Computers & Fluids最新文献_第2页

On the applicability of the EDAC method to non-Oberbeck–Boussinesq regimes in buoyancy-driven flows 关于EDAC方法在浮力驱动流中非oberbeck - boussinesq格式中的适用性

IF 3 3区工程技术

Computers & Fluids Pub Date : 2025-09-22 DOI: 10.1016/j.compfluid.2025.106835

Kasturi Srikanth , V. Praveen Kumar , T. Jayachandran , A. Sameen , Manjul Sharma

{"title":"On the applicability of the EDAC method to non-Oberbeck–Boussinesq regimes in buoyancy-driven flows","authors":"Kasturi Srikanth , V. Praveen Kumar , T. Jayachandran , A. Sameen , Manjul Sharma","doi":"10.1016/j.compfluid.2025.106835","DOIUrl":"10.1016/j.compfluid.2025.106835","url":null,"abstract":"<div><div>This work presents an extension of the Entropically Damped Artificial Compressibility (EDAC) method to simulate buoyancy-driven flows under Non-Oberbeck–Boussinesq (NOB) conditions, characterized by strong thermophysical property variations. By integrating realistic data from the National Institute of Standards and Technology (NIST) database, the formulation accounts for temperature-dependent density and transport coefficients. A sixth-order compact finite-difference scheme with high-order filtering and Runge–Kutta time integration is used to solve the equations in a Rayleigh–Benard convection configuration for air, water, and steam. Diagnostic quantities such as the central temperature shift, relative Nusselt number, and RMS velocity divergence confirm agreement with existing literature. Despite not enforcing incompressibility explicitly, the method exhibits low divergence errors, even in high density gradient cases like steam. These results demonstrate the accuracy and robustness of EDAC for NOB flows, offering a viable alternative to traditional pressure Poisson solvers.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"302 ","pages":"Article 106835"},"PeriodicalIF":3.0,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155928","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}

引用次数: 0

Disentangled latent spaces for reduced order models using deterministic autoencoders 使用确定性自编码器的降阶模型的解纠缠潜在空间

IF 3 3区工程技术

Computers & Fluids Pub Date : 2025-09-19 DOI: 10.1016/j.compfluid.2025.106837

Henning Schwarz , Pyei Phyo Lin , Jens-Peter M. Zemke , Thomas Rung

{"title":"Disentangled latent spaces for reduced order models using deterministic autoencoders","authors":"Henning Schwarz , Pyei Phyo Lin , Jens-Peter M. Zemke , Thomas Rung","doi":"10.1016/j.compfluid.2025.106837","DOIUrl":"10.1016/j.compfluid.2025.106837","url":null,"abstract":"<div><div>Data-driven reduced-order models based on autoencoders generally lack interpretability compared to classical methods such as the proper orthogonal decomposition. More interpretability can be gained by disentangling the latent variables and analyzing the resulting modes. For this purpose, probabilistic <span><math><mi>β</mi></math></span>-variational autoencoders (<span><math><mi>β</mi></math></span>-VAEs) are frequently used in computational fluid dynamics and other simulation sciences. Using a benchmark periodic flow dataset, we show that competitive results can be achieved using non-probabilistic autoencoder approaches that either promote orthogonality or penalize correlation between latent variables. Compared to probabilistic autoencoders, these approaches offer more robustness with respect to the choice of hyperparameters entering the loss function. We further demonstrate the ability of a non-probabilistic approach to identify a reduced number of active latent variables by introducing a correlation penalty, a function also known from the use of <span><math><mi>β</mi></math></span>-VAE. The investigated probabilistic and non-probabilistic autoencoder models are finally used for the dimensionality reduction of aircraft ditching loads, which serves as an industrial application in this work.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"302 ","pages":"Article 106837"},"PeriodicalIF":3.0,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119328","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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Immersed boundaries in the discontinuous Galerkin spectral element method through hp-adaptivity 基于hp自适应的不连续伽辽金谱元方法中浸入边界

IF 3 3区工程技术

Computers & Fluids Pub Date : 2025-09-19 DOI: 10.1016/j.compfluid.2025.106840

Amit Nayak, Catherine Mavriplis

引用次数: 0

An efficient computational method for studying the interaction of strong turbulence with a free-surface 研究强湍流与自由表面相互作用的有效计算方法

