International Journal for Numerical Methods in Fluids最新文献

{"title":"Comparison of Numerical Methods for Geometric Warpage Compensation","authors":"Steffen Tillmann,&nbsp;Stefan Basermann,&nbsp;Stefanie Elgeti","doi":"10.1002/fld.5404","DOIUrl":"https://doi.org/10.1002/fld.5404","url":null,"abstract":"<p>In injection molding processes, shrinkage and warpage cause deviations in the size and shape of produced parts compared to the cavity shape. While shrinkage is due to the change of material density during solidification, warpage is caused by uneven cooling and internal stresses within the part. One approach to mitigate these effects is by adjusting the cavity shape to anticipate the deformation. While finding the optimal cavity shape is often experience-based in practice, numerical design optimization can greatly assist in this process. In this study, we evaluate various numerical algorithms from existing literature to identify the optimal cavity shape. Each method is briefly outlined regarding how it adapts the geometry, and we discuss their respective strengths and weaknesses for different scenarios. We conduct comparisons using 3D geometries of varying complexity. Our findings demonstrate that, for geometric warpage compensation, the node-based reverse geometry method yields the least warpage and is computationally cost-effective. Furthermore, it is straightforward to implement and consistently performs well across different geometries.</p>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 9","pages":"1280-1288"},"PeriodicalIF":1.8,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/fld.5404","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144768129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Extrapolation Boundary Conditions for 2-D Smoothed Particle Hydrodynamics","authors":"Hossein Mahdizadeh,&nbsp;Colin D. Rennie,&nbsp;Benedict D. Rogers,&nbsp;Abolghasem Pilechi","doi":"10.1002/fld.5397","DOIUrl":"https://doi.org/10.1002/fld.5397","url":null,"abstract":"<p>This paper presents a new robust treatment for smoothed particle hydrodynamics (SPH) open (inflow/outflow) and solid boundary conditions, avoiding the unphysical fluctuations and numerical noise present in existing techniques. By novel use of concepts from finite volume methods, the fluid properties from sequential dynamic particles with different normal distances to the boundaries are extrapolated to ghost particles. No so-called mirror points are required, making the method computationally efficient and easy to implement. The new methodology is validated through a series of progressively challenging test cases. The effectiveness of the wall and inflow-outflow boundaries is evaluated for 2-D Poiseuille laminar flow. The performance of the wall boundary for complex geometries is demonstrated using a hydrostatic tank with a triangular wedge, followed by a conventional 2-D dam-break problem to capture impact pressures. A range of challenging vertical inflows rarely explored using SPH, with varying efflux velocities, demonstrate highly accurate performance of the boundary treatment, with results compared to STAR-CCM+. Finally, the robust performance is demonstrated for flow past circular and square cylinders over a range of Reynolds numbers, showing excellent results compared to reference results.</p>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 9","pages":"1248-1279"},"PeriodicalIF":1.8,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/fld.5397","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144767912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Linear Discontinuity Sharpening for Highly Resolved and Robust Magnetohydrodynamics Simulations","authors":"Tomohiro Mamashita,&nbsp;Gaku Fukushima,&nbsp;Keiichi Kitamura","doi":"10.1002/fld.5402","DOIUrl":"https://doi.org/10.1002/fld.5402","url":null,"abstract":"<p>This study applies a reconstruction scheme, “hybrid MUSCL–THINC” for finite volume methods developed by Chiu et al., to magnetohydrodynamics (MHD) simulations. The scheme is a hybrid of monotone upstream-centered schemes for conservation law (MUSCL) and a tangent of hyperbola interface capturing (THINC) scheme. THINC sharply captures discontinuous distributions of physical quantities by using a hyperbolic tangent function. Our investigation reveals that hybrid MUSCL–THINC is more oscillatory in MHD simulations than in gas dynamics simulations, owing to the greater number of physical variables and associated complex waves in MHD. Analytical results demonstrate that artificial compression by THINC is excessive for MHD shock waves, whereas it is effective for linear discontinuities, such as contact discontinuities. Therefore, we propose a modification in which the artificial compression by THINC is weakened in the vicinity of nonlinear discontinuities and applied only to linear regions. The new scheme is tested using one- and two-dimensional MHD problems, and the results demonstrate that the scheme sharply captures linear discontinuities while avoiding numerical oscillations due to excessive artificial compression.