International Journal of Heat and Fluid Flow最新文献

{"title":"The impact of pressure gradient history on flow structures in High Reynolds number rough wall turbulence","authors":"T. Preskett,&nbsp;B. Ganapathisubramani","doi":"10.1016/j.ijheatfluidflow.2025.109942","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109942","url":null,"abstract":"<div><div>High Reynolds number experiments are conducted over a rough wall with strong non-equilibrium pressure gradients. The boundary layer is exposed to different pressure gradient histories via an aerofoil mounted above the boundary layer. Particle image velocity (PIV) allows for the flow development from one chord upstream of the leading edge to one chord downstream of the trailing edge to be captured (3.75 m or <span><math><mrow><mo>≈</mo><mn>22</mn><msub><mrow><mi>δ</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow></math></span>). The freestream speed upstream of the aerofoil is set to 20 m/s, and the resulting <span><math><mrow><mi>R</mi><msub><mrow><mi>e</mi></mrow><mrow><mi>τ</mi></mrow></msub></mrow></math></span> varies from 12900 to 18500. The integral pressure gradient history parameter is seen to have a second-order relationship with the wake strength, <span><math><mi>Π</mi></math></span>. Furthermore, the extent to which the upstream history has to be accounted for is considered. The structures within the flow are examined first through the mean turbulence intensity profiles as well as quadrant analysis. These results show that the effect of flow events on adverse and favourable pressure gradients varies depending on the position within the boundary layer. Some success is achieved in matching the turbulence profiles and flow structure length scales through the integral of the pressure gradient history. The agreement is improved for cases where the local pressure gradient history parameter is also matched.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109942"},"PeriodicalIF":2.6,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704404","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 generalisable data-augmented turbulence model with progressive and interpretable corrections for incompressible wall-bounded flows","authors":"Mario Javier Rincón ,&nbsp;Martino Reclari ,&nbsp;Xiang I.A. Yang ,&nbsp;Mahdi Abkar","doi":"10.1016/j.ijheatfluidflow.2025.109970","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109970","url":null,"abstract":"<div><div>The integration of interpretability and generalisability in data-driven turbulence modelling remains a fundamental challenge for computational fluid dynamics applications. This study yields a generalisable advancement of the <span><math><mi>k</mi></math></span>-<span><math><mi>ω</mi></math></span> Shear Stress Transport (SST) model through a progressive data-augmented framework, combining Bayesian optimisation with physics-guided corrections to improve the predictions of anisotropy-induced secondary flows and flow separation simultaneously. Two interpretable modifications are systematically embedded: (1) a non-linear Reynolds stress anisotropy correction to enhance secondary flow predictions, and (2) an activation-based separation correction in the <span><math><mi>ω</mi></math></span>-equation, regulated by an optimised power-law function to locally adjust turbulent viscosity under adverse pressure gradients. The model is trained using a multi-case computational fluid dynamics-driven <em>a posteriori</em> approach, incorporating periodic hills, duct flow, and channel flow to balance correction efficacy with baseline consistency. Validation across multiple unseen cases – spanning flat-plate boundary layers, high-Reynolds-number periodic hills, and flow over diverse obstacle configurations – demonstrates enhanced accuracy in velocity profiles, recirculation zones, streamwise vorticity, and skin friction distributions while retaining the robustness of the original <span><math><mi>k</mi></math></span>-<span><math><mi>ω</mi></math></span> SST in attached flows. Sparsity-enforced regression ensures reduced parametric complexity, preserving computational efficiency and physical transparency. Results underscore the framework’s ability to generalise across geometries and Reynolds numbers without destabilising corrections, offering a validated framework toward deployable, data-augmented turbulence models for numerical simulations.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109970"},"PeriodicalIF":2.6,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687172","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":"Parametric analysis of a metal foam-based PVT collector coupled with a ventilated room for building heating","authors":"Hani Boussenah ,&nbsp;Abderrahim Bourouis ,&nbsp;Abdullah A. AlZahrani ,&nbsp;Abdeslam Omara ,&nbsp;Samir Djimli","doi":"10.1016/j.ijheatfluidflow.2025.109985","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109985","url":null,"abstract":"<div><div>This study numerically investigates the thermal and dynamic integration between a hybrid photovoltaic-thermal (PVT) solar collector and a ventilated room for efficient renewable heating. To enhance heat transfer, a metal foam layer is embedded beneath the photovoltaic cells. Two distinct domains are considered in this study: laminar flow is assumed in the PVT air channel and simulated using an in-house FORTRAN code based on the finite volume method, while turbulent flow is assumed in the ventilated room and simulated using ANSYS Fluent with the standard k–ε turbulence model. A comprehensive parametric analysis is conducted to evaluate the influence of key parameters, including inlet air velocity, porous medium porosity, Darcy number, and the dimensionless porous layer thickness, on the overall system performance. The results indicate that increasing the porosity from 0.2 to 0.98 reduces electrical efficiency from 12.2 % to 9 %. However, the thermal efficiency shows gains of 67 %, 52 %, 45 %, and 35 % for inlet air velocities of 0.2, 0.3, 0.4, and 0.5 m/s, respectively. At high Darcy numbers (Da ≥ 10⁻³), increasing the porous layer thickness up to 0.8 enhances the system performance, leading to improvements of 47.8 %, 22 %, and 23 % in thermal efficiency, electrical efficiency, and average room temperature, respectively.