Computers & Fluids最新文献

{"title":"Optimizing fluid mixing in channel flow using wall-mounted flexible structures","authors":"Gaurav Singh ,&nbsp;Arahata Senapati ,&nbsp;Arnab Atta ,&nbsp;Rajaram Lakkaraju","doi":"10.1016/j.compfluid.2025.106590","DOIUrl":"10.1016/j.compfluid.2025.106590","url":null,"abstract":"<div><div>In channel mixers with two parallel streams of fluid, mixing is achieved by either laminar diffusion at low Reynolds numbers or from flow agitation due to geometric variations. Traditionally, rigid obstructions or textures are used in various spatial arrangements to improve fluid mixing. In our work, we have numerically investigated the mixing performance of a passive scalar in a two-dimensional channel flow accompanied by wall-mounted flexible plates as obstructions for a wide range of low Reynolds numbers (<span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span>). The thin plates are arranged on opposite walls of the channel, and the distance between them is varied in the range <span><math><mrow><mn>0</mn><mi>h</mi></mrow></math></span> to <span><math><mrow><mn>2</mn><mi>h</mi></mrow></math></span>, where <span><math><mi>h</mi></math></span> is the channel lateral width. The different arrangements result in corresponding flow paths, thereby affecting fluid mixing and flow rate due to the pressure head losses. We assessed the mixing performance in the channel via the mixing index and the head loss. Our results show that the channel with the two plates when arranged exactly opposite the walls (without a separation gap), offers the highest mixing with significant pressure drop. In contrast, either a single plate or two plates widely separated result in nearly similar levels of mixing index with a lower head loss. We devised a performance index based on a cost-benefit analogy by comparing the flexible plate configurations with the plane channel (i.e, without any obstruction) so as to assess the mixing effectiveness and found that a single flexible plate in the channel in the flow conditions with <span><math><mrow><mi>R</mi><mi>e</mi><mo>≈</mo><mn>400</mn></mrow></math></span> suit the best for the mixing of two fluid in the channel.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"291 ","pages":"Article 106590"},"PeriodicalIF":2.5,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519699","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":"An adaptive solver for accurate simulation of multicomponent shock-interface problems for thermally perfect species","authors":"Yuqi Wang ,&nbsp;Ralf Deiterding ,&nbsp;Jianhan Liang","doi":"10.1016/j.compfluid.2025.106587","DOIUrl":"10.1016/j.compfluid.2025.106587","url":null,"abstract":"<div><div>A second-order-accurate finite volume method, hybridized by blending an extended double-flux algorithm and a traditionally conservative scheme, is developed. In this scheme, hybrid convective fluxes and hybrid interpolation techniques are designed to ensure stability and accuracy in the presence of both material interfaces and shocks. Two approaches, extended from the original double-flux model, are presented to eliminate the well-known ”pressure oscillation” phenomenon at material interfaces observed with the traditional conservative scheme. Numerous verification simulations confirm that the method can handle multi-dimensional shock-interface problems reliably and efficiently, even in the presence of viscous and reactive terms.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"291 ","pages":"Article 106587"},"PeriodicalIF":2.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479052","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 differentiated geometry blade parameterization methodology for gas turbines","authors":"Christian Voß ,&nbsp;Martin Siggel ,&nbsp;Jan Backhaus ,&nbsp;Georgios Goinis ,&nbsp;Andreas Pahs","doi":"10.1016/j.compfluid.2025.106588","DOIUrl":"10.1016/j.compfluid.2025.106588","url":null,"abstract":"<div><div>The present paper is about the turbomachinery blade geometry parameterization, which has been developed at the DLR Institute of Propulsion Technology for the last two decades. It was implemented into the software BladeGen, which is used to design blades and vanes for axial and radial compressors as well as for fans, propellers and turbines. The parameterization uses typical geometric variables such as characteristic angles and lengths in combination with B-spline parameters like control points and knot vectors to generate a variable number of two-dimensional profile-sections, which are transformed by a conformal mapping into three-dimensional space and connected via NURBS surfaces to form blade surfaces and solids. This publication presents the application philosophy and some parameterization and implementation details. The intuitive handling and some software enhancements such as algorithmic differentiation capabilities are also demonstrated by application examples.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"292 ","pages":"Article 106588"},"PeriodicalIF":2.5,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143548545","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":"An efficient class of increasingly high-order ENO schemes with multi-resolution","authors":"Hua Shen","doi":"10.1016/j.compfluid.2025.106589","DOIUrl":"10.1016/j.compfluid.2025.106589","url":null,"abstract":"<div><div>We construct an efficient class of increasingly high-order (up to 17th-order) essentially non-oscillatory schemes with multi-resolution (ENO-MR) for solving hyperbolic conservation laws. The candidate stencils for constructing ENO-MR schemes range from the first-order one-point stencil increasingly up to the designed very high-order stencil. The proposed ENO-MR schemes adopt a simple and efficient strategy that only requires the computation of the highest-order derivatives of a part of candidate stencils. Theoretical analysis and numerical computations indicate that ENO-MR schemes achieve designed high-order convergence in smooth regions which may contain high-order critical points (local extrema) and retain ENO property for strong shocks. Moreover, the performance of ENO-MR schemes does not depend on the scale of the solutions.