</p>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 9","pages":"1226-1247"},"PeriodicalIF":1.8,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/fld.5402","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144767915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"A Framework Unifying Three-Cell-Based Scale-Invariant Exponential and Trigonometric WENO Weighting Functions With Optimal Shape Parameters","authors":"Xi Deng,&nbsp;Zhen-hua Jiang,&nbsp;Bin Xie,&nbsp;Chao Yan","doi":"10.1002/fld.5401","DOIUrl":"https://doi.org/10.1002/fld.5401","url":null,"abstract":"<div>\u0000 \u0000 <p>Exponential and trigonometric functions have been extensively employed as the kernel of reconstruction operators within numerous WENO (Weighted Essentially Non-oscillatory) schemes to accelerate the convergence rate. However, most of them are scale-dependent, compromising the robustness required for multi-scale flow simulations. Thus, this work aims to develop novel three-cell-based scale-invariant WENO schemes that use exponential and trigonometric functions as the kernel of non-linear weights. First, to achieve the scale-invariant property, this work reformulates the newly proposed scale-invariant ROUND (Reconstruction Operators in Unified Normalized-variable Diagram) schemes into the form of WENO weighting functions, thereby facilitating the design of scale-invariant WENO schemes. Then, this work proposes new WENO non-linear weights using exponential and trigonometric functions—such as Gaussian, hyperbolic, and cosine functions—to enhance the accuracy of the three-cell-based WENO scheme. The proposed WENO weights contain a shape parameter that controls the errors between the non-linear weight and the ideal weight. As the value of the shape parameter increases, the non-linear weight converges towards the ideal weight but also becomes more likely to produce numerical oscillations. To approximate the optimal value of the shape parameter, the WENO reconstruction operator is projected into normalized variable space, and the shape parameters are fine-tuned to ensure the normalized reconstruction operator falls into the CBC (Convection Bounded Criterion) region of UND (Unified Normalized-variable Diagram). The accuracy analysis reveals that the proposed weighting functions outperform classical WENO schemes, particularly when the smooth function contains a first-order critical point. The accuracy and shock-capturing properties of the proposed schemes are further validated through benchmark tests. Thus, this work demonstrates using the ROUND framework to design scale-invariant three-cell-based WENO schemes with exponential and trigonometric functions and optimal shape parameters.</p>\u0000 </div>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 9","pages":"1209-1225"},"PeriodicalIF":1.8,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144767490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Description and Convergence Order Analysis of the Finite Element-Volume Spatial Discretization Method","authors":"Maria Adela Puscas,&nbsp;Pierre-Emmanuel Angeli,&nbsp;Nathalie Nouaime,&nbsp;Erell Jamelot","doi":"10.1002/fld.5399","DOIUrl":"https://doi.org/10.1002/fld.5399","url":null,"abstract":"<p>This article reviews the Finite Element-Volume spatial discretization method on tetrahedral meshes implemented in the TrioCFD code. TrioCFD is a computational fluid dynamics software specifically designed for simulating turbulent flows and heat transfer, with a primary focus on nuclear engineering applications. Its versatility also extends to a wide range of engineering applications. This article presents the principles of Finite Element-Volume discretization and conducts an analysis of its properties and convergence orders. The time scheme can be explicit or semi-implicit, and the velocity and pressure are updated based on a projection-correction scheme. The discretization ensures local mass conservation, second-order convergence for velocity, and first-order convergence for pressure. Moreover, a super-convergence is achieved in two-dimension when the source term is a gradient. The accuracy and convergence rate of the numerical method is rigorously assessed in a variety of two- and three-dimensional test cases, including steady Stokes and Navier–Stokes problems with manufactured solutions. The classical lid-driven cavity flow is also addressed, and the results of comparisons between the solutions from the present numerical method and the results of reference literature are provided.