International Journal of Heat and Fluid Flow最新文献

{"title":"Sparsity-promoting methods for isolating dominant linear amplification mechanisms in wall-bounded flows","authors":"Scott T.M. Dawson,&nbsp;Jaime Prado Zayas,&nbsp;Barbara Lopez-Doriga","doi":"10.1016/j.ijheatfluidflow.2025.109872","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109872","url":null,"abstract":"<div><div>This work proposes a method to identify and isolate the physical mechanisms that are responsible for linear energy amplification in fluid flows. This is achieved by applying a sparsity-promoting methodology to the resolvent form of the governing equations, solving an optimization problem that balances retaining the amplification properties of the original operator with minimizing the number of terms retained in the simplified sparse model. This results in simplified operators that often have very similar pseudospectral properties as the original equations. The method is demonstrated on both incompressible and compressible wall-bounded parallel shear flows, where the results obtained from the proposed method appear to be consistent with known mechanisms and simplifying assumptions, such as the lift-up mechanism, and (for the compressible case) Morkovin’s hypothesis and the strong Reynolds analogy. This provides a framework for the application of this method to problems for which knowledge of pertinent amplification mechanisms is less established.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109872"},"PeriodicalIF":2.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135147","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 performance of inlet/outlet manifold configurations and bottom wall cavities composite in microchannel heat sinks","authors":"Qianjun Mao ,&nbsp;Yue Gu","doi":"10.1016/j.ijheatfluidflow.2025.109894","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109894","url":null,"abstract":"<div><div>High temperature and thermal non-uniformity distribution of electronic devices limited their application and safety. Therefore, three inlet/outlet manifold configurations were proposed: C, I, and Z-type. Additionally, six types of bottom wall cavity structures for manifold microchannel heat sinks were proposed, namely straight bottom wall, square-wavy bottom wall, wavy bottom wall, zigzag bottom wall, right-angled triangle bottom wall in type one, and right-angled triangle bottom wall in type two. The results indicate that the I-type inlet/outlet manifold configuration offers the most uniform flow distribution. Among the six manifold microchannel heat sinks (I-type), the square-wavy bottom wall (I-type) demonstrates the best thermal performance, bottom wall temperature uniformity, and comprehensive temperature uniformity. Additionally, eleven square-wavy bottom wall (I-type) designs were developed for optimization studies in heat transfer. Regarding thermal performance, bottom wall temperature uniformity, and comprehensive temperature uniformity, the optimal square-wavy bottom wall (I-type) exhibits an overall thermal resistance of 0.721, a temperature uniformity factor of 0.424, and a comprehensive temperature uniformity factor of 0.636. Compared to the straight bottom wall (I-type), the optimal square-wavy bottom wall (I-type) reduces the overall thermal resistance, temperature uniformity factor, and comprehensive temperature uniformity factor by 30.3 %, 37.0 %, and 36.4 %, respectively. In addition, the optimal square-wavy bottom wall (I-type) reduces the temperature uniformity factor by 35.1 % at high power (285 W/cm²). This research offers a valuable guideline for designing manifold microchannel heat sinks in high-power electronic devices.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109894"},"PeriodicalIF":2.6,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144123748","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":"Partial sheltering effects on spanwise wake interference of unequal-height tandem finite wall-mounted cylinders","authors":"Ashim Chhetri,&nbsp;Keziah N.D. Hammond,&nbsp;Ebenezer E. Essel","doi":"10.1016/j.ijheatfluidflow.2025.109892","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109892","url":null,"abstract":"<div><div>The effects of partial sheltering on the unsteady flow dynamics of unequal-height tandem finite wall-mounted cylinders fully submerged in a turbulent boundary layer (TBL) were investigated using time-resolved particle image velocimetry. The height ratio of the cylinders was kept constant at <span><math><mrow><mi>h</mi><mo>/</mo><mi>H</mi><mo>=</mo><mn>0.75</mn></mrow></math></span>, where <span><math><mi>h</mi></math></span> and <span><math><mi>H</mi></math></span> are the heights of the upstream cylinder (UC) and downstream cylinder (DC), respectively. The center-to-center spacing between the cylinders was <span><math><mrow><mn>4</mn><mi>d</mi></mrow></math></span>, the Reynolds number based on the cylinder diameter (<span><math><mi>d</mi></math></span>) was <span><math><mrow><mn>5540</mn></mrow></math></span> and the submergence ratio was <span><math><mrow><mi>δ</mi><mo>/</mo><mi>H</mi><mo>=</mo><mn>1.2</mn></mrow></math></span>, where <span><math><mi>δ</mi></math></span> is the TBL thickness. Measurements were also performed for a single cylinder (SC) with a similar aspect ratio (<span><math><mrow><mi>H</mi><mo>/</mo><mi>d</mi><mo>=</mo><mn>7</mn></mrow></math></span>) as the DC. Spatio-temporal characteristics in three streamwise-spanwise planes along the height of the tandem cylinders (TC) and the SC were examined to understand the impact of partial sheltering on the mean wake structure, pumping motion of the reverse flow region, spanwise shear layer growth, and cellular vortex shedding behavior. The results showed that wake interference by the DC enhanced the near-wall pumping motion and integral time scales, while reducing the vortex shedding frequency behind the UC compared to the SC. For the DC, the attachment of the spanwise shear layers from the UC significantly accelerated vortex formation of smaller structures and delayed vortex formation at the unsheltered free end. As a result, the reverse flow region was reduced in the sheltered portion but enhanced near the free end of the DC.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109892"},"PeriodicalIF":2.6,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144115350","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":"Turbulence interactions in a channel flow with spanwise roughness transitions","authors":"Harish Varma ,&nbsp;Vagesh D. Narasimhamurthy ,&nbsp;Amit P. Kesarkar","doi":"10.1016/j.ijheatfluidflow.2025.109886","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109886","url":null,"abstract":"<div><div>A fully developed turbulent channel flow with symmetrically but partially roughened walls is investigated using direct numerical simulation (DNS). The channel walls are roughened with transversely arranged square ribs, where the ribs extend to only half the span-width of the channel, leaving the other half smooth. The three-dimensional (3D) configuration thus produced a unique problem of coflowing rough and smooth turbulent channel flows. An interesting phenomenon of counter rotating pair of secondary roll cells has been observed in the smooth half of the channel. Results are compared with the DNS of turbulent flow at the same friction Reynolds number 400, in a channel with two-dimensional (2D) roughness configuration, where the ribs extend through the entire span. Comparisons were also drawn with DNS of smooth channel flow at the same Reynolds number and it was found that the roll cells on the smooth half not only reduce the bulk flow but also attenuate the turbulence significantly. Although the rough half of the 3D case has a higher bulk velocity, it is more turbulent than the 2D case; this has been attributed to the momentum transfer from the smooth half to the rough half. The anisotropic profiles indicate that the 3D case is more isotropic due to the enhanced mixing caused by the roll cells. Compared to the 2D case, there is an additional vortex shedding in the 3D case, originating from the vertical edges of the ribs at the rough–smooth interface. Statistical turbulent quantities, production and dissipation rates of turbulent kinetic energy, and Fourier analysis are used to arrive at the inferences.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109886"},"PeriodicalIF":2.6,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144115004","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 and experimental study of the hydrothermal response enhancement in mini channel heat sink with double outlet: influence of convergent channels","authors":"Hayder Mohammed Al-Hasani,&nbsp;Basim Freegah,&nbsp;Ammar A. Hussain Al-Taee","doi":"10.1016/j.ijheatfluidflow.2025.109895","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109895","url":null,"abstract":"<div><div>This study delves into the impact of channel convergence on the hydrothermal response and temperature distribution of a serpentine mini-channel heat sink featuring a single inlet and dual outlets. Utilizing ANSYS Fluent 19.R3 software, the research undertakes the creation of three distinct models alongside a reference model, conducting both numerical simulations and experimental investigations to scrutinize this phenomenon comprehensively. Specifically, the study examines the effects of converging channels at varying spacings (2.5 mm, 3 mm, and 3.5 mm) in a laminar flow environment throughout the research duration. The findings reveal a consistent pattern that aligns well with experimental data, showcasing substantial enhancements in reducing the base temperature through the utilization of convergent channels. Noteworthy is the 12 % increase in the Nusselt number at a convergence distance of 2.5 mm, indicating heightened heat transfer efficiency. Moreover, the model featuring the smallest convergence distance exhibits a 3.5 % reduction in thermal resistance compared to its non-converged counterpart. However, despite these advancements, the overall performance evaluation criteria (OPEC) for all models did not witness a significant upsurge owing to the augmented pressure drop.