Computers & Fluids最新文献

{"title":"Predictive dynamic wetting, fluid–structure interaction simulations for braze run-out","authors":"Jeffrey S. Horner ,&nbsp;David J. Kemmenoe ,&nbsp;Gustav J. Bourdon ,&nbsp;Scott A. Roberts ,&nbsp;Edward R. Arata ,&nbsp;Jaideep Ray ,&nbsp;Anne M. Grillet","doi":"10.1016/j.compfluid.2025.106567","DOIUrl":"10.1016/j.compfluid.2025.106567","url":null,"abstract":"<div><div>Brazing and soldering are metallurgical joining techniques that use a wetting molten metal to create a joint between two faying surfaces. The quality of the brazing process depends strongly on the wetting properties of the molten filler metal, namely the surface tension and contact angle, and the resulting joint can be susceptible to various defects, such as run-out and underfill, if the material properties or joining conditions are not suitable. In this work, we implement a finite element simulation to predict the formation of such defects in braze processes. This model incorporates both fluid–structure interaction through an arbitrary Eulerian–Lagrangian technique and free surface wetting through conformal decomposition finite element modeling. Upon validating our numerical simulations against experimental run-out studies on a silver-Kovar system, we then use the model to predict run-out and underfill in systems with variable surface tension, contact angles, and applied pressure. Finally, we consider variable joint/surface geometries and show how different geometrical configurations can help to mitigate run-out. This work aims to understand how brazing defects arise and validate a coupled wetting and fluid–structure interaction simulation that can be used for other industrial problems.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"290 ","pages":"Article 106567"},"PeriodicalIF":2.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386527","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":"Kinetic and macroscopic modelling for dense gas flow simulations","authors":"K.S. Shrinath ,&nbsp;Ramesh Kolluru ,&nbsp;S.V. Raghurama Rao ,&nbsp;Vasudeva Rao Veeredhi ,&nbsp;Sekhar G.N.","doi":"10.1016/j.compfluid.2024.106539","DOIUrl":"10.1016/j.compfluid.2024.106539","url":null,"abstract":"<div><div>This study delves into the complexities of modelling dense gases near thermodynamic critical points, where conventional gas dynamic assumptions prove inadequate. Within this unique regime, non-linear waves exhibit behaviours divergent from classical phenomena, like expansion shocks which remain consistent with entropy conditions. Accurately capturing these phenomena mandates sophisticated equation of state (EoS) that surpasses the ideal gas assumptions, presenting challenges for numerical simulations. In this paper, we propose a simple modification to the Boltzmann equation (with the BGK framework), which, upon taking moments, leads to Euler equations for dense gas flows. We consider van der Waals EoS. Further, we develop a three-velocity model based <em>Kinetic Flux Difference Splitting</em> (KFDS) scheme for the Euler system, with adaptable diffusion coefficients suitable to capture compressible flow phenomena specific to ideal and dense gases. This innovative approach diverges from traditional algorithms, which are tailored for ideal gas EoS and struggle to accommodate the inherent variations. A comparative analysis with macroscopic efficient central solvers designed to be independent of the eigen-structure, such as MOVERS+ and RICCA, is conducted to validate the results against benchmark tests from the data in the literature. It is important to note that the kinetic schemes also possess the advantage of being independent of the eigen-structure, a feature that distinguishes them from traditional Riemann solvers. This effort significantly enhances computational modelling capabilities and fosters deeper insights into the behaviour of dense gases. The proposed advancements enhance numerical methods tailored for real gas EoS simulations by ensuring precise capture of grid-aligned steady discontinuities and effectively mitigating numerical diffusion across these discontinuities in inviscid compressible flows.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"290 ","pages":"Article 106539"},"PeriodicalIF":2.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On solving for shocks and travelling waves using a quantum algorithm","authors":"Biswajit Basu ,&nbsp;Andrea Staino ,&nbsp;Frank Gaitan","doi":"10.1016/j.compfluid.2025.106559","DOIUrl":"10.1016/j.compfluid.2025.106559","url":null,"abstract":"<div><div>In this paper, we solve for shocks and travelling waves in advection, inviscid Burgers’ and Burgers’ equations by implementing a recently established quantum algorithm in the literature. The quantum algorithm has been successful in solving Navier–Stokes, flow generated by Burgers’ and submarine tephra flow equations under certain initial and boundary conditions. Here, we further study the efficacy of the quantum algorithm by extending the application to advection, inviscid Burgers’ and Burgers’ equations under different kinds of initial and boundary conditions. In addition to central differencing and upwinding, Lax–Wendroff discretization scheme has also been introduced in the quantum algorithm to observe how numerical dissipation and dispersion are affected. We recover known travelling waves, and shocks with rarefaction and expansion.