European Journal of Mechanics B-fluids最新文献

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Intrinsic role of Lagrangian and Stokes drift owed to currents in a stratified three-layered channel with interfacial tensions 拉格朗日漂移和斯托克斯漂移的内在作用归因于具有界面张力的分层三层通道中的电流
IF 2.5 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2025-05-21 DOI: 10.1016/j.euromechflu.2025.204288
Deepali Goyal, S.C. Martha
{"title":"Intrinsic role of Lagrangian and Stokes drift owed to currents in a stratified three-layered channel with interfacial tensions","authors":"Deepali Goyal,&nbsp;S.C. Martha","doi":"10.1016/j.euromechflu.2025.204288","DOIUrl":"10.1016/j.euromechflu.2025.204288","url":null,"abstract":"<div><div>The present study analyses the trajectories of the fluid particles, Stokes drift and Lagrangian drift mechanisms for three-layered internal flow having two interfaces with interfacial tensions. The three-fluid layers are of different densities. A uniform and two dimensional current is flowing in each fluid layer. The pathline equations with first-order solution analysis produces closed trajectories. The trajectories of the fluid particles in the middle layer shows non-monotonic trend as it is subjected to two interfaces and get shorten according to the strength of density stratification and interfacial tensions. The analytical expressions for Stokes drift are found in each layer using small-excursion principle. Based on these expressions, we found that the variation in density causes the Stokes drift displacement to increase more robustly after a critical density ratio for both interfaces. The underlying mechanism of this behaviour is the phase reversal phenomenon which is analysed via phase plane analysis. The trajectories in spatial phase plane are open implying that Stokes drift occurs in each fluid layer. Moreover, the change in density ratio alters the direction of these open trajectories in middle layer at both interfaces, which are shown by drawing their directional fields. The expressions for Lagrangian drift which are dependent on density variations and interfacial tensions are analysed by the ratio of Eulerian return flow to the depth averaged Stokes drift at both interfaces. It is found that weak stratification with higher tension at interface lead to dominance of Eulerian return flow over averaged Stokes drift for middle layer. Also, the effect of these parameters are predominant in the intermediate wave regimes. These observations are essential for understanding the wave characteristics, sediment movement, anticipating the dispersal of contaminants, and modelling climate-related processes like the spread of heat and carbon. Therefore, the study of multilayer systems with Stokes and Lagrangian drift has a considerable potential to further our understanding of marine processes, especially in areas where internal wave action and substantial stratification are present.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204288"},"PeriodicalIF":2.5,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144116454","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}
引用次数: 0
Modeling of tuned liquid dampers with paddles: Hydrodynamic effects and estimation 带桨的调谐液体阻尼器的建模:水动力效应和估计
IF 2.5 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2025-05-16 DOI: 10.1016/j.euromechflu.2025.204305
Andong Wang , Zijie Zhou , Lanfang Zhang , Zhuangning Xie
{"title":"Modeling of tuned liquid dampers with paddles: Hydrodynamic effects and estimation","authors":"Andong Wang ,&nbsp;Zijie Zhou ,&nbsp;Lanfang Zhang ,&nbsp;Zhuangning Xie","doi":"10.1016/j.euromechflu.2025.204305","DOIUrl":"10.1016/j.euromechflu.2025.204305","url":null,"abstract":"<div><div>The hydrodynamic coefficients of internal damping devices, including drag coefficient <em>C</em><sub>d</sub> and inertia coefficient <em>C</em><sub>m</sub>, are crucial parameters affecting the damping and frequency design of the tuned liquid damper (TLD). However, studies on their variation laws are few. This paper presents an approach for estimating paddle hydrodynamic coefficients under harmonic excitation. An equivalent mechanical model (EMM) of the TLD, incorporating <em>C</em><sub>d</sub> and <em>C</em><sub>m</sub> of the paddles, is developed using potential flow theory. The computational fluid dynamics (CFD) method is employed to obtain the TLD’s steady-state response. The discrepancy between the EMM and CFD model responses is then utilized as the objective function and optimized using an improved Archimedes algorithm to determine <em>C</em><sub>d</sub> and <em>C</em><sub>m</sub>. On the basis of the above, a comprehensive parameter analysis is conducted for the TLD with paddles, and the effects of paddle dimension, water depth, and harmonic excitation amplitude on <em>C</em><sub>d</sub> and <em>C</em><sub>m</sub> are examined. Two new dimensionless parameters are introduced based on the Keulegan–Carpenter (KC) number to obtain the empirical formulas for <em>C</em><sub>d</sub> and <em>C</em><sub>m</sub> with superior fitting accuracy. The findings demonstrate that the wave height and base shear force predicted by the EMM generally agree with the CFD results. Compared with the previous constant <em>C</em><sub>m</sub> (<em>C</em><sub>m</sub> = 1), the proposed nonlinear empirical formula for <em>C</em><sub>m</sub> exhibits better accuracy in predicting paddle force and natural sloshing frequency shift generated by the paddles.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204305"},"PeriodicalIF":2.5,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099484","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}
