International Journal of Heat and Fluid Flow最新文献

{"title":"Probing exponential disjoining pressure in thin films via wettability and sub-atmospheric pressure: An experimental study","authors":"Junhe Wang ,&nbsp;Yongxin Liu ,&nbsp;Tengxiao Ma ,&nbsp;Leping Zhou ,&nbsp;Xiaoze Du","doi":"10.1016/j.ijheatfluidflow.2026.110297","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110297","url":null,"abstract":"<div><div>The stability and transport of nanoscale liquid films under reduced pressure are critical for space thermal management, yet remain poorly understood as classical interfacial theories assume standard atmospheric conditions. This study presents the first systematic experimental investigation of disjoining pressure (<em>P_d</em>) isotherms under low pressure (50–90 kPa) across a broad wettability spectrum (contact angles: 4.18° to 99.11°). Utilizing a novel dual-chamber system that integrates a vacuum-controlled Sheludko cell with multilayer nanoparticle image velocimetry, we simultaneously mapped film thickness and disjoining pressure. It was discovered that reducing pressure induces a fundamental departure from DLVO theory: the equilibrium film thickness increases linearly, while the scaling exponent <em>B</em> in <em>P_d</em> ∼ <em>δ</em>⁻<em>^B</em> grows exponentially to values up to 23.5, which is far exceeding the classical limit of 3 for van der Waals forces. Furthermore, hydrophobic surfaces exhibited a pressure-amplified enhancement of the effective Hamaker constant, correlating with superior evaporation suppression despite minimal film thickness. These findings reveal strong non-classical interfacial thermodynamics in low-pressure environments and establish a new foundation for designing advanced thermal management systems, such as microgravity heat pipes and passive cooling surfaces for planetary habitats.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110297"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170016","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":"Outer-layer similarity from the perspective of uniform momentum zones in turbulent boundary layer over smooth and rough wall","authors":"Zichun Zhang ,&nbsp;Zexin Feng ,&nbsp;Kebing Huo ,&nbsp;Nan Jiang","doi":"10.1016/j.ijheatfluidflow.2026.110292","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110292","url":null,"abstract":"<div><div>The study investigates outer-layer similarity in turbulent boundary layers (TBLs) over smooth and rough walls through the lens of uniform momentum zones (UMZs), measured via two-dimensional particle image velocimetry (PIV) in the streamwise-wall-normal plane at moderate Reynolds numbers. Preliminary analyses of first-order and second-order statistics confirm the broad consistency of outer-layer dynamics across both wall conditions. The turbulent/non-turbulent interface (TNTI) and associated intermittency were examined in both cases, revealing a region of higher intermittency and a thicker boundary layer in the rough-wall case. Despite these differences, the multiple UMZs observed over both surfaces exhibit comparable structural features, consistent with the expectations of outer-layer similarity. A comparative assessment of UMZ geometrical properties—including modal velocity, interface height, and zone thickness—was conducted under two classification schemes. The observed hierarchical arrangement, where thinner near-wall UMZs evolve into thicker outer-layer zones with higher modal velocities, follows a consistent trend for both surfaces. Further insight was obtained by employing conditional averaging with respect to <em>N_UMZ</em>, highlighting both the similarities and deviations in mean velocity, Reynolds stress, dissipation, and production, particularly within the logarithmic region. Quadrant analysis reveals that ejection (Q2) and sweep (Q4) events in rough-wall TBLs exhibit altered scale interactions between small-scale and large-scale motions compared to their smooth-wall counterparts. Two-point conditional correlation analyses stratified by <em>N_UMZ</em> further delineate the spatial organization of coherent structures in both near-wall and outer regions, reinforcing the perspective of outer-layer similarity. Our research advances an innovative structural interpretation of the similarity hypothesis, offering a refined framework for examining universality in wall turbulence.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110292"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170017","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":"Optimizing slot design in pin-fin heat sinks: a numerical approach to lower entropy and pressure drop","authors":"Md Ishtiaque Hossain ,&nbsp;Md Samiul Haider Chowdhury ,&nbsp;Md. Shahjahan Durjoy ,&nbsp;Syed Shaheer Uddin Ahmed ,&nbsp;Istiaq Jamil Siddique","doi":"10.1016/j.ijheatfluidflow.2025.110226","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110226","url":null,"abstract":"<div><div>Minimizing the entropy generation and pressure drop penalty during heat transfer has been a prime concern in the design of heat sinks. One way to mitigate this is to include slots in the pin fin heat sink design, which not only improves the overall heat transfer but also reduces these penalties. Present study numerically investigates the impact of six different slot designs on the conventional pin fin structure, which are venturi, circular cavity, sudden expansion, sudden contraction, linear divergence, and linear convergence. A three-dimensional computational fluid dynamics (CFD) model is used to validate the experimental investigation of a cylindrical pin–fin heat sink, considering four Reynolds numbers ranging from 8,547 to 21,367. Later, the model is utilized to examine different slot-inserted square-shaped fin structures to study the overall performance based on Nusselt number, pressure drop across the heat sink, hydrothermal performance factor (HTPF), thermal resistance, and total entropy generation. Among the six different slots, the venturi slot (VS) outperformed the rest. This configuration reports a 33.6% increase and a 29.03% decrease in HTPF and total entropy generation, respectively. As a follow-up, the VS is applied in the cylindrical pin fin (CPF) to understand the influence of the principal fin design on effective heat transfer.