IF 3 3区工程技术

Computers & Fluids Pub Date : 2025-09-19 DOI: 10.1016/j.compfluid.2025.106836

Andre Calado, Ibrahim Yildiran, Elias Balaras

{"title":"An efficient computational method for studying the interaction of strong turbulence with a free-surface","authors":"Andre Calado, Ibrahim Yildiran, Elias Balaras","doi":"10.1016/j.compfluid.2025.106836","DOIUrl":"10.1016/j.compfluid.2025.106836","url":null,"abstract":"<div><div>Strong turbulence interacting with a free-surface is a challenging problem, where the interface between gas and liquid is disrupted, generating droplets and bubbles. Turbulent bubble entrainment and breakdown is of paramount importance to quantify mass and momentum transport, and developing lower order models. Thus far, computational costs of scale resolving simulations (for both interface and turbulence) have limited the ability to study these flows. In this work we leverage recent advances in two-phase solvers, including a splitting scheme for the Poisson equation allowing the use of FFT-based Fast Poisson Solvers (FPS) greatly reducing solution time, with verifiable accuracy; coupled with the Ghost Fluid Method (GFM) for a sharp interface treatment. The proposed formulation uses the level set approach, with a dual-redistancing scheme for global mass conservation of each phase. To analyze strong free-surface turbulence, homogeneous isotropic turbulence (HIT) is forced under an air–water interface to analyze stationary statistics of the flow including entrained bubble sizes and Reynolds stresses. Two different approaches are used for the sub-surface forcing. The first uses the common linear forcing scheme in physical space, which imposes a constraint on the domain size. The alternative approach relies on the synthetic random Fourier method to generate a boundary condition which reduces the total computational domain, allowing for higher Reynolds number simulations of turbulent free-surface flows.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"302 ","pages":"Article 106836"},"PeriodicalIF":3.0,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107208","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}

引用次数: 0

Sparse Identification for bifurcating phenomena in Computational Fluid Dynamics 计算流体力学中分岔现象的稀疏识别

IF 3 3区工程技术

Computers & Fluids Pub Date : 2025-09-19 DOI: 10.1016/j.compfluid.2025.106841

Lorenzo Tomada, Moaad Khamlich, Federico Pichi, Gianluigi Rozza

{"title":"Sparse Identification for bifurcating phenomena in Computational Fluid Dynamics","authors":"Lorenzo Tomada, Moaad Khamlich, Federico Pichi, Gianluigi Rozza","doi":"10.1016/j.compfluid.2025.106841","DOIUrl":"10.1016/j.compfluid.2025.106841","url":null,"abstract":"<div><div>This work investigates model reduction techniques for nonlinear parameterized and time-dependent PDEs, specifically focusing on bifurcating phenomena in Computational Fluid Dynamics (CFD). We develop interpretable and non-intrusive Reduced Order Models (ROMs) capable of capturing dynamics associated with bifurcations by identifying a minimal set of coordinates.</div><div>Our methodology combines the Sparse Identification of Nonlinear Dynamics (SINDy) method with a deep learning framework based on Autoencoder (AE) architectures. To enhance dimensionality reduction, we integrate a nested Proper Orthogonal Decomposition (POD) with the SINDy-AE architecture, enabling a sparse discovery of system dynamics while maintaining efficiency of the reduced model.</div><div>We demonstrate our approach via two challenging test cases defined on sudden-expansion channel geometries: a symmetry-breaking bifurcation and a Hopf bifurcation. Starting from a comprehensive analysis of their high-fidelity behavior, i.e. symmetry-breaking phenomena and the rise of unsteady periodic solutions, we validate the accuracy and computational efficiency of our ROMs.</div><div>The results show successful reconstruction of the bifurcations, accurate prediction of system evolution for unseen parameter values, and significant speed-up compared to full-order methods.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"302 ","pages":"Article 106841"},"PeriodicalIF":3.0,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119327","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}

引用次数: 0

ONERA’s CRM WBPN database for machine learning activities, related regression challenge and first results ONERA的CRM WBPN数据库，用于机器学习活动、相关回归挑战和首次结果

IF 3 3区工程技术

Computers & Fluids Pub Date : 2025-09-19 DOI: 10.1016/j.compfluid.2025.106838

Jacques Peter , Quentin Bennehard , Sébastien Heib , Jean-Luc Hantrais-Gervois , Frédéric Moëns