</p>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 9","pages":"1189-1208"},"PeriodicalIF":1.8,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/fld.5399","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144767488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"PolyMAC: A Staggered Finite Volume Method on General Meshes for Incompressible Navier-Stokes Equations","authors":"Pierre-Loïc Bacq,&nbsp;Antoine Gerschenfeld,&nbsp;Michael Ndjinga","doi":"10.1002/fld.5398","DOIUrl":"https://doi.org/10.1002/fld.5398","url":null,"abstract":"<div>\u0000 \u0000 <p>We consider the numerical resolution of the incompressible Navier-Stokes equations. We present a new compatible Finite Volume discretisation that generalises the famous Marker-and-Cell (MAC) method to polyhedral meshes that we call PolyMAC. In the first part of the paper, we recall the principles of compatible schemes and detail the key operators of the discretisation. The convergence and robustness of PolyMAC are assessed numerically first on a benchmark from the FVCA conferences. We then consider a problem of industrial complexity that allows us to confirm the robustness of PolyMAC on more complex problems. The second part of the article is dedicated to the efficient numerical resolution of the resulting linear system. Concretely, we use a PISO-like prediction-correction approach and develop efficient preconditioners for linear systems. In particular, we show that the saddle-point system arising from the correction step is very challenging for iterative methods on distorted meshes. In this work, we develop a robust preconditioner based on an algebraic transformation of the system. In particular, this new preconditioner shows impressive convergence on problems of industrial complexity.</p>\u0000 </div>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 9","pages":"1171-1188"},"PeriodicalIF":1.8,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144768087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Retraction: An Efficient Parallel Algorithm for Three-Dimensional Analysis of Subsidence Above Gas Reservoirs","authors":"","doi":"10.1002/fld.5396","DOIUrl":"https://doi.org/10.1002/fld.5396","url":null,"abstract":"<p>\u0000 <span>B.A. Schrefler</span>, <span>X. Wang</span>, <span>V.A. Salomoni</span>, and <span>G. Zuccolo</span>, “ <span>An Efficient Parallel Algorithm for Three-Dimensional Analysis of Subsidence Above Gas Reservoirs</span>,” <i>International Journal for Numerical Methods in Fluids</i> <span>31</span>, no. <span>1</span> (<span>1999</span>): <span>247</span>–<span>260</span>, \u0000https://doi.org/10.1002/(SICI)1097-0363(19990915)31:1&lt;247::AID-FLD966&gt;3.0.CO;2-D.</p><p>The above article, published online on 14 September 1999 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors; the journal Editor-in-Chief, Alina Bruma; and John Wiley &amp; Sons Ltd. The retraction has been agreed due to the authors' discovery that the proper permissions for use of Table 1 and Figures 4, 5, 6, 7, and 8 were not obtained prior to publication. As it was not possible to obtain retrospective permission, the article must therefore be retracted.</p>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 8","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/fld.5396","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144525185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Vortex Panel Method in Axisymmetric Cylindrical Coordinates: Inviscid Formulation","authors":"Suguru Shiratori,&nbsp;Kosuke Kimata,&nbsp;Masaya Katoh,&nbsp;Hideaki Nagano,&nbsp;Kenjiro Shimano","doi":"10.1002/fld.5400","DOIUrl":"https://doi.org/10.1002/fld.5400","url":null,"abstract":"<p>This study addresses the vortex panel method, which is an efficient solution for inviscid flow around a body. For Cartesian coordinates, the panel method has been developed and widely applied. However, a formulation has not been proposed for axisymmetric cylindrical coordinates. This study derives a Green's function corresponding to the governing equation of the potential flow in axisymmetric cylindrical coordinates by modifying the Green's function provided by Cohl and Tohline [doi:10.1086/308062]. The derived Green's function <span></span><math>\u0000 \u0000 <semantics>\u0000 <mrow>\u0000 <mi>G</mi>\u0000 </mrow>\u0000 <annotation>$$ G $$</annotation>\u0000 </semantics></math> is significantly compact and is composed of a single term of the half-integer degree Legendre function of the second type. The derivation of Green's function <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>G</mi>\u0000 </mrow>\u0000 <annotation>$$ G $$</annotation>\u0000 </semantics></math> is confirmed