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109895"},"PeriodicalIF":2.6,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099761","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":"Fluid motion prediction from schlieren for ethanol plume velocity measurement","authors":"Shenlin Yang ,&nbsp;Lei Zhao ,&nbsp;Heqing Wang ,&nbsp;Manhou Li ,&nbsp;Wei Xu","doi":"10.1016/j.ijheatfluidflow.2025.109889","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109889","url":null,"abstract":"<div><div>Measuring the velocity distribution of fire plume is particularly challenging. This study proposes a novel optical flow estimation method for schlieren images based on the ethanol pool fires. The physics-informed optical flow framework, termed Fluid Motion Prediction from Schlieren (FMPS) method is introduced, incorporating the Navier-Stokes momentum equations as the constraints. The FMPS method not only captures the kinematic properties of the flow, but also ensures that the estimated flow field conforms to the fundamental laws of fluid mechanics. Results demonstrate that the FMPS method captures more detailed flow features and produces a smoother flow field than the optical flow (OF) method. Compared with OF method, the convergence of FMPS method is relatively fast in the first few iterations. The FMPS method is sensitive to two weighting factors. Meanwhile, the FMPS method produces an optical flow field with the higher accuracy and smaller residuals in localized regions. The FMPS method has a higher fitting degree on the plume flow velocity. The results of <em>V_p/Q</em>^1/5 achieved by OF method are basically consistent with those predicted by McCaffrey model with the relative error in range of −15 % − 40 %. By contrast, the relative error is in the range of −5% − 20 % for FMPS method. For (<em>z_p/Q</em>)^-1/3 &lt; 0.9, the relative error of FMPS method and McCaffrey model decreases to below 10 %, which validates the effectiveness of the FMPS method. The FMPS method demonstrates a good robustness in dealing with fire plume velocity of schlieren images.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109889"},"PeriodicalIF":2.6,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144212731","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":"Turbulent mesoscale convection in the Boussinesq limit and beyond","authors":"Shadab Alam ,&nbsp;Dmitry Krasnov ,&nbsp;Ambrish Pandey ,&nbsp;John Panickacheril John ,&nbsp;Roshan J. Samuel ,&nbsp;Philipp P. Vieweg ,&nbsp;Jörg Schumacher","doi":"10.1016/j.ijheatfluidflow.2025.109856","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109856","url":null,"abstract":"<div><div>Mesoscale convection covers an intermediate scale range between highly fluctuating small-scale turbulence and the global organization of the convection flow. It is often characterized by an order of the convection patterns despite very high Rayleigh numbers and strong turbulent fluctuations. In this article, we review previous and discuss several new aspects of mesoscale convection which have been obtained by three-dimensional direct numerical simulations. These numerical studies are performed in the simplest, yet characteristic configuration of a plane layer that is heated from below and cooled from above. The setup is disentangled from other physical processes which enhance the physical complexity of mesoscale convection in real applications. We cover the role of thermal and mechanical boundary conditions for structure formation, the role of constant rotation of the layer, the impact of the domain shape, and the role of Prandtl number <span><math><mrow><mi>P</mi><mi>r</mi></mrow></math></span>. With respect to the last point, we also obtained results for very low <span><math><mrow><mi>P</mi><mi>r</mi></mrow></math></span> values that arise in astrophysical convection, but are inaccessible in controlled laboratory experiments with liquid metals. In addition to the simplest case of Boussinesq convection, we report studies of non-Boussinesq mesoscale convection in the same configuration. To this end, we investigate effects of compressibility and temperature dependence of material properties. The kinetic energy dissipation rate turns out to remain a central quantity for the turbulent mixing in compressible convection. The different components of energy dissipation rate, their intermittent statistics, their connection to turbulent viscosity, and the resulting multifractal properties are analyzed. Finally, we reflect on what can be learned from the presented studies in idealized configurations for realistic mesoscale convection flows in nature with their increased physical complexity.