引用次数: 0
Dynamics and scaling of Reynolds shear stress in adverse pressure-gradient flows 逆压力梯度流动中雷诺剪切应力的动力学和标度
IF 2.5 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2025-05-08 DOI: 10.1016/j.euromechflu.2025.204289
T.-W. Lee, J.E. Park
{"title":"Dynamics and scaling of Reynolds shear stress in adverse pressure-gradient flows","authors":"T.-W. Lee,&nbsp;J.E. Park","doi":"10.1016/j.euromechflu.2025.204289","DOIUrl":"10.1016/j.euromechflu.2025.204289","url":null,"abstract":"<div><div>Using a dynamical transport analysis for the turbulence momentum, the Reynolds stress gradient can be expressed as a function of the local momentum flux and force terms for adverse pressure-gradient flows. From the perspective of an observer moving at the local mean velocity, Reynolds stress gradient is seen to represent the lateral transport of streamwise momentum, balanced by the u’<sup>2</sup> transport, pressure and viscous force terms. Data sets (Soria et al., 2020; Gungor et al. [6]; Rkein and Laval [22]) from direct numerical simulations (DNS) are used to validate this method for adverse pressure-gradient boundary layer flows, with a good degree of consistency and agreements. Reynolds shear stress profile, in its full attributes and minor fluctuations, are replicated through the Lagrangian momentum equation. Gradient analysis also leads to scaling at the first- and second-derivative levels, for u’<sup>2</sup>, v’<sup>2</sup> and u’v’. These findings lead to both quantitative prescription and insights on the origin of the Reynolds shear stress structure in adverse pressure-gradient flows.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204289"},"PeriodicalIF":2.5,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143935539","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}
引用次数: 0
The effects of non-uniform internal heating on the convective instability of power-law fluid-saturating-porous layer 非均匀内加热对幂律流体饱和多孔层对流不稳定性的影响
IF 2.5 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2025-05-08 DOI: 10.1016/j.euromechflu.2025.204285
H. Lagziri , H. EL Fakiri
{"title":"The effects of non-uniform internal heating on the convective instability of power-law fluid-saturating-porous layer","authors":"H. Lagziri ,&nbsp;H. EL Fakiri","doi":"10.1016/j.euromechflu.2025.204285","DOIUrl":"10.1016/j.euromechflu.2025.204285","url":null,"abstract":"<div><div>The onset of convection in a porous plate with non-Newtonian saturating fluid is studied using linear stability theory. The horizontal plate is heated internally by a heat source with varying strength along its vertical axis, a situation relevant to certain geophysical applications. Two distinct heating profiles are considered: a linearly antisymmetric distribution in Case <span><math><mi>A</mi></math></span> and a quadratically symmetric distribution in Case <span><math><mi>B</mi></math></span>. The non-Newtonian behavior of the saturating fluid is modeled using the power-law rheology in the Darcy–Forchheimer equation. An inclined throughflow is introduced at an angle <span><math><mi>ξ</mi></math></span> to the horizontal direction. The eigenvalue problem is solved analytically using the Galerkin method of weighted residuals, and the results are verified numerically, via the 4th-order Runge–Kutta technique. The critical values of the internal Rayleigh number <span><math><msub><mrow><mi>R</mi></mrow><mrow><mi>i</mi><mi>c</mi></mrow></msub></math></span>, wave number <span><math><msub><mrow><mi>k</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>, and angular frequency <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> for transverse and longitudinal rolls are affected by Peclet number <span><math><mrow><mi>P</mi><mi>e</mi></mrow></math></span>, form drag coefficient <span><math><mi>G</mi></math></span>, power law index <span><math><mi>n</mi></math></span>, and non-uniformity coefficients <span><math><msub><mrow><mi>q</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>q</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>. The results relative to <span><math><mrow><msub><mrow><mi>q</mi></mrow><mrow><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub><mo>→</mo><mn>0</mn></mrow></math></span> converge well to those relevant to uniform internal heating presented in the literature, serving as a benchmark for the two methods. According to the findings, the effect of the quadratic form drag number <span><math><mi>G</mi></math></span> causes the critical values of shear-thinning fluids to converge to those of Newtonian fluids for both scenarios of stationary and oscillatory convection. This phenomenon is not observed for shear-thickening behavior. In addition, the change in the non-uniformity coefficients <span><math><msub><mrow><mi>q</mi></mrow><mrow><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub></math></span> had a significantly larger impact on the critical values for a shear-thickening fluid than for a shear-thinning one, particularly in Case <span><math><mi>A</mi></math></span>.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204285"},"PeriodicalIF":2.5,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143935540","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}
