European Journal of Mechanics B-fluids最新文献

Influence of radiation on the stability of MHD micropolar fluid in a vertical channel 辐射对垂直通道中 MHD 微极性流体稳定性的影响

IF 2.5 3区工程技术

European Journal of Mechanics B-fluids Pub Date : 2024-09-18 DOI: 10.1016/j.euromechflu.2024.09.003

引用次数: 0

The broad study of blade cascade under controlled torsional flutter: Dynamics of the flow and stability analysis 受控扭转扑动下叶片级联的广泛研究：流动动力学和稳定性分析

IF 2.5 3区工程技术

European Journal of Mechanics B-fluids Pub Date : 2024-09-06 DOI: 10.1016/j.euromechflu.2024.08.006

{"title":"The broad study of blade cascade under controlled torsional flutter: Dynamics of the flow and stability analysis","authors":"","doi":"10.1016/j.euromechflu.2024.08.006","DOIUrl":"10.1016/j.euromechflu.2024.08.006","url":null,"abstract":"<div><p>The experimental and numerical investigation of the flow instabilities acting on rigid blades and vice versa was conducted for both compressor and turbine configuration. The blade cascade consisted of five rectangular NACA 0010 blades, with three middle blades capable of performing harmonic motion with one degree of freedom (pitching) using force excitation. The base case (all blades fixed) and excited regime were examined. The influence of various angles of attack, harmonic frequency values, amplitude values, inter-blade phase angles and Reynolds numbers (Re) were tested. The mean flow properties as well as the fluid - structure interaction (FSI) were studied using Particle Image Velocimetry (PIV), Reynolds-averaged Navier-Stokes (RANS) CFD methods and using force measurement. Additionally, two different approaches, namely traveling wave mode (TWM) and aerodynamic influence coefficient (AIC), were adopted to estimate the aeroelastic stability of the blade cascade, and the results were compared. The results show significant aeroelastic coupling between the blades in both compressor and turbine configuration. However, the aerodynamic coupling effect for torsional flutter is more prominent in turbine configuration.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142167856","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

Characterizing nonlinear flow dynamics in hydrodynamic and magnetohydrodynamic regimes through modal decomposition 通过模态分解表征流体动力学和磁流体动力学状态下的非线性流动动力学

IF 2.5 3区工程技术

European Journal of Mechanics B-fluids Pub Date : 2024-09-04 DOI: 10.1016/j.euromechflu.2024.08.008

{"title":"Characterizing nonlinear flow dynamics in hydrodynamic and magnetohydrodynamic regimes through modal decomposition","authors":"","doi":"10.1016/j.euromechflu.2024.08.008","DOIUrl":"10.1016/j.euromechflu.2024.08.008","url":null,"abstract":"<div><p>The study delves into the dynamic behavior of fluid flows in hydrodynamic (HD) and magnetohydrodynamic (MHD) regimes, specifically focusing on the influence of varying magnetic field strengths on vortex shedding around a cylinder. Employing advanced modal decomposition techniques such as Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD), the research unveils the intricate characteristics of these flow fields. In HD scenarios, the flow exhibits complex, periodic patterns with notable vortex shedding, whereas in MHD scenarios, the introduction of magnetic fields gradually transforms the flow into a more stable and streamlined state. The study significantly demonstrates the damping effect of magnetic fields on vortex intensity and oscillations, leading to a uniform flow at higher field strengths. This study leverages DMD to predict future flow dynamics in both HD and MHD regimes around a cylinder. By using snapshots from CFD simulations at Re <span><math><mo>=</mo></math></span> 120, we validate DMD’s predictive capabilities by comparing predicted snapshots with CFD results at corresponding time instants. This approach not only demonstrates DMD’s robustness in capturing complex flow behaviors but also highlights its potential for real-time monitoring and control in industrial applications. The findings provide new insights into the temporal dynamics of MHD flows and open avenues for optimizing flow control strategies in engineering systems.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0997754624001225/pdfft?md5=e0a5d2ec8c67cdd997d5b0229c813672&pid=1-s2.0-S0997754624001225-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impact of viscous dissipation, throughflow and rotation on the thermal convective instability of Jeffrey fluid in a porous medium layer 粘性耗散、贯通流和旋转对多孔介质层中杰弗里流体热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 : 2024-09-04 DOI: 10.1016/j.euromechflu.2024.09.002

{"title":"Impact of viscous dissipation, throughflow and rotation on the thermal convective instability of Jeffrey fluid in a porous medium layer","authors":"","doi":"10.1016/j.euromechflu.2024.09.002","DOIUrl":"10.1016/j.euromechflu.2024.09.002","url":null,"abstract":"<div><p>In this analysis, the collective effects of rotation, viscous dissipation and vertical throughflow on the onset of convective movement in Jeffrey fluid saturated permeable layer is studied. The improved Darcy model is applied to depict the rheological performance of Jeffrey fluid flow in porous medium. The approximate analytical solution with overall error 0.4 % and numerical solution accurate to one decimal place are presented using the Galerkin process. The analysis reveals that the convective motion concentrates in the top layer if it occurred with sufficiently high value of the Darcy–Eckert number. The rotation factor and the Péclet number postponement the onset of convective drive while, the Gebhart number quicken it weakly. In the occurrence of rotation, the Jeffrey factor displays dual impact on the coming of convective movement. The magnitude of the convection cell declines with increasing the rotation factor, the Jeffrey factor and the Péclet number, while it decreases with enhancing the Gebhart number. It is also found that in the lack of rotation, the Jeffrey factor has no impression on the extent of the convective cell, whereas in the nonexistence of the Péclet number, the Gebhart number has no impact on the arrival of convective drive as well as on the magnitude of the convective cells.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142158406","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