{"title":"ONERA’s CRM WBPN database for machine learning activities, related regression challenge and first results","authors":"Jacques Peter , Quentin Bennehard , Sébastien Heib , Jean-Luc Hantrais-Gervois , Frédéric Moëns","doi":"10.1016/j.compfluid.2025.106838","DOIUrl":"10.1016/j.compfluid.2025.106838","url":null,"abstract":"<div><div>This paper presents a new Computational Fluid Dynamics database, developed at ONERA, to support the advancement of machine learning techniques for aerodynamic field prediction. It contains 468 Reynolds-Averaged Navier–Stokes simulations using the Spalart–Allmaras turbulence model, performed on the NASA/Boeing Common Research Model wing-body-pylon-nacelle configuration. The database spans a wide range of flow conditions, varying Mach number (including transonic regimes), angle of attack (capturing flow separation), and Reynolds number (based on three stagnation pressures, with one setting matching wind tunnel experiments). The numerical quality of the database is assessed, through checking the convergence level of each computation.</div><div>Based on these data, a regression challenge is defined. It consists in predicting the wall distributions of pressure and friction coefficients for unseen aerodynamic conditions. The 468 simulations are split into training and test sets, with the training data made available publicly on the Codabench platform. The paper further evaluates several classical machine learning regressors on this task. Tested pointwise methods include Multilayer Perceptrons, <span><math><mi>λ</mi></math></span>-DNNs, and Decision Trees, while global methods include Multilayer Perceptron, k-Nearest Neighbors, Proper Orthogonal Decomposition and IsoMap. Initial performance results, using <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> scores and largest relative mean absolute error metrics, are presented, offering insights into the capabilities of these techniques for the challenge and references for future work.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"302 ","pages":"Article 106838"},"PeriodicalIF":3.0,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155927","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}

引用次数: 0

Versatile mixed methods for weakly-compressible flows 弱可压缩流的通用混合方法

IF 3 3区工程技术

Computers & Fluids Pub Date : 2025-09-18 DOI: 10.1016/j.compfluid.2025.106833

Edward A. Miller, David M. Williams

{"title":"Versatile mixed methods for weakly-compressible flows","authors":"Edward A. Miller, David M. Williams","doi":"10.1016/j.compfluid.2025.106833","DOIUrl":"10.1016/j.compfluid.2025.106833","url":null,"abstract":"<div><div>Versatile mixed finite element methods were originally developed by Chen and Williams for isothermal incompressible flows in “Versatile mixed methods for the incompressible Navier–Stokes equations,” Computers & Mathematics with Applications, Volume 80, 2020. Thereafter, these methods were extended by Miller, Chen, and Williams to non-isothermal incompressible flows in “Versatile mixed methods for non-isothermal incompressible flows,” Computers & Mathematics with Applications, Volume 125, 2022. The main advantage of these methods lies in their flexibility. Unlike traditional mixed methods, they retain the divergence terms in the momentum and temperature equations. As a result, the favorable properties of the schemes are maintained even in the presence of non-zero divergence. This makes them an ideal candidate for an extension to compressible flows, in which the divergence does not generally vanish. In the present article, we finally construct the compressible extension of the methods. In addition, we demonstrate the excellent performance of the resulting methods for weakly-compressible flows that arise near the incompressible limit, as well as moderately-compressible flows that arise near Mach 0.5.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"302 ","pages":"Article 106833"},"PeriodicalIF":3.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217509","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}

引用次数: 0

A stable and accurate finite difference approximation for the incompressible lid-driven cavity flow with focus on the corner singularities 不可压盖驱动腔体流动的稳定精确有限差分近似，重点关注拐角奇点