引用次数: 0
Migration of a porous spherical particle in the presence of a non-deformable interface 在不可变形界面的存在下多孔球形粒子的迁移
IF 2.5 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2025-05-06 DOI: 10.1016/j.euromechflu.2025.204277
M.S. Faltas , H.H. Sherief , E.I. Saad , A.S. Aamer
{"title":"Migration of a porous spherical particle in the presence of a non-deformable interface","authors":"M.S. Faltas ,&nbsp;H.H. Sherief ,&nbsp;E.I. Saad ,&nbsp;A.S. Aamer","doi":"10.1016/j.euromechflu.2025.204277","DOIUrl":"10.1016/j.euromechflu.2025.204277","url":null,"abstract":"<div><div>Semi-analytical solutions are obtained for a porous spherical particle moving in the presence of an interface separating two immiscible Newtonian fluids. The motion of the particle is considered for the following two cases: (a) quasi-steady translation perpendicular to the interface and (b) steady rotation about a diameter perpendicular to the interface. The porous medium within the particle is governed by the Brinkman equation with a tangential stress jump condition. The Capillary number is assumed to be small, which leads to negligible interface deformation. Using both cylindrical and spherical coordinates, general solutions for the Newtonian and Brinkman regions are constructed from basic solutions. Conditions are first satisfied at the bounding interface, followed by the application of the Fourier–Bessel transforms; then comes the application of the boundary conditions at the surface of the porous particle, which is handled by a collocation technique. The aim of this paper is to study and determine the effect of the bounding interface and the permeability of the Brinkman region on the drag force and torque acting on the porous particle. The drag force and torque coefficients are calculated with good convergence as functions of the dimensionless clearance distance between the porous particle and the bounding interface for the entire range of the dimensionless hydraulic permeability of the Brinkman medium, the stress jump factor, and the viscosity ratio between the fluid containing the particle and the fluid below the interface. Our collocation results are in good agreement with the available solutions in the literature for the limiting cases. The present study has potential applications in the fields of biomedical and industrial processes, such as the biophysics of membranes and porous agglomerates.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204277"},"PeriodicalIF":2.5,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143927525","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}
引用次数: 0
Experimental and numerical optimization of orifice entrance conical geometry in a multi-hole plate to reduce the plate pressure loss 多孔板孔口圆锥形几何形状的实验与数值优化以降低板的压力损失
IF 2.5 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2025-05-05 DOI: 10.1016/j.euromechflu.2025.204287
Hasan Düz
{"title":"Experimental and numerical optimization of orifice entrance conical geometry in a multi-hole plate to reduce the plate pressure loss","authors":"Hasan Düz","doi":"10.1016/j.euromechflu.2025.204287","DOIUrl":"10.1016/j.euromechflu.2025.204287","url":null,"abstract":"<div><div>Multi-hole plates are extensively used in various flow systems in order to overcome the distorted flow issues or to achieve high pressure drops, however, they cause significant pressure losses that lead to high pump power consumption. In order to make an improvement, the present study proposed conical-edged orifice entrance for multi-hole plate that can be through its optimization to minimize the pressure loss caused by its sharp square-edged orifices. In this regard, conical-edged multi-hole plates, each the same in the distribution of eight holes and their diameters but distinguished by conical angle (<em>θ</em>) and relative conical height (<em>h / t</em>), were optimized experimentally and numerically with water flows inside a circular test pipe by varying pipe Reynolds number (368 ≤ <em>Re</em> ≤ 33909). The results analyzed graphically showed an optimum conical angle about 20 degrees at the point of minimum pressure loss as a regardless of <em>Re</em> and <em>h / t</em>, in a capability reduced the pressure loss caused by sharp square-edged multi-hole plate by 23 −53 % and with an improvement steeply raised with <em>Re</em>. A formula predicting pressure loss as a function of <em>Re</em> and <em>h / t</em> was developed for 15, 20 and 30 degree conical angles. Published empirical formulas were utilized also to validate the obtained results both experimentally and numerically.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204287"},"PeriodicalIF":2.5,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143942294","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}
