Pub Date : 2026-03-15Epub 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":"2026-03-15","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 : 2026-03-15Epub Date: 2026-01-19DOI: 10.1016/j.compfluid.2026.106978
G. de Romémont , F. Renac , J. Nunez , D. Gueyffier , F. Chinesta
This paper presents a data-driven finite volume method for solving 1D and 2D hyperbolic partial differential equations. This work builds upon prior research [5, 27, 75] incorporating a data-driven finite-difference approximation of smooth solutions of scalar conservation laws, where optimal coefficients of neural networks approximating space derivatives are learned based on accurate, but cumbersome solutions to these equations. We extend this approach to MUSCL-type finite volume approximations of hyperbolic scalar and systems of conservation laws. We also train the discretization to efficiently capture discontinuous solutions with shock and contact waves, as well as to the application of boundary conditions. The learning procedure of the data-driven model is extended through the definition of a new loss with added regularizers, paddings and adequate training databases. These new ingredients guarantee computational stability, preserve the accuracy of fine-grid solutions, and enhance overall performance. Numerical experiments using test cases from the literature in both one and two-dimensional spaces demonstrate that the learned model accurately reproduces fine-grid results on very coarse meshes achieving 20–50% gains in accuracy.
{"title":"A data-driven learned discretization approach in finite volume schemes for hyperbolic conservation laws and varying boundary conditions","authors":"G. de Romémont , F. Renac , J. Nunez , D. Gueyffier , F. Chinesta","doi":"10.1016/j.compfluid.2026.106978","DOIUrl":"10.1016/j.compfluid.2026.106978","url":null,"abstract":"<div><div>This paper presents a data-driven finite volume method for solving 1D and 2D hyperbolic partial differential equations. This work builds upon prior research [5, 27, 75] incorporating a data-driven finite-difference approximation of smooth solutions of scalar conservation laws, where optimal coefficients of neural networks approximating space derivatives are learned based on accurate, but cumbersome solutions to these equations. We extend this approach to MUSCL-type finite volume approximations of hyperbolic scalar and systems of conservation laws. We also train the discretization to efficiently capture discontinuous solutions with shock and contact waves, as well as to the application of boundary conditions. The learning procedure of the data-driven model is extended through the definition of a new loss with added regularizers, paddings and adequate training databases. These new ingredients guarantee computational stability, preserve the accuracy of fine-grid solutions, and enhance overall performance. Numerical experiments using test cases from the literature in both one and two-dimensional spaces demonstrate that the learned model accurately reproduces fine-grid results on very coarse meshes achieving 20–50% gains in accuracy.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"307 ","pages":"Article 106978"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146034934","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 : 2026-03-15Epub Date: 2026-01-17DOI: 10.1016/j.compfluid.2026.106977
Jingchao Zhang , Yue Zhang , Song Chen , Guanxin Hong
Numerical simulations of chemically reacting flows often suffer from stiffness arising from the large disparities in time scales among advection, diffusion, and chemical reactions, which severely limits computational efficiency. To address this challenge, this study proposes a hybrid implicit-explicit component-splitting method that decomposes the governing equations into two subsystems: a flow subsystem handling advection-viscous terms through explicit time integration, and a component subsystem treating diffusion-reaction terms via implicit time integration. This framework effectively combines the accuracy of explicit methods with the efficiency and stability of implicit schemes. In regions exhibiting strong stiffness, the local time step of the component subsystem is adaptively reduced by an appropriately chosen divisor to improve numerical stability and robustness. Furthermore, a species-invariance criterion based on local mass-fraction gradients and reaction activity is incorporated to selectively update the component subsystem, thereby reducing redundant computations. For unsteady flows, the proposed method permits significantly larger time steps than explicit Runge-Kutta schemes, while for steady flows it increases the maximum stable Courant-Friedrichs-Lewy number and reduces time cost per iteration. Several test cases, including hydrogen-air detonations and hypersonic non-equilibrium flows, demonstrate the method’s effectiveness: it maintains stability at large time steps, accurately captures the complex interactions between shock and detonation waves, and shows excellent agreement with high-order Runge-Kutta simulations. Overall, the proposed implicit-explicit method enables efficient, accurate, and robust simulations of chemically reacting flows with stiff chemistry.