IF 3 3区工程技术

Computers & Fluids Pub Date : 2025-09-17 DOI: 10.1016/j.compfluid.2025.106826

Prince Nchupang , Arnaud G. Malan , Jan Nordström

{"title":"A stable and accurate finite difference approximation for the incompressible lid-driven cavity flow with focus on the corner singularities","authors":"Prince Nchupang , Arnaud G. Malan , Jan Nordström","doi":"10.1016/j.compfluid.2025.106826","DOIUrl":"10.1016/j.compfluid.2025.106826","url":null,"abstract":"<div><div>The lid-driven cavity test case is widely used to validate incompressible Navier–Stokes flow solvers. However, the rigorous treatment of discontinuous corner boundary conditions remains a challenge for high-order methods. This is the main goal of the paper. We write the incompressible Navier–Stokes equations in skew-symmetric form and we impose the boundary conditions weakly which leads to boundedness without any special treatment in the corners. The continuous procedure is mimicked in the discrete setting using high-order finite difference methods in Summation-By-Parts (SBP) form complemented with weak boundary conditions using the Simultaneous Approximation Term (SAT) technique. Stability is then formally proven using the SBP-SAT framework. Numerical tests commence with a method-of-manufactured solution and the scheme is shown to be high order accurate. The lid-driven cavity test case is finally studied using a 4th order accurate scheme and the results are compared to benchmark solutions. Accurate solutions are achieved that are devoid of spurious oscillations near the top corners and the velocities remain bounded, demonstrating the unique versatility of the weak SAT boundary treatment.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"302 ","pages":"Article 106826"},"PeriodicalIF":3.0,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107144","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}

引用次数: 0

An adaptive fifth-degree kernel for suppressing stress instability in SPH for compressible flows 一种抑制可压缩流SPH应力不稳定性的自适应五度核

IF 3 3区工程技术

Computers & Fluids Pub Date : 2025-09-17 DOI: 10.1016/j.compfluid.2025.106844

Wenbo Fan , Jun Liu , Delong Xiao

{"title":"An adaptive fifth-degree kernel for suppressing stress instability in SPH for compressible flows","authors":"Wenbo Fan , Jun Liu , Delong Xiao","doi":"10.1016/j.compfluid.2025.106844","DOIUrl":"10.1016/j.compfluid.2025.106844","url":null,"abstract":"<div><div>The phenomenon of stress instability is frequently observed in smooth particle hydrodynamics (SPH), which manifests as unphysical clustering or separation of particles, and constrains the application of SPH. In this paper, we propose an adaptive fifth-degree kernel function for alleviating stress instability in compressible flows. The shape of kernel function can be adaptively modified according to the particle states, circumventing the conditions associated with instability and thus alleviating both compressive and tensile instability. For the case where two particles in a particle pair use different kernels, discrete formulations of the momentum and thermal equations within the Conservative Reproducing Kernel Smoothed Particle Hydrodynamics (CRKSPH) framework are employed to ensure the conservation. Several benchmark cases of compressible flows are simulated utilizing the adaptive fifth-degree kernel, and results indicate that the adaptive fifth-degree kernel can sustain homogeneous particle distributions and clear shock wave fronts after multiple bounces of shock and rarefaction waves, effectively alleviating the stress instability inherent in classical SPH methods. In addition, the adaptive fifth-degree kernel can ensure reasonable spacing of particle pairs even when negative pressure is encountered, and avoid particle clustering or voids in the computational domain.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"302 ","pages":"Article 106844"},"PeriodicalIF":3.0,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107143","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}

引用次数: 0

Effect of spanwise load distribution on aerodynamic performance of compressor cascade based on inverse design method 基于反设计方法的压气机叶栅展向负荷分布对气动性能的影响

IF 3 3区工程技术

Computers & Fluids Pub Date : 2025-09-15 DOI: 10.1016/j.compfluid.2025.106842

Yutian Chen, Qun Zheng, Yuting Jiang

{"title":"Effect of spanwise load distribution on aerodynamic performance of compressor cascade based on inverse design method","authors":"Yutian Chen, Qun Zheng, Yuting Jiang","doi":"10.1016/j.compfluid.2025.106842","DOIUrl":"10.1016/j.compfluid.2025.106842","url":null,"abstract":"<div><div>The impact of cascade spanwise load distribution on aerodynamic loss and flow field structure is investigated. A novel inverse design method is developed based on the correlation between streamline slope and static pressure coefficient. The proposed method drives blade profile modifications to minimize discrepancies between target and actual load distributions. Using an experimentally validated cascade, the inverse design method is employed to adjust load distributions from 10 % to 50 % spanwise locations, resulting in five cascades with varying spanwise load distributions. Verification studies confirm the reliability of the inverse design method. Numerical simulations demonstrate that excessive spanwise static pressure gradients expand the corner separation region through enhanced crossflow transition, thereby reducing passage flow capacity and increasing aerodynamic losses. However, appropriate spanwise load distributions effectively control the total pressure loss coefficient across various attack angles. An optimized cascade yields a 10.4 % reduction in the total pressure loss coefficient at 0° attack angle compared to the initial cascade.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"302 ","pages":"Article 106842"},"PeriodicalIF":3.0,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107209","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}

引用次数: 0