引用次数: 0
Boundary element analysis of liquid sloshing in a three-dimensional liquid tank with porous structure 三维多孔结构液槽内液体晃动的边界元分析
IF 2.5 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2025-05-02 DOI: 10.1016/j.euromechflu.2025.204286
Ke Zhao , Jun Liu , Quansheng Zang , Lei Gan , Jie Ren , Zhi Liu , Lei Xiong , Hao Gu , Wenbin Ye
{"title":"Boundary element analysis of liquid sloshing in a three-dimensional liquid tank with porous structure","authors":"Ke Zhao ,&nbsp;Jun Liu ,&nbsp;Quansheng Zang ,&nbsp;Lei Gan ,&nbsp;Jie Ren ,&nbsp;Zhi Liu ,&nbsp;Lei Xiong ,&nbsp;Hao Gu ,&nbsp;Wenbin Ye","doi":"10.1016/j.euromechflu.2025.204286","DOIUrl":"10.1016/j.euromechflu.2025.204286","url":null,"abstract":"<div><div>This paper investigates the liquid sloshing problem in three-dimensional tanks with a porous structure using the boundary element method (BEM). Based on linear potential flow theory and the Bernoulli equation, we present a discretization strategy along with a detailed derivation of the boundary element integral equation for the three-dimensional liquid sloshing problem. The problem can be transformed into a two-dimensional framework by employing boundary integral equations defined on the boundary as the governing equations. These equations are subsequently converted into algebraic equations through the interpolation of boundary elements, which significantly reduces the number of required nodes. The boundary conditions on both sides of the porous structure are established in accordance with Darcy's law and the Bernoulli equation. The study examines the sloshing behavior both in cubic, cylinder and annular cylinder liquid tanks, incorporating a porous baffle to mitigate the sloshing phenomenon. Numerical results demonstrate the accuracy and reliability of the proposed model, indicating that modifications to the length, width, shape, and other geometric dimensions of the porous baffle significantly influence the sloshing response of the liquid within the tank. Generally, a higher installation position of the transverse porous baffle within liquid tanks of varying shapes enhances the suppression of liquid sloshing, while the configuration of the vertical baffle is contingent upon the specific shape of the tank. Additionally, as the porous-effect parameter increases, the peak value of the responses initially decreases before subsequently increasing. In addition, the limitations of linear potential flow theory were analyzed, and future research directions were suggested.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204286"},"PeriodicalIF":2.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143917305","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}
引用次数: 0
Study of heat transfer in a rotating weakly electrically conducting Newtonian fluid: Primary and Küppers-Lortz regimes 旋转弱导电性牛顿流体的传热研究:初级和k<e:2> -洛尔兹体系
IF 2.5 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2025-04-30 DOI: 10.1016/j.euromechflu.2025.204283
B. Sirisha Reddy, S. Pranesh, P.G. Siddheshwar
{"title":"Study of heat transfer in a rotating weakly electrically conducting Newtonian fluid: Primary and Küppers-Lortz regimes","authors":"B. Sirisha Reddy,&nbsp;S. Pranesh,&nbsp;P.G. Siddheshwar","doi":"10.1016/j.euromechflu.2025.204283","DOIUrl":"10.1016/j.euromechflu.2025.204283","url":null,"abstract":"<div><div>In this paper, we study the primary and secondary (Küppers-Lortz) instabilities of rotating Rayleigh–Bénard convection for a weakly electrically conducting Newtonian fluid with idealistic boundaries. The critical Rayleigh number is obtained for each instability. Fourth-order and ninth-order Lorenz model are derived using the truncated Fourier-Galerkin expansion and the onset of primary and secondary instabilities is studied. Using a non-linear analysis, we derive the expression for the Nusselt number for both primary and secondary instabilities. The analysis reveals that the heat transfer in the case of primary instability is an over-prediction when compared with that of the secondary instability. An increase in the strength of the magnetic field is to delay the onset of primary and secondary instabilities and decrease the heat transfer. These insights advance the understanding of magnetohydrodynamic stability in rotating convective systems and have implications for geophysical and astrophysical fluid dynamics.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204283"},"PeriodicalIF":2.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143900256","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}
引用次数: 0
Compressible magnetohydrodynamic flat plate boundary layer flow with slightly rarefied effects 具有轻微稀薄效应的可压缩磁流体动力平板边界层流动