{"title":"A hybrid implicit-explicit time integration for stiff chemically reacting flows based on adaptive component-splitting method","authors":"Jingchao Zhang , Yue Zhang , Song Chen , Guanxin Hong","doi":"10.1016/j.compfluid.2026.106977","DOIUrl":"10.1016/j.compfluid.2026.106977","url":null,"abstract":"<div><div>Numerical simulations of chemically reacting flows often suffer from stiffness arising from the large disparities in time scales among advection, diffusion, and chemical reactions, which severely limits computational efficiency. To address this challenge, this study proposes a hybrid implicit-explicit component-splitting method that decomposes the governing equations into two subsystems: a flow subsystem handling advection-viscous terms through explicit time integration, and a component subsystem treating diffusion-reaction terms via implicit time integration. This framework effectively combines the accuracy of explicit methods with the efficiency and stability of implicit schemes. In regions exhibiting strong stiffness, the local time step of the component subsystem is adaptively reduced by an appropriately chosen divisor to improve numerical stability and robustness. Furthermore, a species-invariance criterion based on local mass-fraction gradients and reaction activity is incorporated to selectively update the component subsystem, thereby reducing redundant computations. For unsteady flows, the proposed method permits significantly larger time steps than explicit Runge-Kutta schemes, while for steady flows it increases the maximum stable Courant-Friedrichs-Lewy number and reduces time cost per iteration. Several test cases, including hydrogen-air detonations and hypersonic non-equilibrium flows, demonstrate the method’s effectiveness: it maintains stability at large time steps, accurately captures the complex interactions between shock and detonation waves, and shows excellent agreement with high-order Runge-Kutta simulations. Overall, the proposed implicit-explicit method enables efficient, accurate, and robust simulations of chemically reacting flows with stiff chemistry.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"307 ","pages":"Article 106977"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146034933","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 : 2026-03-15Epub 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":"2026-03-15","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 : 2026-03-15Epub 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":"2026-03-15","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 : 2026-03-15Epub Date: 2025-11-04DOI: 10.1016/j.compfluid.2025.106886
Wasilij Barsukow , Praveen Chandrashekar , Christian Klingenberg , Lisa Lechner
The Active Flux method can be seen as an extended finite volume method. The degrees of freedom of this method are cell averages, as in finite volume methods, and in addition shared point values at the cell interfaces, giving rise to a globally continuous reconstruction. Its classical version was introduced as a one-stage fully discrete, third-order method. Recently, a semi-discrete version of the Active Flux method was presented with various extensions to arbitrarily high order in one space dimension. In this paper we extend the semi-discrete Active Flux method on two-dimensional Cartesian grids to arbitrarily high order, by including moments as additional degrees of freedom (hybrid finite element–finite volume method). The stability of this method is studied for linear advection. For a fully discrete version, using an explicit Runge-Kutta method, a CFL restriction is derived. We end by presenting numerical examples for hyperbolic conservation laws.