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"291 ","pages":"Article 106589"},"PeriodicalIF":2.5,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509146","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":"Incremental singular value decomposition based model order reduction of scale resolving fluid dynamic simulations","authors":"Niklas Kühl","doi":"10.1016/j.compfluid.2025.106579","DOIUrl":"10.1016/j.compfluid.2025.106579","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Scale-resolving flow simulations often feature several million [thousand] spatial [temporal] discrete degrees of freedom. When storing or re-using these data, e.g., to subsequently train some sort of data-based surrogate or compute consistent adjoint flow solutions, a brute-force storage approach is practically impossible. Therefore, – mandatory incremental – Reduced Order Modeling (ROM) approaches are an attractive alternative since only a specific time horizon is effectively stored, usually aligned with the amount of fast available, e.g., Random Access Memory (RAM). This bunched flow solution is then used to enhance the already computed ROM so that the allocated memory can be released and the procedure repeats.&lt;/div&gt;&lt;div&gt;This paper utilizes an incremental truncated Singular Value Decomposition (itSVD) procedure to compress flow data resulting from scale-resolving flow simulations. To this end, two scenarios are considered, referring to an academic Large Eddy Simulation (LES) around a circular cylinder at &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Re&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;mi&gt;⋅&lt;/mi&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; as well as an industrial case that employs a hybrid filtered/averaged Detached Eddy Simulation (DES) on the flow around the superstructure of a full-scale feeder ship at &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Re&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;L&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mi&gt;⋅&lt;/mi&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;8&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;.&lt;/div&gt;&lt;div&gt;The paper’s central focus is on an aspect of severe practical relevance: how much information of the computed scale-resolving solution should be used by the ROM, i.e., how much redundancy occurs in the resolved turbulent fluctuations that favors ROM. In the course of the tSVD employed, this goes hand in hand with the question of ”how many singular values of the flow-solution-snapshot-matrix should be neglected (or considered)” – without (a) re-running the simulation several times in a try-and-error procedure and (b) still obtain compressed results below the model and discretization error. An adaptive strategy is utilized, which features two comparatively simple adjusting screws, for which appropriate decision support is provided. Next to a general feasibility study, reported results show the capability to obtain a fully adaptive data reduction of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mn&gt;95&lt;/mn&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; percent via a computational overhead of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; percent with a mean accuracy of reconstructed local and global flow data of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/m","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"291 ","pages":"Article 106579"},"PeriodicalIF":2.5,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471388","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":"Break-up of the Taylor bubble","authors":"Evgenii L. Sharaborin ,&nbsp;Oleg A. Rogozin ,&nbsp;Aslan R. Kasimov","doi":"10.1016/j.compfluid.2025.106577","DOIUrl":"10.1016/j.compfluid.2025.106577","url":null,"abstract":"<div><div>High-resolution direct numerical simulation is used to study the motion of a Taylor bubble in a cylindrical microtube under conditions that lead to the bubble break-up. It is observed that the initial bubble elongates and deforms such that its front part retains a bullet-like shape while its back part forms a skirt shape. Subsequently, the carrier fluid surrounded by the skirt penetrates into the bubble forming a finger that transitions into a bulb shape. The bulb then increases in size until it touches the near-wall liquid film and as a result splits the bubble into two comparable daughter bubbles. Various dynamical features of this break-up process are explored and described in detail.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"291 ","pages":"Article 106577"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474058","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 data-driven actuator-line methodology for the simulation of high-lift aircraft wake systems","authors":"S. Bennie ,&nbsp;P. Nagy ,&nbsp;M. Fossati","doi":"10.1016/j.compfluid.2025.106578","DOIUrl":"10.1016/j.compfluid.2025.106578","url":null,"abstract":"<div><div>The actuator-line method is here integrated with a data-driven approach for the investigation of aircraft-induced trailing vortices as generated by landing and take-off configurations with varying levels of high-lift device deflections. It is shown that through coupling the Actuator-Line-Method to a suitable Reduced-Order-Model built upon spanwise aerodynamic force distributions obtained from high-fidelity CFD solution data. The resulting wake from the geometry can be reproduced in a manner that no longer requires an explicit representation of the aircraft geometry within the simulation environment. The result is a method that allows for increased fidelity in the vortex farfield when studying the relevant wake dynamics and evolution during take-off, climb, approach and landing. The accuracy of the proposed method is assessed via a direct comparison to traditional high-fidelity nearfield derived results where it was observed that the induced downstream velocity profile and resulting location of vortex structures displayed a satisfactory level of agreement. With the creation of such a method, the effects of variations in aircraft high-lift deployment can be included within the simulation of downstream vortex pairs in a manner that respects the computational limitations of current hardware.