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109985"},"PeriodicalIF":2.6,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687170","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":"Assessing the methods of extracting attached eddies","authors":"X.X. Li ,&nbsp;L. Fang","doi":"10.1016/j.ijheatfluidflow.2025.109983","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109983","url":null,"abstract":"<div><div>The success of the attached eddy model (AEM) and the search for typical representations of attached eddies call for the development of various methods for extracting attached eddies. However, previous studies have not systematically compared these methods in terms of their statistical wall laws for different physical quantities. In particular, the wall laws for arbitrary moments of the velocity gradient and higher-order velocity derivatives in the logarithmic region, derived in our previous study, have not been checked by using these various methods. In the present study, we focus on three methods, that is, the spectral filtering based on streamwise wavelength (SF), proper orthogonal decomposition (POD), and clustering methodology (CM), and assess their ability of capturing the statistical characteristics predicted by the AEM. It is found that based on two-dimensional instantaneous flow fields, the SF method demonstrates the best performance in capturing the statistical laws of velocity gradients and Hessians, followed by CM, while POD proves inadequate for capturing the scaling laws of velocity gradients and Hessians. Moreover, a parametric analysis is carried out to discuss in detail the specific effects of various parameters in each method on the statistical moments. These results are expected to identify key parameters in these methods and contribute to their improvement, enabling better capture of the statistical laws predicted by the AEM.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109983"},"PeriodicalIF":2.6,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144679945","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":"The influence of nozzle geometries and operating modes on the propulsive performance of continuous unsteady jet","authors":"Xiaofeng He,&nbsp;Yin Li,&nbsp;Wei Yu,&nbsp;Hewen Huang","doi":"10.1016/j.ijheatfluidflow.2025.109986","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109986","url":null,"abstract":"<div><div>In this paper, the effects of the nozzle geometry, formation time and duty cycle on the propulsive performance of continuous unsteady jets were experimentally investigated. Total of seven types of nozzles with different specific cavity shapes and nozzle lip angles were considered, which can be categorized into straight, contracting and expanding nozzles. The output thrust and input power of continuous unsteady jets in different modes of operation are obtained. Based on the experiment data, the power–thrust ratio was used to evaluate the energy conversion efficiency of continuous unsteady jets. The results indicate that the energy saving effect is positively correlated to the mean jet Reynolds number, which the continuous unsteady jet can have high efficiency in the operating mode with small formation time and duty cycle. Furthermore, it is proved that the small nozzle lip angle is conducive to the energy saving of unsteady jets. Analyzed from energy-optimal perspective, among the different nozzles, the hyperbolic nozzle has optimal propulsive performance under the formation time 3.03 and duty cycle 0.4. At this time, the power–thrust ratio is 0.018 watts per newton. The Vitosinski nozzle works under the formation time 2.82 has the widest duty cycle range for high efficiency operation.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109986"},"PeriodicalIF":2.6,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144679946","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":"Research on heat transfer and flow characteristics of latent functionally thermal fluid in circular tubes with embedded fins","authors":"Chenzhen Liu ,&nbsp;Peng Zhao ,&nbsp;Peng Yang ,&nbsp;Peizhao Lyu ,&nbsp;Xinjian Liu ,&nbsp;Zhonghao Rao","doi":"10.1016/j.ijheatfluidflow.2025.109992","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109992","url":null,"abstract":"<div><div>In this paper, an experimental investigation was arranged to study the heat transfer and flow characteristics of latent functionally thermal fluid (LFTF) in circular tubes with different fins (smooth tube, straight finned tube, and cross finned tube). The water-based microencapsulated phase change materials suspension (MPCS) as LFTF was prepared. The effects of microencapsulated