{"title":"A generalized Active Flux method of arbitrarily high order in two dimensions","authors":"Wasilij Barsukow , Praveen Chandrashekar , Christian Klingenberg , Lisa Lechner","doi":"10.1016/j.compfluid.2025.106886","DOIUrl":"10.1016/j.compfluid.2025.106886","url":null,"abstract":"<div><div>The Active Flux method can be seen as an extended finite volume method. The degrees of freedom of this method are cell averages, as in finite volume methods, and in addition shared point values at the cell interfaces, giving rise to a globally continuous reconstruction. Its classical version was introduced as a one-stage fully discrete, third-order method. Recently, a semi-discrete version of the Active Flux method was presented with various extensions to arbitrarily high order in <em>one</em> space dimension. In this paper we extend the semi-discrete Active Flux method on <em>two</em>-dimensional Cartesian grids to arbitrarily high order, by including moments as additional degrees of freedom (hybrid finite element–finite volume method). The stability of this method is studied for linear advection. For a fully discrete version, using an explicit Runge-Kutta method, a CFL restriction is derived. We end by presenting numerical examples for hyperbolic conservation laws.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"307 ","pages":"Article 106886"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940421","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 : 2026-03-15Epub Date: 2026-01-14DOI: 10.1016/j.compfluid.2026.106973
Antonio Blanco-Casares, Daniel Mira, Oriol Lehmkuhl
This work presents a low-dissipative numerical method to solve the scalar transport equation with an exhaustive analysis of its application to reacting flows in the limit of perfectly premixed combustion with a low-Mach number formulation. A tabulated flamelet model is used to simplify the chemical reactions. The proposed method is presented for a generic conservation law and its property-preserving capability is proved on linear advection tests, in which it proves the preservation of strong gradients and the ability of controlling overshoots-undershoots. Even though the TVD property is not guaranteed, the numerical oscillations are greatly reduced. Then, the method is adapted to solve the convection-diffusion transport scalar equation with source terms, which is the core of any reacting flow simulation. The implementation is validated with the one-dimensional flame problem and then is tested in a turbulent combustion case. The comparison between the results obtained with conventional methods based on high-dissipation and the proposed low-dissipative approach shows clear benefits of the later, the interfaces are sharper and there is an improvement in the representation of the flame front. This formulation also shows capability to capture much more flow structures which make the simulation a closer representation of the actual physics.
{"title":"A low-dissipation continuous Galerkin formulation for turbulent premixed combustion","authors":"Antonio Blanco-Casares, Daniel Mira, Oriol Lehmkuhl","doi":"10.1016/j.compfluid.2026.106973","DOIUrl":"10.1016/j.compfluid.2026.106973","url":null,"abstract":"<div><div>This work presents a low-dissipative numerical method to solve the scalar transport equation with an exhaustive analysis of its application to reacting flows in the limit of perfectly premixed combustion with a low-Mach number formulation. A tabulated flamelet model is used to simplify the chemical reactions. The proposed method is presented for a generic conservation law and its property-preserving capability is proved on linear advection tests, in which it proves the preservation of strong gradients and the ability of controlling overshoots-undershoots. Even though the TVD property is not guaranteed, the numerical oscillations are greatly reduced. Then, the method is adapted to solve the convection-diffusion transport scalar equation with source terms, which is the core of any reacting flow simulation. The implementation is validated with the one-dimensional flame problem and then is tested in a turbulent combustion case. The comparison between the results obtained with conventional methods based on high-dissipation and the proposed low-dissipative approach shows clear benefits of the later, the interfaces are sharper and there is an improvement in the representation of the flame front. This formulation also shows capability to capture much more flow structures which make the simulation a closer representation of the actual physics.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"307 ","pages":"Article 106973"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974158","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 : 2026-03-15Epub Date: 2026-01-14DOI: 10.1016/j.compfluid.2026.106972
Mustafa Ishak Benzaza , David Uystepruyst , François Beaubert , Damien Méresse , François Delcourt , Céline Morin
This work investigates both experimentally and numerically the turbulent flow within cyclonic separators using DES and VLES turbulence methods. Numerical predictions are validated against Hoekstra’s experimental data, showing that DES accurately captures the tangential velocity and pressure drop, but struggles to reproduce the axial velocity, particularly near the vortex core. Several outlet boundary conditions, including the addition of an obstacle, are tested to improve flow representation. A mapped pressure boundary condition offers a more physically consistent solution. Furthermore, spectral analysis is used to identify the end of the unsteady transient regime and the dominant flow frequencies. The effect of cyclone body height is also investigated both experimentally and numerically by comparing two industrial configurations. Shorter cyclone bodies lead to lower velocities and higher swirl numbers at the cyclone body and near the outlet, while taller cyclones significantly mitigate the Precessing Vortex Core effect and reduce vortex intensity at the outlet region.