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"290 ","pages":"Article 106559"},"PeriodicalIF":2.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unsupervised extraction of rotational Lagrangian coherent structures","authors":"Marius M. Neamtu-Halic ,&nbsp;Stefano Brizzolara ,&nbsp;George Haller ,&nbsp;Markus Holzner","doi":"10.1016/j.compfluid.2025.106558","DOIUrl":"10.1016/j.compfluid.2025.106558","url":null,"abstract":"<div><div>Lagrangian coherent structures (LCSs) are widely recognized as playing a significant role in turbulence dynamics since they can control the transport of mass, momentum or heat. However, the methods used to identify these structures are often based on ambiguous definitions and arbitrary thresholding. While LCSs theory provides precise and frame-indifferent mathematical definitions of coherent structures, some of the commonly used extraction algorithms employed in the literature are still case-specific and involve user-defined parameters. In this study, we present a new, unsupervised extraction algorithm that enables the extraction of rotational LCSs based on Lagrangian average vorticity deviation from an arbitrary 3D velocity field. The algorithm utilizes two alternative methods for the identification of the LCS core (ridge): an unsupervised clustering method and a streamline-based method. In a subsequent step, the ridge curve is parametrized through a pruning procedure of minimum spanning tree graphs. To assess the effectiveness of the algorithm, we test it on two cases: (i) direct numerical simulations of forced homogeneous and isotropic turbulence and (ii) three-dimensional Particle Tracking Velocimetry experiments of a turbulent gravity current.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"290 ","pages":"Article 106558"},"PeriodicalIF":2.5,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143237931","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 Staggered Lattice Boltzmann Method for the Radiative Transfer Equation","authors":"R. Ruyssen ,&nbsp;R. Cottereau ,&nbsp;P. Boivin","doi":"10.1016/j.compfluid.2025.106555","DOIUrl":"10.1016/j.compfluid.2025.106555","url":null,"abstract":"<div><div>This paper introduces a method for the numerical approximation of solutions of the mono-kinetic Radiative Transfer Equation, adapting some of the Lattice Boltzmann Method features. The main difference between the Radiative Transfer Equation and the Boltzmann Equation, used in the classical Lattice Boltzmann Method framework, lies in the constrained norm of the velocity field appearing in the advection operator. This small difference leads to <em>off-grid</em> propagation if one uses a regular lattice, as classically done for efficiency reasons. To recover on-grid propagation, this paper introduces a specific time discretization along each propagation directions and an original traversal algorithm to allow for scattering between different directions at common times. The algorithm involves only linear time interpolations so as to preserve the local nature of the Lattice Boltzmann Method. The direction quadrature follows the principles of the Discrete Ordinate Method. The relevance of the approach is illustrated on different two-dimensional problems and the results are compared to previously published numerical test-cases.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"290 ","pages":"Article 106555"},"PeriodicalIF":2.5,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166250","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":"High-order, refinement-based computation of the volume of an arbitrary polyhedron intersected by an implicitly defined fluid body","authors":"Joaquín López","doi":"10.1016/j.compfluid.2025.106556","DOIUrl":"10.1016/j.compfluid.2025.106556","url":null,"abstract":"<div><div>A high-order accurate, efficient and easy-to-implement method is presented for computing the fluid volume bounded by an arbitrary polyhedron, whether it is convex or non-convex, and an implicitly-defined fluid body. This method is an improved version of a previous one that used a recursive local grid refinement of the polyhedron and linear interpolations to determine the intersections of the interface that delimits the fluid body (or simply fluid-body interface) with the polyhedron boundaries. The proposed method first determines the volume of a polyhedral approximation of the bounded fluid region by using a general clipping-lookup and capping procedure valid for arbitrary polyhedra, where the points of intersection between the polyhedron