IF 2.5 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2025-04-26 DOI: 10.1016/j.euromechflu.2025.204281
Shunhao Peng , Tianyi Peng , Yongliang Feng , Xiaojing Zheng
{"title":"Compressible magnetohydrodynamic flat plate boundary layer flow with slightly rarefied effects","authors":"Shunhao Peng ,&nbsp;Tianyi Peng ,&nbsp;Yongliang Feng ,&nbsp;Xiaojing Zheng","doi":"10.1016/j.euromechflu.2025.204281","DOIUrl":"10.1016/j.euromechflu.2025.204281","url":null,"abstract":"<div><div>In this work, the influence of the applied electromagnetic field and rarefied gas effect on the compressible laminar boundary layer flow is investigated using locally self-similar solutions and Computational Fluid Dynamics (CFD) simulations. Firstly, the locally self-similar solutions under a uniform electromagnetic field with load factor <span><math><mrow><mi>K</mi><mo>=</mo><mn>1</mn></mrow></math></span> are conducted to analyze the flow characteristics of the rarefied magnetohydrodynamic (MHD) boundary layer. Subsequently, CFD simulations with various load factors are performed to study the influence of the electromagnetic field on slip effects. Finally, the induced magnetic field under a dipole electromagnetic field is calculated with the Biot–Savart law to assess the validity of the low-magnetic-Reynolds-number assumption for rarefied MHD flow. The results demonstrate that slip effects under the applied electromagnetic field are weakened at <span><math><mrow><mi>K</mi><mo>=</mo><mn>0</mn></mrow></math></span> but significantly enhanced at <span><math><mrow><mi>K</mi><mo>=</mo><mn>1</mn></mrow></math></span> and <span><math><mrow><mi>K</mi><mo>=</mo><mn>2</mn></mrow></math></span> due to changes in boundary layer profiles. Additionally, the induced magnetic field is found to be strongly affected by the load factor and the magnetic Reynolds number but almost independent of the Knudsen number. This suggests that the criterion for low-magnetic-Reynolds-number assumption in continuum flows can be directly applied to rarefied MHD flows.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204281"},"PeriodicalIF":2.5,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904011","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}
引用次数: 0
Numerical study of Hall currents induced by radial magnetic fields on free convective flow through asymmetrically heated/cooled vertical annuli 径向磁场对非对称加热/冷却垂直环空自由对流产生霍尔电流的数值研究
IF 2.5 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2025-04-25 DOI: 10.1016/j.euromechflu.2025.204279
Vijay Kumar Sukariya, Anurag, Anand Kumar
{"title":"Numerical study of Hall currents induced by radial magnetic fields on free convective flow through asymmetrically heated/cooled vertical annuli","authors":"Vijay Kumar Sukariya,&nbsp;Anurag,&nbsp;Anand Kumar","doi":"10.1016/j.euromechflu.2025.204279","DOIUrl":"10.1016/j.euromechflu.2025.204279","url":null,"abstract":"<div><div>The Hall effect, discovered over a century ago, continues to be significant and increasingly relevant across various sectors. Its applications range from technological advancements to medical technology, where Hall current phenomena are essential for optimizing performance and driving innovation. The ongoing integration of Hall effects into contemporary systems highlights its enduring value in both research and industry. In continuation of this enduring relevance, we studied the influence of Hall currents in vertical concentric cylinders subjected to a radial magnetic field, with the outer cylinder asymmetrically heated or cooled. The governing system of partial differential equations was solved using the Crank–Nicolson method to analyze fluid temperature, velocity, and skin friction under the influence of various dimensionless parameters, with results presented through both graphical and tabular perspectives. The outputs are verified with different numerical methods and validated against existing literature to ensure the accuracy and reliability of the results. The study reveals that the Hall current induced by the radial magnetic field is approximately 15% stronger than that generated by a conventional magnetic field at <span><math><mrow><mi>r</mi><mo>=</mo><mn>1</mn><mo>.</mo><mn>5</mn></mrow></math></span>. However, the radial magnetic field has a lesser impact in reducing fluid flow compared to the conventional magnetic field, due to its directional dependence on the radial axis. Furthermore, when the buoyancy force parameter is in the range <span><math><mrow><mn>0</mn><mo>≤</mo><mi>R</mi><mo>&lt;</mo><mn>1</mn></mrow></math></span>, the maximum velocity is concentrated near the inner cylinder and decreases towards the outer cylinder, whereas at <span><math><mrow><mi>R</mi><mo>=</mo><mn>1</mn></mrow></math></span>, the maximum velocity shifts towards the central region and takes a parabolic shape.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204279"},"PeriodicalIF":2.5,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873946","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}
引用次数: 0
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