{"title":"Modeling and analysis of swirling flow in cyclone separators using various hybrid scale-resolving approaches","authors":"Mustafa Ishak Benzaza , David Uystepruyst , François Beaubert , Damien Méresse , François Delcourt , Céline Morin","doi":"10.1016/j.compfluid.2026.106972","DOIUrl":"10.1016/j.compfluid.2026.106972","url":null,"abstract":"<div><div>This work investigates both experimentally and numerically the turbulent flow within cyclonic separators using DES and VLES turbulence methods. Numerical predictions are validated against Hoekstra’s experimental data, showing that DES accurately captures the tangential velocity and pressure drop, but struggles to reproduce the axial velocity, particularly near the vortex core. Several outlet boundary conditions, including the addition of an obstacle, are tested to improve flow representation. A mapped pressure boundary condition offers a more physically consistent solution. Furthermore, spectral analysis is used to identify the end of the unsteady transient regime and the dominant flow frequencies. The effect of cyclone body height is also investigated both experimentally and numerically by comparing two industrial configurations. Shorter cyclone bodies lead to lower velocities and higher swirl numbers at the cyclone body and near the outlet, while taller cyclones significantly mitigate the Precessing Vortex Core effect and reduce vortex intensity at the outlet region.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"307 ","pages":"Article 106972"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146034932","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 : 2026-03-15Epub Date: 2026-01-10DOI: 10.1016/j.compfluid.2026.106969
Matteo Savino, Alessia Ferrari, Renato Vacondio, Paolo Mignosa
In this work, we introduce a novel fully implicit numerical scheme for the two-dimensional Vertically Averaged and Moment (VAM) system of equations. The method combines a Discontinuous Galerkin (DG) discretization of the homogeneous system with a local Taylor-based reconstruction of the non-conservative terms, ensuring stability without the need for empirical tuning parameters. The full set of equations is advanced in time, following a third-order accurate linear implicit Runge-Kutte (LIRK) method, through a single implicit step, where the fluxes and source terms are linearized via a Taylor-series expansion, thus avoiding computationally expensive iterative solvers. The effectiveness of the approach is demonstrated against experimental benchmarks, showing excellent agreement in both steady and unsteady flow regimes. Notably, the scheme remains robust for Courant-Friedrichs-Lewy (CFL) numbers up to 10, underscoring its potential for efficient large-scale simulations. Most importantly, the proposed formulation enables the simulation of non-hydrostatic pressure flows within a two-dimensional grid, thereby capturing essential three-dimensional effects without the prohibitive cost of fully 3D solvers.
{"title":"A fully implicit Discontinuous Galerkin finite element scheme for the 2D vertically averaged and moment equations","authors":"Matteo Savino, Alessia Ferrari, Renato Vacondio, Paolo Mignosa","doi":"10.1016/j.compfluid.2026.106969","DOIUrl":"10.1016/j.compfluid.2026.106969","url":null,"abstract":"<div><div>In this work, we introduce a novel fully implicit numerical scheme for the two-dimensional Vertically Averaged and Moment (VAM) system of equations. The method combines a Discontinuous Galerkin (DG) discretization of the homogeneous system with a local Taylor-based reconstruction of the non-conservative terms, ensuring stability without the need for empirical tuning parameters. The full set of equations is advanced in time, following a third-order accurate linear implicit Runge-Kutte (LIRK) method, through a single implicit step, where the fluxes and source terms are linearized via a Taylor-series expansion, thus avoiding computationally expensive iterative solvers. The effectiveness of the approach is demonstrated against experimental benchmarks, showing excellent agreement in both steady and unsteady flow regimes. Notably, the scheme remains robust for Courant-Friedrichs-Lewy (CFL) numbers up to 10, underscoring its potential for efficient large-scale simulations. Most importantly, the proposed formulation enables the simulation of non-hydrostatic pressure flows within a two-dimensional grid, thereby capturing essential three-dimensional effects without the prohibitive cost of fully 3D solvers.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"307 ","pages":"Article 106969"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974155","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 : 2026-03-15Epub 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":"2026-03-15","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}
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