase flows in the lattice Boltzmann method, they usually lead to significant mass leakage and computational errors in multiphase flow. This is primarily because the traditional curved boundary conditions fail to account for nonlinear density variations in the transition region caused by nonideal effects. This study incorporates the nonideal effect into an interpolation scheme and proposes the interpolation-based curved boundary algorithm for multiphase flow, including linear, quadratic, and cubic interpolation schemes. Static and dynamic multiphase simulations with large density ratios demonstrate that this method effectively improves the computational accuracy of multiphase flow boundary conditions. The required mass compensation is negligible, and the spurious velocity is reduced by an order of magnitude compared to conventional methods.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"306 ","pages":"Article 106954"},"PeriodicalIF":3.0,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880626","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}
In the context of the numerical approximation of Euler equations, great efforts have been devoted to developing schemes that can accurately reproduce solutions in low Mach number flows. Solutions of classic Finite Volume (FV) schemes are usually plagued by an excessive diffusion as the numerical scheme is not consistent with the limit equations for the Mach number that tends to zero. Instead, a numerical scheme that satisfies such a property is called Asymptotic-Preserving (AP). In this paper, we propose an AP FV scheme for the multi-dimensional Euler equations. In classic FV methods, the numerical approximation of the face flux is obtained by means of a two-state 1D approximate Riemann Solver (RS) in the normal direction to the face. Here, we rely on a node-based flux approximation that exploits a particular RS involving a nodal quantity which depends on all the cells around a given node. Such an idea has been exploited by Barsukow et al. (2023) for the linear acoustic equations. Their method is vorticity-preserving, but its extension to the Euler equations proved to be far from trivial. For such a reason, a change of perspective is needed in the definition of the RS.
{"title":"An all-Mach cell-centered multi-dimensional finite volume numerical scheme for the Euler equations","authors":"Alessia Del Grosso , Wasilij Barsukow , Raphaël Loubère , Pierre-Henri Maire","doi":"10.1016/j.compfluid.2025.106951","DOIUrl":"10.1016/j.compfluid.2025.106951","url":null,"abstract":"<div><div>In the context of the numerical approximation of Euler equations, great efforts have been devoted to developing schemes that can accurately reproduce solutions in low Mach number flows. Solutions of classic Finite Volume (FV) schemes are usually plagued by an excessive diffusion as the numerical scheme is not consistent with the limit equations for the Mach number that tends to zero. Instead, a numerical scheme that satisfies such a property is called Asymptotic-Preserving (AP). In this paper, we propose an AP FV scheme for the multi-dimensional Euler equations. In classic FV methods, the numerical approximation of the face flux is obtained by means of a two-state 1D approximate Riemann Solver (RS) in the normal direction to the face. Here, we rely on a node-based flux approximation that exploits a particular RS involving a nodal quantity which depends on all the cells around a given node. Such an idea has been exploited by Barsukow et al. (2023) for the linear acoustic equations. Their method is vorticity-preserving, but its extension to the Euler equations proved to be far from trivial. For such a reason, a change of perspective is needed in the definition of the RS.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"306 ","pages":"Article 106951"},"PeriodicalIF":3.0,"publicationDate":"2025-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880043","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}
Pub Date : 2025-12-24DOI: 10.1016/j.compfluid.2025.106953
Zihao Zhu, Pau Fradera-Soler, Yalu Zhu, Feng Liu
The flow induced by a pair of Dielectric-Barrier-Discharge (DBD) plasma actuators symmetrically-mounted on a circular cylinder in quiescent air is simulated by solving the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations. A new body-force model for the plasma actuator is developed, which yields significantly improved agreement with experiments. In addition to velocity and vorticity fields, the computations provide time-instantaneous and time-averaged pressure field and pressure and skin friction distributions over the cylinder, which have not been available from existing experiments for this problem. The computational results are analyzed to reveal the relations between the plasma body force, pressure field, velocity, vorticity, forces on the cylinder, and momentum imparted to the flow as they impact the flow control effectiveness for different duty-cycle ratio and frequency of the plasma actuation input. A pair of cumulative vortices is discovered outside the experimental measurement window for the first time by the computations. Regardless of the level of duty-cycle frequency and the detailed near field vortex patterns, the vortices appear to eventually accumulate some distance downstream of the cylinder and move very slowly downstream. The present study is of direct relevance to problems involving vortex shedding and noise production from many circular-shaped aeronautical and civil structures. It helps to provide the necessary fundamental understanding of the flow physics and guidance for future design and optimization of DBD plasma actuators for flow control.
通过求解非定常reynolds - average Navier-Stokes （URANS）方程，模拟了对称安装在圆柱上的一对介质阻挡放电（DBD）等离子体致动器在静止空气中的流动。建立了一种新的等离子体作动器的体力模型，该模型与实验结果吻合较好。除了速度和涡量场之外，计算还提供了时间瞬时和时间平均的压力场以及气缸上的压力和表面摩擦分布，这些都是现有实验无法得到的。通过对计算结果的分析，揭示了在不同占空比和频率下，等离子体体力、压力场、速度、涡量、施加在气缸上的力和传递给流动的动量对流动控制效果的影响关系。通过计算，首次在实验测量窗口外发现了一对累积涡。不管占空比频率的高低和详细的近场涡旋模式如何，涡旋似乎最终会在圆柱体下游积累一定距离，并向下游缓慢移动。本研究直接涉及许多圆形航空和民用结构的涡脱落和噪声产生问题。它有助于为流动物理提供必要的基本理解，并为未来设计和优化用于流动控制的DBD等离子体致动器提供指导。
{"title":"Numerical investigation of flow induced by plasma actuators around a circular cylinder in quiescent air under duty-cycle actuation","authors":"Zihao Zhu, Pau Fradera-Soler, Yalu Zhu, Feng Liu","doi":"10.1016/j.compfluid.2025.106953","DOIUrl":"10.1016/j.compfluid.2025.106953","url":null,"abstract":"<div><div>The flow induced by a pair of Dielectric-Barrier-Discharge (DBD) plasma actuators symmetrically-mounted on a circular cylinder in quiescent air is simulated by solving the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations. A new body-force model for the plasma actuator is developed, which yields significantly improved agreement with experiments. In addition to velocity and vorticity fields, the computations provide time-instantaneous and time-averaged pressure field and pressure and skin friction distributions over the cylinder, which have not been available from existing experiments for this problem. The computational results are analyzed to reveal the relations between the plasma body force, pressure field, velocity, vorticity, forces on the cylinder, and momentum imparted to the flow as they impact the flow control effectiveness for different duty-cycle ratio and frequency of the plasma actuation input. A pair of cumulative vortices is discovered outside the experimental measurement window for the first time by the computations. Regardless of the level of duty-cycle frequency and the detailed near field vortex patterns, the vortices appear to eventually accumulate some distance downstream of the cylinder and move very slowly downstream. The present study is of direct relevance to problems involving vortex shedding and noise production from many circular-shaped aeronautical and civil structures. It helps to provide the necessary fundamental understanding of the flow physics and guidance for future design and optimization of DBD plasma actuators for flow control.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"306 ","pages":"Article 106953"},"PeriodicalIF":3.0,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880628","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}
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