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"291 ","pages":"Article 106578"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471337","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":"Topology optimization for particle flow problems using Eulerian-Eulerian model with a finite difference method","authors":"Chih-Hsiang Chen,&nbsp;Kentaro Yaji","doi":"10.1016/j.compfluid.2025.106573","DOIUrl":"10.1016/j.compfluid.2025.106573","url":null,"abstract":"<div><div>Particle flow processing is widely employed across various industrial applications and technologies. Due to the complex interactions between particles and fluids, designing effective devices for particle flow processing is challenging. In this study, we propose a topology optimization method to design flow fields that effectively enhance the resistance encountered by particles. Particle flow is simulated using an Eulerian–Eulerian model based on a finite difference method. Automatic differentiation is implemented to compute sensitivities using a checkpointing algorithm. We formulate the optimization problem as maximizing the variation of drag force on particles while reducing fluid power dissipation. Initially, we validate the finite difference flow solver through numerical examples of particle flow problems and confirm that the corresponding topology optimization produces a result comparable to the benchmark problem. In the optimization cases, we explore both symmetric and asymmetric flow scenarios. For the symmetric flow case, the optimized flow fields indicate that serpentine flow fields can enhance particle drag variation while accounting for power dissipation. Furthermore, we investigate the effects of Reynolds numbers (<span><math><mrow><mi>R</mi><mi>e</mi><mo>≤</mo><mn>100</mn></mrow></math></span>) and Stokes numbers (<span><math><mrow><mi>St</mi><mo>&lt;</mo><mn>1</mn></mrow></math></span>) on the optimized flow field. The results demonstrate that increasing the Reynolds number results in more bends and greater curvature in the flow field, whereas increasing the Stokes number reduces these features. For the asymmetric flow case, gravity influences particle distribution, leading the serpentine flow paths to adjust their overall orientation to align with these regions of higher particle concentration.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"291 ","pages":"Article 106573"},"PeriodicalIF":2.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474057","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":"Multirate time stepping for aeroelastic simulations of wind turbines using the actuator line model","authors":"Konstantina Ntrelia ,&nbsp;Stefan Vandewalle ,&nbsp;Johan Meyers","doi":"10.1016/j.compfluid.2025.106574","DOIUrl":"10.1016/j.compfluid.2025.106574","url":null,"abstract":"<div><div>In this study we introduce a novel high-order tight coupling methodology based on multirate generalized additive Runge–Kutta schemes, for the aeroelastic simulations of wind turbines. A large eddy simulation framework is coupled to a multibody structural model by utilizing the multirate technique. Turbines are represented by the actuator line model. We explore two different scenarios depending on component partitioning and test them in terms of accuracy and performance. The two coupling approaches are tested in simulations of an NREL 5 MW reference wind turbine inside a uniform inflow. The scheme preserves a high-order accuracy for both coupling methods, while we observe a strong dependency of the numerical solution on the partitioning and the multirate ratio. The implemented multirate schemes demonstrate great potential for achieving algorithmic speed-ups for aeroelastic simulations compared to single-rate methods.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"291 ","pages":"Article 106574"},"PeriodicalIF":2.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465381","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 hybrid diffuse boundary approach for modeling contact-line dynamics within the framework of phase-field lattice Boltzmann method","authors":"Guanlong Guo ,&nbsp;Beichen Ji ,&nbsp;Pei Zhang ,&nbsp;Bin Chen ,&nbsp;S.A. Galindo-Torres","doi":"10.1016/j.compfluid.2025.106575","DOIUrl":"10.1016/j.compfluid.2025.106575","url":null,"abstract":"<div><div>Modeling the dynamics of the contact line among liquid, gas, and solid phases requires enforcing three fundamental boundary conditions on the solid surface: non-penetration, no-slip, and wetting. This study presents a hybrid diffuse boundary approach within the phase-field lattice Boltzmann method to effectively model contact-line dynamics. The proposed method integrates the diffuse domain approach into the Cahn-Hilliard equation to impose the wetting boundary condition, while the smoothed profile method is incorporated into the Navier–Stokes equation to enforce the no-slip and non-penetration conditions. By leveraging the diffuse nature of the boundary/interface, this approach naturally embeds all three boundary conditions directly into the governing equations, eliminating the need for complex numerical treatments at solid boundaries. Compared to the conventional sharp boundary method and the immersed boundary method, the hybrid approach significantly simplifies boundary condition implementation, particularly for complex geometries and moving solid boundaries. Validation tests confirm the accuracy of the method in reproducing prescribed contact angles and ensuring mass conservation. Furthermore, the approach is applied to simulate bubble migration through a pore throat, demonstrating a linear relationship between the Bond number and the contact angle, which delineates distinct passing and trapping behaviors.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"291 ","pages":"Article 106575"},"PeriodicalIF":2.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479051","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}