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110226"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923120","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":"Heat transfer characteristics of nonlinearly graded metal foam in thermal storage tank: A novel framework model of BP neural network fused with tactical unit algorithm","authors":"Jiayi Gao ,&nbsp;Xinyu Gao ,&nbsp;Yuanji Li ,&nbsp;Xiaohu Yang ,&nbsp;Ya-Ling He","doi":"10.1016/j.ijheatfluidflow.2026.110236","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110236","url":null,"abstract":"<div><div>Metal foams (MF) are widely used in phase change materials (PCMs) due to their high thermal conductivity, high porosity and large specific surface area. These characteristics jointly improve the thermal performance of PCMs. This study investigates the influence of porosity variation (ranging from 0.85 to 0.96) on the thermal behavior of a phase change thermal storage (PCTS) unit. The research finds that while the reduction of porosity significantly improves the heat storage efficiency, it concurrently reduces the overall storage capacity. Specifically, compared to a porosity of 0.96, a porosity of 0.85 leads to a 71.06% increase in efficiency but is accompanied by a 10.51% decrease in capacity. To further optimize the prediction performance, an improved Tactical Unit Algorithm (ITUA), incorporating elite retention, Lévy flight, and Gaussian mutation strategies, is proposed. Compared to conventional algorithms, ITUA exhibits markedly enhanced optimization performance. Furthermore, ITUA is integrated with a backpropagation artificial neural network (BP-ANN) to develop a model of liquid phase distribution during the melting process. To maintain heat storage capacity while enhancing efficiency, both linear and nonlinear porosity distributions are investigated. At an average porosity of 0.95, energy storage efficiency is increased by 58.46% and 68.95% for linear and nonlinear arrangements, respectively, relative to uniform porosity distribution. The proposed model provides valuable guidance for optimizing MF porosity configuration in PCTS systems.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110236"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923206","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":"Numerical simulation of thermal counterflow in superfluid helium: converging/diverging, hyperbolic/elliptical, and forward/backward steps channels","authors":"Hamid Yousefi,&nbsp;Hossein Afshin","doi":"10.1016/j.ijheatfluidflow.2026.110262","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110262","url":null,"abstract":"<div><div>In this study, the thermal counterflow of superfluid helium is numerically simulated within converging/diverging, hyperbolic/elliptic, and forward/backward step channels —all possessing identical length and volume— in order to gain deeper insight into how channel geometry influences heat transport, thereby supporting improved engineering and design of high-performance heat exchangers. Simulations were performed using the two-fluid model incorporating the Gorter-Mellink mutual friction formulation under varying ratios of maximum to minimum channel height. The newly developed Super-PIMPLE algorithm—previously proposed for coupling the momentum equations of the components with pressure—has also been employed here. Unlike many similar studies, common simplifications have been avoided, and the results have been validated through a four-stage verification process. Key performance indicators, including maximum temperature difference, thermal resistance, effective thermal conductivity, pressure drop, maximum Reynolds number, component velocity difference, and density ratio, were evaluated and compared across the different geometries. The results indicate that, in general, the straight channel yields the lowest thermal gradient (i.e., minimal thermal resistance and highest effective thermal conductivity). When low thermal resistance is prioritized, but a straight channel is not feasible, the elliptic geometry proves to be a more suitable choice. Furthermore, when the cross-section of the heat flux input is not aligned with the isothermal cross-section, it is preferable for the heat flux to be applied at the smaller cross-sectional area; in such cases, step geometries are more advantageous than nozzles/diffusers. The maximum temperature difference in the nozzle geometry is approximately 16.8 times greater, and in the elliptic channel, approximately 3.8 times greater than that of the straight channel. While all non-straight configurations generally exhibit higher pressure drop compared to the straight channel, a notable exception occurs in the hyperbolic geometry. In certain cases, due to the suppression of vortices and oscillatory flows, the pressure drop is reduced by about 64.9% compared to the straight channel. Overall, when minimizing pressure drop is the primary objective, the hyperbolic channel is preferable to the straight geometry. The highest component velocity difference and mutual friction were observed in the converging channel. In nozzle and backward-step geometries, the mean temperature is higher, and the normal fluid fraction is more dominant.