and the fluid-body interface are obtained using a root-finding method rather than linear interpolations. The approximated polyhedral volume is subsequently corrected by using simple Gaussian quadrature rules over a triangulated approximation of the intersected fluid-body interface to achieve high-order accuracy. Recursive local grid refinement of the polyhedron also enables reductions in fluid volume errors. The proposed method requires no assumption of any particular local parametrization of the fluid-body interface, whether paraboloidal or of any other type, or deriving any complex analytical expressions to compute the volume of fluid contained within the polyhedron, thereby making the method easy to implement and generally applicable to any implicitly-defined function. A detailed assessment shows global fourth-order convergent accuracies on structured and unstructured grids even for complex fluid-body interfaces of a high degree. Speedups of several orders of magnitude with respect to the previous refinement method with linear interpolations are achieved even for relatively coarse grids. Comparisons with other methods are also presented, and the software with the implemented method and tests used for the assessment is freely available.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"289 ","pages":"Article 106556"},"PeriodicalIF":2.5,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical timescale effects on detonation convergence","authors":"Shivam Barwey ,&nbsp;Michael Ullman ,&nbsp;Ral Bielawski ,&nbsp;Venkat Raman","doi":"10.1016/j.compfluid.2025.106550","DOIUrl":"10.1016/j.compfluid.2025.106550","url":null,"abstract":"<div><div>Numerical simulations of detonation-containing flows have emerged as crucial tools for designing next-generation power and propulsion devices. As these tools mature, it is important for the combustion community to properly understand and isolate grid resolution effects when simulating detonations. To this end, the objective of this work is to provide a comprehensive analysis of the numerical convergence of unsteady detonation simulations, with focus on isolating the impacts of chemical timescale modifications on convergence characteristics in the context of operator splitting. With the aid of an AMReX-based adaptive mesh refinement flow solver (Sharma et al., 2024)—which enables resolutions up to <span><math><mrow><mi>O</mi><mrow><mo>(</mo><mn>1000</mn><mo>)</mo></mrow></mrow></math></span> cells-per-induction length—the convergence analysis is conducted using two kinetics configurations: (1) the simplified three-step Arrhenius-based model mechanism of Short and Quirk (1997), where chemical timescales in the detonation are modified by adjusting activation energies in the initiation and branching reactions, and (2) a detailed hydrogen-air mechanism (Mével et al. (2009), Shepherd (2018)), where the chemical timescales are adjusted by varying the ambient pressure. The convergence of unsteady self-sustained detonations in one-dimensional channels is then analyzed with reference to steady-state theoretical baseline solutions using these mechanisms. The goal of the analysis is to provide a detailed comparison of the effects of grid resolution on both macroscopic (peak pressures and wave speeds) and microscopic (wave structure) quantities of interest, drawing connections between the deviations from steady-state baselines and minimum chemical timescales. In particular, chemical timescale reductions were found to have minimal impact on the convergence of macroscopic properties. However, analyses of microscopic convergence trends, particularly in the reaction front location, revealed a key insight: maintaining the induction time while eliminating prohibitive chemical timescales through mechanism simplifications and combustion modeling can significantly enhance detonation convergence properties. Ultimately, this work uncovers resolution-dependent unsteady detonation convergence regimes and highlights the important role played by not only the chemical timescales, but also the ratio between the chemical timescale and induction time on the numerical convergence of the detonation wave structure.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"289 ","pages":"Article 106550"},"PeriodicalIF":2.5,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147858","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 generalized correction scheme for two-way coupled particle-laden Euler–Lagrange simulations","authors":"Thota Srinivas,&nbsp;Gaurav Tomar","doi":"10.1016/j.compfluid.2025.106554","DOIUrl":"10.1016/j.compfluid.2025.106554","url":null,"abstract":"<div><div>A two-way coupled, <span><math><mrow><mn>3</mn><mi>D</mi></mrow></math></span>, Euler–Lagrange point particle formulation is proposed that takes into consideration the disturbance in the flow caused by the dispersed particles to obtain the undisturbed fluid flow field essential for the accurate computation of force closure