phase change materials (MicroEPCM) mass concentration, inlet temperature, heat flux, and circular tube structure on heat transfer and flow performance of MPCS were investigated. The results indicated that the convective heat transfer capacity of MPCS was significantly better than that of water under the same experimental conditions. The optimal inlet temperature and heat flux were 29 °C and 4301.48 W/m², respectively. Among the three types of circular tube structures, the cross-fin tube exhibited the best enhanced heat transfer capability but also resulted in the highest pressure drop loss. When the heat exchange section was a smooth circular tube, the comprehensive evaluation coefficients of 5 wt% MPCS and 10 wt% MPCS were approximately 1.3 and 1.5 times higher than that of water, respectively. This demonstrated that MicroEPCM can enhance the overall heat transfer capability. This study investigated the heat transfer and flow characteristics of LFTF in circular tubes, contributing to the expansion of its practical applications electronic device heat dissipation and battery thermal management.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109992"},"PeriodicalIF":2.6,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670389","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":"Tip gap and coolant mass flux ratio effects on film cooling effectiveness, coefficients of convection, and net heat flux reduction along a transonic turbine airfoil","authors":"Phillip Ligrani ,&nbsp;Hallie Collopy ,&nbsp;Hongzhou Xu ,&nbsp;Michael Fox","doi":"10.1016/j.ijheatfluidflow.2025.109989","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109989","url":null,"abstract":"<div><div>Considered are coefficient of convection, adiabatic effectiveness, and net heat flux reduction characteristics for the extremity end of a transonic turbine airfoil with a squealer rim and coolant films. A cascade that is linear is employed to mount the airfoil along with four additional airfoils. Subsonic conditions are present along the concave side of each considered turbine airfoil, and transonic conditions are present along the convex side of each considered turbine airfoil. Included are spatially-resolved and line-averaged variations of surface heat transfer characteristics, which are given along the concave surface at bigger radial locations and along the extremity end of the turbine airfoil. Film coolant is supplied by two sources which are installed at upstream and downstream positions within the airfoil, such that the ratio of mass flux for the downstream coolant supply BR_d is varied, as the ratio of mass flux for the upstream coolant supply BR_u is approximately constant. Provided for tip gap TG values of 1.20 mm and 2.00 mm are local and line-averaged variations of coefficient of convection ratio, adiabatic film cooling effectiveness, and net heat flux reduction data for specific locations within the recess region, trailing edge region, and upper concave surface region of the airfoil. Associated variations of these surface heat transfer characteristics are related to local levels of turbulent mixing and turbulent shear stress, and to coolant concentrations along and near to the airfoil extremity end surfaces. Resulting coefficient of coefficient ratios, film effectiveness, and net heat flux reduction are often higher for TG = 1.20 mm, relative to the TG = 2.00 mm environment, when compared at the same ratio of mass flux for the downstream coolant supply BRd, and the same airfoil extremity end location.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109989"},"PeriodicalIF":2.6,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662571","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":"Optimization of heat transfer in Al2O3-TiO2/water hybrid nanofluids: A semi-analytical approach","authors":"C.M. Mohana,&nbsp;B. Rushi Kumar","doi":"10.1016/j.ijheatfluidflow.2025.109976","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109976","url":null,"abstract":"<div><div>This paper explores the Al<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>-TiO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>/water hybrid nanofluid flow and heat transfer within a convergent/ divergent channel along with irreversibility analysis. The assumptions taken are the heat source/sink, radiation, viscous dissipation, velocity, and thermal slip effects. The nanoparticle shapes and nanoparticle mixture ratios are also taken into account. Similarity transformations are used to convert the governing partial differential equations into ordinary differential equations, which are solved using the Adomian decomposition technique. As velocity slip increased, velocity profiles increased, while temperature and entropy generation profiles decreased in both the convergent and divergent channels. Temperature and entropy generation increased with thermal slip. Cylindrical and brick-shaped nanoparticles yielded higher heat transfer and entropy generation than spherical shapes. The Al<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>(10%)-TiO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>(90%)/H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O mixture provided superior heat transfer compared to other ratios. Additional analysis using multiple linear regression highlights the influence of various parameters on heat transfer rates and skin friction. In divergent channels, Reynolds number and velocity slip positively affected skin friction, while in convergent channels, Reynolds number had a negative impact and velocity slip had a positive effect. The Eckert number, thermal slip, and heat source parameters positively influenced, whereas the velocity slip parameter negatively influenced, the Nusselt number in both channels. Specifically, the heat transfer rates for a 5% nanoparticle suspension in water improve by 3.61%, 32.23%, and 109.67% in the divergent channel and 3.57%, 30.45%, and 104.60% in the convergent channel for spherical, brick, and cylindrical-shaped nanoparticles, respectively.