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110262"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073598","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":"Multi-objective optimization for maximizing thermohydraulic performance and minimizing entropy generation in finned-tube heat exchangers","authors":"Luan Nguyen Thanh ,&nbsp;An Quoc Hoang ,&nbsp;Le Minh Nhut","doi":"10.1016/j.ijheatfluidflow.2026.110265","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110265","url":null,"abstract":"<div><div>This study addresses the impact of flat tube aspect ratio and inclined tube arrangement on the thermohydraulic properties and entropy generation in a finned-tube heat exchanger under air flow conditions with a low Reynolds number. Furthermore, this study determines the optimal parameters by maximizing thermohydraulic performance and minimizing entropy generation, aiming to provide valuable orientation for the efficient design of finned-tube heat exchangers using flat tubes for application in the air-cooled condensers of refrigeration and air-conditioning systems. The influence of Reynolds number (Re = 125 − 315), tube aspect ratio (e_f = 0.4 − 0.6), and rotation angle (θ = 0 − 30^ο) was considered. Multi-objective optimization was performed using Response Surface Methodology (RSM). The results indicated that the increase in the Reynolds number increased the heat transfer rate (HTR), pressure loss, and entropy generation. Increasing the tube aspect ratio increased pressure loss and entropy generation. The HTR and entropy generation change significantly when the tube arrangement is inclined. However, the variation trend depends on the value of the rotation angle and Reynolds number. The results of multi-objective optimization revealed the optimal parameters of Re = 125.9, e_f = 0.4, and θ = 6.6^ο. These optimal parameters yielded a THP of 1.249, increased the HTC by 11.91 %, and decreased the entropy generation by 2.54 % compared to the reference configuration.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110265"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023352","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 physics-informed neural network coupling framework for predicting heat and mass transfer characteristics of grains","authors":"Hanru Liu ,&nbsp;Tianqi Tang ,&nbsp;Yurong He ,&nbsp;Ming Zhai","doi":"10.1016/j.ijheatfluidflow.2026.110276","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110276","url":null,"abstract":"<div><div>Grain drying is a critical process in agricultural engineering, where optimizing drying efficiency and ensuring product quality depend on accurately understanding the internal temperature and moisture distribution. To obtain the dynamic evolution of internal microscopic information, this study developed a Physics-Informed Neural Network (PINN) coupling framework. By integrating the interaction between temperature and moisture, along with transfer learning, this framework can predict the spatiotemporal evolution of grain temperature and moisture under various drying conditions. The result shows that compared with purely data-driven neural networks (DNN), the PINN coupling framework with added physical constraints achieves lower prediction errors when applied to unknown data. Under the drying condition of 333.15 K, the prediction accuracy of particle temperature and humidity by PINN are improved by 62.4% and 55.3%, respectively, compared with DNN. Furthermore, incorporating transfer learning into the PINN framework significantly improves computational efficiency, enabling the model to adapt more effectively to varying drying conditions. The proposed computational framework offers an innovative approach to explore and predict the dynamic evolution of temperature and moisture in agricultural materials, providing a valuable tool for optimizing drying processes in agriculture and related applications.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110276"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074265","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":"Thermal transport in oscillatory MHD Jeffrey nanofluid flow: Unravelling the impact of nanoparticle geometry and hybrid base fluid ratios in wavy channel","authors":"B. Jaismitha ,&nbsp;J. Sasikumar ,&nbsp;Mustafa Turkyilmazoglu","doi":"10.1016/j.ijheatfluidflow.2026.110291","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110291","url":null,"abstract":"<div><div>Nanofluids play a crucial role in industrial heat exchangers, enhancing thermal efficiency, minimizing energy consumption, and boosting process productivity. However, no prior studies have explored the heat transfer characteristics of oscillatory nanofluid flow involving multiple nanoparticle types and shapes under varying base fluid ratios. The present study examines the MHD oscillatory flow of a Jeffrey nanofluid through an asymmetric wavy channel, incorporating the effects of thermal radiation and a heat source. The study aims to analyse the thermal and mass characteristics of various nanoparticles with three different shape factors in three different ratios of basefluid. The nanofluid consists of a hybrid base mixture of water and ethylene glycol, in