by analytically evaluating the requirement <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ℒ</mi>\u0000 <mi>G</mi>\u0000 <mo>=</mo>\u0000 <mn>0</mn>\u0000 </mrow>\u0000 <annotation>$$ mathit{mathcal{L}G}=0 $$</annotation>\u0000 </semantics></math>, where <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ℒ</mi>\u0000 </mrow>\u0000 <annotation>$$ mathcal{L} $$</annotation>\u0000 </semantics></math> is a linear operator of the governing equation. Under the derived <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>G</mi>\u0000 </mrow>\u0000 <annotation>$$ G $$</annotation>\u0000 </semantics></math>, the vortex panel method is formulated by discretizing the vorticity distribution along the body surface. The validity of the constructed panel method is confirmed through calculations of the flow past a sphere, an ellipsoid, a torus, and a teardrop-like object by comparison with analytical or numerical solutions.</p>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 9","pages":"1161-1170"},"PeriodicalIF":1.8,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/fld.5400","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144767933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Comparative Analysis of Reinforcement Learning Agents for Optimizing Airfoil Shapes","authors":"Harsh H. Sawant,&nbsp;Rahul Gujar,&nbsp;Neeta Mandhare,&nbsp;M. J. Sable,&nbsp;Prashant K. Ambadekar,&nbsp;S. H. Gawande","doi":"10.1002/fld.5395","DOIUrl":"https://doi.org/10.1002/fld.5395","url":null,"abstract":"<div>\u0000 \u0000 <p>This work investigates the optimization of airfoil shapes using various reinforcement learning (RL) algorithms, including Deep Deterministic Policy Gradient (DDPG), Twin Delayed Deep Deterministic Policy Gradient (TD3), and Trust Region Policy Optimization (TRPO). The primary objective is to enhance the aerodynamic performance of airfoils by maximizing lift forces across different angles of attack (AoA). The study compares the optimized airfoils against the standard NACA 2412 airfoil. The DDPG-optimized airfoil demonstrated superior performance at lower and moderate AoAs, while the TRPO-optimized airfoil excelled at higher AoAs. In contrast, the TD3-optimized airfoil consistently underperformed. The results indicate that RL algorithms, particularly DDPG and TRPO, can effectively improve airfoil designs, offering substantial benefits in lift generation. This paper underscores the potential of RL techniques in aerodynamic shape optimization, presenting significant implications for aerospace and related industries.</p>\u0000 </div>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 8","pages":"1142-1156"},"PeriodicalIF":1.7,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144524550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modified CIP-Soroban Method and Its Application in Implosion Process of Inertial Confinement Fusion","authors":"Zhehao Lin,&nbsp;Kazumasa Takahashi,&nbsp;Toru Sasaki,&nbsp;Takashi Kikuchi,&nbsp;Atsushi Sunahara","doi":"10.1002/fld.5392","DOIUrl":"https://doi.org/10.1002/fld.5392","url":null,"abstract":"<div>\u0000 \u0000 <p>The CIP-Soroban method is an excellent adaptive meshless method capable of solving advection problems with 3rd-order accuracy by combining the Constrained Interpolation Profile/Cubic Interpolated Pseudo-particle (CIP) method. This study proposes a modified version of the CIP-Soroban method specifically designed to address severe compressible hydrodynamic scenarios. The proposed method includes a material distinguishing approach, incorporates a modified form of monitoring functions for grid generation, utilizes a staggered grid arrangement, incorporates the Maximum and minimum Bounds method, solves non-advection terms using a finite difference method, and employs an adjusted procedure for stably solving the governing equations. We applied the modified CIP-Soroban method to simulate the implosion process in inertial confinement fusion (ICF), which is commonly modeled by compressible fluid and has the problems of large gradients of physical values and strong nonlinearity for stable and accurate numerical analysis. Implosion simulations were performed using a series of grids with increasing resolutions, ranging from coarse to fine grid settings, as one of the application examples. The results indicated that compared to the conventional uniform grid CIP method, the modified CIP-Soroban method reduced computational costs (calculation time, memory occupancy, and grid number) for obtaining the same precision results.</p>\u0000 </div>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 8","pages":"1120-1141"},"PeriodicalIF":1.7,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144524883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}