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109856"},"PeriodicalIF":2.6,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099763","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":"Editorial of Special Issue (SI) on “Large-scale control of wall-bounded flow”","authors":"Ramis Örlü,&nbsp;Philipp Schlatter","doi":"10.1016/j.ijheatfluidflow.2025.109893","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109893","url":null,"abstract":"","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109893"},"PeriodicalIF":2.6,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144212728","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 comprehensive review of loop heat pipe: From fundamental researches to applications","authors":"Qingjie Cui ,&nbsp;Ziyi You ,&nbsp;Yicheng Ni ,&nbsp;Xiaoping Yang ,&nbsp;Yao Zhou ,&nbsp;Jinjia Wei ,&nbsp;Jiping Liu","doi":"10.1016/j.ijheatfluidflow.2025.109880","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109880","url":null,"abstract":"<div><div>With the rapid development of clean energy and artificial intelligence technologies, the thermal management of electronic devices in energy systems, data centers, and new energy vehicles has become a critical challenge. Efficient, compact, and reliable heat dissipation solutions are urgently needed to address the increasing power density and operational demands of these systems. Loop heat pipes (LHP), as a passive phase-change thermal management device, have shown great potential in thermal management of electronic devices both on the ground and in space due to their high efficiency, compactness, and reliability. LHP has attracted widespread global attention, thus, this paper reviews the research progress of loop heat pipes in terms of structural design, heat transfer limit, numerical simulation, and operational stability. The design of loop heat pipes needs to consider specific application environments and work mass selection in order to optimize their thermal performance. It has been shown that the heat transfer efficiency of loop heat pipes can be significantly improved by optimizing the design of the evaporator and condenser, selecting the appropriate component materials, and improving the wick structure. Despite the significant progress, there are still many challenges in the application of loop heat pipes, such as the improvement of heat transfer limits and the suppression of instability. Future research should focus on the application of novel materials, structural optimization, and stability analysis in complex environments, while combining artificial intelligence and big data technologies to achieve more accurate performance prediction and optimal design. This paper provides an important theoretical foundation and development direction for the research and application of loop heat pipes.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109880"},"PeriodicalIF":2.6,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947544","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":"Simulation of the flow and heat transfer characteristics of open-cell metal foams: Two jet impingement heat sinks","authors":"Kun Qian,&nbsp;Jinzhou Sun,&nbsp;Ye Chen,&nbsp;Zhengwei Nie","doi":"10.1016/j.ijheatfluidflow.2025.109890","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109890","url":null,"abstract":"<div><div>Open-cell metal foams, characterized by a high specific surface area and intense flow mixing, provide a promising enhanced heat transfer solution for electronic components. To investigate the internal flow and heat transfer characteristics of metal foams under jet impingement conditions, this paper adopted the local thermal nonequilibrium equation (LTNE) and conducted a simulation study on two heat sink configurations: full-coverage metal foam (MF) and finned metal foam (FMF). The effects of pore density (10 PPI, 20 PPI, 40 PPI, and 60 PPI), jet diameter (10 mm, 20 mm, 40 mm, and a 5 × 9 mm array), and fin structure (coverage and number of fins) on the comprehensive heat transfer performance of metal foam heat sinks were explored. The influence patterns of the pore density, jet diameter, and fin structure on the airflow and heat transfer characteristics inside the heat sink were revealed. The comprehensive heat transfer performance of the two heat sinks was evaluated using the comprehensive performance factor <em>j/f</em>. The research results indicate that, at a jet diameter of 40 mm, the 10 PPI MF heat sink and the FMF heat sink, with a coverage rate of <em>C_s</em> = 0.6 (6 fins), achieved the optimal comprehensive heat transfer performance. The FMF heat sink consistently obtained lower inlet–outlet pressure drops than the MF heat sink. When designing metal foam heat sinks, priority should be given to FMF structures with low pore density and large jet diameters.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"115 ","pages":"Article 109890"},"PeriodicalIF":2.6,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069203","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}