varying ratios of 20:80%, 40:60%, and 80:20%, and is infused with three types of nanoparticles: copper (Cu), gold (Au), and alumina (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>). To analyse the impact of nanoparticle shape on heat and mass transfer rates, cylindrical, platelet, and brick-shaped nanoparticles are considered. The governing equations of the dynamic nanofluid systems are transformed into partial differential equations through suitable dimensionless transformations and further converted into ordinary differential equations by taking appropriate solutions for oscillatory-type nanofluid flow. The findings reveal that increasing the ethylene glycol concentration enhances thermal conductivity but reduces mass transfer rates. Among the nanoparticle shapes, platelet structures exhibit superior heat transfer performance compared to cylindrical and brick forms.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110291"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146169970","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 numerical study of a coupled heat transfer process with dual moving domains","authors":"Jaya Joshi,&nbsp;Kalpana Kumari,&nbsp;Rajeev","doi":"10.1016/j.ijheatfluidflow.2026.110284","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110284","url":null,"abstract":"<div><div>The mathematical framework of the lyophilization (Freeze-drying) process belongs to the class of the Stefan problems. The broad applicability of the freeze-drying (FD) process in various industrial and pharmaceutical systems demands a detailed investigation of the process. It is observed that the influence of the size-dependent permeability remains unexplored in the scope of the FD process. This article presents a mathematical formulation of the FD process, incorporating the effects of vapor permeability as a function of the size of the region and molar diffusivity as a function of the molar concentration. The effect of the convective term arising from the moisture distribution of water vapor in the desorbed region is also explored. The mathematical formulation of the considered phase change process includes two continuously moving time-related interfaces. These moving interfaces bring major complexity to the problem. Therefore, a transformed form of Fibonacci wavelets is introduced to tackle the dual moving interfaces. The results show that the solution obtained from the proposed Fibonacci wavelet collocation method (FWCM) is sufficiently equal to the analytical solution. It is identified that the accuracy of the proposed method strengthens with an increasing degree of Fibonacci wavelets. The results demonstrate that the size-related vapor permeability increases the speed of the primary drying phase, whereas it slows down the secondary drying phase. This shows that the size dependent vapor permeability contributes to the higher kinetic energy of the particles in the primary drying region <span><math><mrow><msub><mrow><mi>ζ</mi></mrow><mrow><mn>1</mn></mrow></msub><mrow><mo>(</mo><mi>τ</mi><mo>)</mo></mrow><mo>&lt;</mo><mi>z</mi><mo>&lt;</mo><msub><mrow><mi>ζ</mi></mrow><mrow><mn>2</mn></mrow></msub><mrow><mo>(</mo><mi>τ</mi><mo>)</mo></mrow></mrow></math></span>, whereas the particles in the desorption region <span><math><mrow><mn>0</mn><mo>&lt;</mo><mi>z</mi><mo>&lt;</mo><msub><mrow><mi>ζ</mi></mrow><mrow><mn>1</mn></mrow></msub><mrow><mo>(</mo><mi>τ</mi><mo>)</mo></mrow></mrow></math></span> experience a loss in the phase change energy when the vapor permeability varies with the size of the region.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110284"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073602","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":"Investigation of heat transfer and flow structure around a grooved surface cylinder","authors":"Pooja Thakur ,&nbsp;Yugal Sharma ,&nbsp;Aruna Thakur","doi":"10.1016/j.ijheatfluidflow.2026.110246","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110246","url":null,"abstract":"<div><div>This study investigates the effects of flow and thermal characteristics around a circular cylinder with varying roughness heights, situated in a Bingham plastic fluid. Numerical simulations were performed across the following parameter ranges: 0.1 ≤ Re ≤ 40, 0.7 ≤ Pr ≤ 100, 0 ≤ Bn ≤ 100, and 0 ≤ ε/D ≤ 0.5. The numerical results were validated against existing literature. The analysis includes local and average drag force, streamlines, pressure contours, local and average Nusselt numbers, and isotherms. For ε/D ≤ 0.1, the drag coefficient of the rough-surfaced cylinder exceeds that of the smooth cylinder. Conversely, for ε/D &gt; 0.1, the rough cylinder exhibits a lower drag coefficient than the smooth cylinder. The influence of roughness on the Nusselt number follows a similar pattern. These findings highlight the dependence of conduction and convection heat transfer modes on inertial forces, viscous forces, yield stress effects, and surface texture. A regression technique was employed to develop a correlation for the Nusselt number based on the numerical data, which also reveals discrepancies associated with surface roughness. Additionally, for Bingham plastic fluids, the effect of roughness on drag and the Nusselt number is negligible at low Reynolds numbers. However, for larger roughness and Reynolds numbers (ε/D = 0.1 and Re = 10), significant variations are observed.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110246"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923118","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}