models. Specifically, an advection–diffusion–reaction (ADR) equation for Stokes flow developed by Pakseresht and Apte (Pakseresht and Apte, 2021) for obtaining the disturbance flow field created by the particle is extended to non-Stokesian flow conditions. Using the solution for flow over a cylinder, an ADR equation for obtaining the disturbance flow field created by a particle in pseudo-<span><math><mrow><mn>2</mn><mi>D</mi></mrow></math></span> flows is derived. The present technique for non-Stokesian flows performs significantly better than the existing Stokesian correction scheme, especially for higher particle Stokes numbers and particle-to-grid spacing ratios. The extension of the present technique to the porous particles is examined using two test cases, namely, the settling of porous particles under gravity in a quiescent fluid and porous particles subjected to the oscillating body force field. The present technique is straightforward to implement in all existing Euler–Lagrange solvers based on either ADR or zonal-advection–diffusion–reaction (Zonal-ADR) model.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"290 ","pages":"Article 106554"},"PeriodicalIF":2.5,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167512","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":"Mixed subfilter-scale models for large-eddy simulation of decaying isotropic turbulence using an artificial neural network","authors":"Dong Li ,&nbsp;Lei Yang ,&nbsp;Kai Zhang ,&nbsp;Kun Luo ,&nbsp;Jianren Fan","doi":"10.1016/j.compfluid.2025.106557","DOIUrl":"10.1016/j.compfluid.2025.106557","url":null,"abstract":"<div><div>This study is concerned with the development of a new subfilter-scale (SFS) stress model for large-eddy simulation (LES) of decaying isotropic turbulence using an artificial neural network (ANN). Both <em>a priori</em> and <em>a posteriori</em> tests are performed to investigate the effect of input variables on the performance of ANN-based SFS models. Within the range of parameters and flow types considered, the ANN-based model with filtered strain-rate tensor as input is found to show excellent predictions of the resolved statistics in <em>a posteriori</em> test, although it provides low correlation coefficients between the true and predicted SFS stresses in <em>a priori</em> test. However, this model performs poorly in the predictions of the SFS statistics and backscatter. On the other hand, the predictive accuracy of ANN-based models is significantly improved by using a combination of the strain-rate tensor and the modified Leonard stress tensor as input variables. The proposed ANN-based mixed SFS model not only can predict the backscatter, but also exhibits better performance in predicting the resolved and SFS statistics than the traditional dynamic models. In particular, the ANN-based mixed model shows an advantage over the dynamic two-parameter mixed model in terms of the accuracy and computational efficiency.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"289 ","pages":"Article 106557"},"PeriodicalIF":2.5,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147861","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":"Modeling plant canopy through numerical simulation of cylindrical array","authors":"Ning Huang,&nbsp;Jialiang Sun,&nbsp;Yuhao Zhao,&nbsp;Jie Zhang,&nbsp;Binbin Pei","doi":"10.1016/j.compfluid.2025.106551","DOIUrl":"10.1016/j.compfluid.2025.106551","url":null,"abstract":"<div><div>Vegetation is frequently utilized in windbreak engineering, yet the flow characteristics in the wake region and its interactions with airflow remain unresolved due to the heterogeneous geometry of canopy. By simplifying the canopy structure geometry as an array of cylinders with varying porosity, this works aims to reveal the flow characteristics and turbulence in the wake region of canopy flow using Large-Eddy Simulation. Meanwhile, the cylinder array is simplified using a porous-media model simulated by the k-epsilon turbulence model. A comparison of the two numerical methods reveals that employing the porous media model yields a better computational efficiency without much effect on the accuracy of the simulated steady flow region. More specifically, the RANS coupled with porous media model improves the computational efficiency by four times, while the maximal deviation in the steady flow region approaches 11%. We also analyze the dynamic mechanisms of turbulence structures in the wake region of the cylindrical array, and how vorticity fields vary with porosity. It is found that the increase in canopy porosity enlarge its protected area. Finally, an empirical model suitable for canopy vegetation is presented by analyzing the relationship between porosity and resistance coefficient.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"289 ","pages":"Article 106551"},"PeriodicalIF":2.5,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147893","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}