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109976"},"PeriodicalIF":2.6,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662449","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":"Sensitivity analysis and modeling of thermophysical properties of a hybrid nanofluid by use of different intelligent techniques","authors":"Mohammad Alhuyi Nazari ,&nbsp;Mohammad Hossein Ahmadi ,&nbsp;Mohammad A. Amooie ,&nbsp;Ravinder Kumar ,&nbsp;M.A. Makhanova ,&nbsp;Ualiyeva Zhansulu ,&nbsp;Vojtech Blazek ,&nbsp;Lukas Prokop ,&nbsp;Stanislav Misak","doi":"10.1016/j.ijheatfluidflow.2025.109982","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109982","url":null,"abstract":"<div><div>The thermal conductivity and dynamic viscosity of nanofluids are essential factors in determining heat transfer and fluid flow characteristics. Intelligent methods have demonstrated great effectiveness for the precise estimation and modeling of these properties. The purpose of this study is to model both thermal conductivity and dynamic viscosity of a hybrid nanofluid, TiO₂-SiO₂/water-ethylene glycol, by application of three intelligent approaches namely Group Method of Data Handling (GMDH), Particle Swarm Optimization-Adaptive Neuro Fuzzy Inference System (PSO-ANFIS) and Genetic Algorithm-Adaptive Neuro Fuzzy Inference System (GA-ANFIS). The outcome of the study shows significant precision of the proposed models in estimation of the thermophysical properties. The most accurate models for thermal conductivity and dynamic viscosity are PSO-ANFIS and GMDH, respectively. R² &amp; and Average Absolute Relative Deviation (AARD) for the thermal conductivity and dynamic viscosity of the nanofluids with the most accurate models are 0.9907 &amp; 0.41% and 0.9889 &amp; 2.45%, respectively. Furthermore, sensitivity analysis is conducted on both properties of the nanofluid by considering temperature, concentration, and mixture ratio of the hybrid nanofluids and it is found that for both properties, temperature has the highest effect and is followed by the concentration.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109982"},"PeriodicalIF":2.6,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144632808","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":"Three-dimensional mean flow field around two cubes in tandem","authors":"Barbara L. da Silva,&nbsp;David Sumner,&nbsp;Donald J. Bergstrom","doi":"10.1016/j.ijheatfluidflow.2025.109966","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109966","url":null,"abstract":"<div><div>The mean flow field around two surface-mounted cubes in tandem was investigated through large-eddy simulations at a Reynolds number of Re <span><math><mrow><mo>=</mo><mn>1</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>4</mn></mrow></msup></mrow></math></span> and with a turbulent boundary layer of thickness <span><math><mrow><mi>δ</mi><mo>/</mo><mi>D</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>8</mn></mrow></math></span> at the location of the upstream cube. Center-to-center spacing ratios of <span><math><mrow><mi>L</mi><mo>/</mo><mi>D</mi><mo>=</mo><mn>2</mn></mrow></math></span>, 2.5 and 4 were considered to describe the intermittent reattachment, cavity-locked and synchronized shedding regimes, respectively. The mean flow features were related to the near-surface flow field of the cubes and their drag and normal force coefficients. Although an arch vortex was always present behind the upstream cube, the flow in the gap changed significantly depending on the different flow regimes, affecting the shape, size and strength of the arch vortex. The flow field surrounding the upstream cube did not change significantly with <span><math><mrow><mi>L</mi><mo>/</mo><mi>D</mi></mrow></math></span>, presenting a similar near-surface flow field to an isolated cube. The near-surface flow for the downstream cube changed from a reattachment pattern for <span><math><mrow><mi>L</mi><mo>/</mo><mi>D</mi><mo>=</mo><mn>2</mn></mrow></math></span>, to impingement for <span><math><mrow><mi>L</mi><mo>/</mo><mi>D</mi><mo>=</mo><mn>2</mn><mo>.</mo><mn>5</mn></mrow></math></span>, to flow separation from the leading edges and the appearance of a second horseshoe vortex for <span><math><mrow><mi>L</mi><mo>/</mo><mi>D</mi><mo>=</mo><mn>4</mn></mrow></math></span>. The arch vortex of the downstream cube was uniquely shaped and similar for all <span><math><mrow><mi>L</mi><mo>/</mo><mi>D</mi></mrow></math></span>, due to flow separation from the cube’s rear edges. Base-like streamwise vorticity regions were present in the downstream cube’s wake, which suggest they may be the time-averaged signature of the vortices shed from the cube.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"116 ","pages":"Article 109966"},"PeriodicalIF":2.6,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144632389","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}