Determining pressure from velocity via physics-informed neural network 通过物理信息神经网络根据速度确定压力

IF 2.5 3区工程技术

European Journal of Mechanics B-fluids Pub Date : 2024-09-03 DOI: 10.1016/j.euromechflu.2024.08.007

引用次数: 0

Direct simulation of vortex dynamics of multi-cellular Taylor–Green vortex by pseudo-spectral method 用伪谱分析方法直接模拟多细胞泰勒-格林涡旋动力学

IF 2.5 3区工程技术

European Journal of Mechanics B-fluids Pub Date : 2024-08-17 DOI: 10.1016/j.euromechflu.2024.08.004

{"title":"Direct simulation of vortex dynamics of multi-cellular Taylor–Green vortex by pseudo-spectral method","authors":"","doi":"10.1016/j.euromechflu.2024.08.004","DOIUrl":"10.1016/j.euromechflu.2024.08.004","url":null,"abstract":"<div><p>This study investigates the long-time vorticity dynamics of the multi-cellular configurations of the two-dimensional (2D) Taylor–Green vortex (TGV). The pseudo-spectral method is used to solve the incompressible Navier–Stokes equation to analyze the evolution of TGV arrays. The focus is on understanding vortex interactions leading to vortex filamentation and stripping (forward cascade) during primary instability; merger and reconnection (inverse cascade) among the TGV vortical cells subsequently. Here, consideration of multiple cells avoids imposing symmetries at the smallest periodic length scale, and thereby affecting disturbance growth. The initial condition is taken from the analytic solution of the TGV, and Fourier spectral method is employed to track the interactions of the initial doubly-periodic vortices. The full sequence of evolution from one equilibrium state to another for the TGV is not addressed before, as reported here to fill this gap for multiple TGV cells in both directions. By studying various vortical interactions in the ensemble, here we report the enstrophy and energy spectra for different number of TGV cells. This is crucial in understanding the very long-time evolution process, at post-critical Reynolds numbers for the 2D TGV problem in the same physical domain, (<span><math><mrow><mn>0</mn><mo>≤</mo><mrow><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>)</mo></mrow><mo>≤</mo><mn>4</mn><mi>π</mi></mrow></math></span>) having <span><math><mrow><mo>(</mo><mn>4</mn><mo>×</mo><mn>4</mn><mo>)</mo></mrow></math></span> and <span><math><mrow><mo>(</mo><mn>6</mn><mo>×</mo><mn>6</mn><mo>)</mo></mrow></math></span> cells. Reported results show the evolution of these vortical cells from original configurations to finally a <span><math><mrow><mo>(</mo><mn>1</mn><mo>×</mo><mn>1</mn><mo>)</mo></mrow></math></span> vortical cells — the universal state not demonstrated before.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142012153","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

Review on water-hammer waves mechanical and theoretical foundations 水锤波机械和理论基础综述

IF 2.5 3区工程技术

European Journal of Mechanics B-fluids Pub Date : 2024-08-16 DOI: 10.1016/j.euromechflu.2024.08.001

引用次数: 0

Special issue on experimental investigations of fluid mechanics problems in large ocean research laboratories 大型海洋研究实验室流体力学问题实验研究特刊

IF 2.6 3区工程技术

European Journal of Mechanics B-fluids Pub Date : 2024-08-16 DOI: 10.1016/j.euromechflu.2024.08.005

Y. Li, D.M. Greaves, A.G.L. Borthwick, T.S. van den Bremer

引用次数: 0

Numerical simulation of deep-water wave breaking using RANS: Comparison with experiments 利用 RANS 对深水破浪进行数值模拟：与实验的比较

IF 2.5 3区工程技术

European Journal of Mechanics B-fluids Pub Date : 2024-08-14 DOI: 10.1016/j.euromechflu.2024.08.003

引用次数: 0

Newtonian flow with slip and pressure-drop predictions in hyperbolic confined geometries 双曲约束几何中带有滑移的牛顿流和压降预测

IF 2.5 3区工程技术

European Journal of Mechanics B-fluids Pub Date : 2024-08-13 DOI: 10.1016/j.euromechflu.2024.08.002

{"title":"Newtonian flow with slip and pressure-drop predictions in hyperbolic confined geometries","authors":"","doi":"10.1016/j.euromechflu.2024.08.002","DOIUrl":"10.1016/j.euromechflu.2024.08.002","url":null,"abstract":"<div><p>We study theoretically the steady Newtonian flow in confined and hyperbolic long tubes (symmetric channels and axisymmetric pipes) considering slip along the walls. Using a stream function formulation, and the extended (or high-order) lubrication method in terms of the square of the aspect ratio of the tube, <em>ε</em>, the solution for the stream function is found analytically up to twentieth order in <em>ε</em>. At the classic lubrication limit, i.e. i.e. for a vanishing small aspect ratio, and for perfect slip conditions, the analysis predicts a plug-like velocity profile and a constant strain-rate on the midplane/axis of symmetry of the tube. A constant strain-rate is also predicted for the non-slip case. Furthermore, the high order asymptotic results for the stream function and fluid velocity are post-processed with an acceleration technique to investigate the convergence and accuracy of the solution. The results reveal the existence of a boundary layer at the inlet of the tube, the influence of which diminishes in a very short distance from the entrance. We discuss the effect of the contraction ratio of the tube and the dimensionless slip coefficient on the midplane/centerline and wall (slip) velocities, as well as on the average pressure-drop, required to maintain a constant flow-rate. The acceleration of converge technique on the solution for the pressure-drop revealed a remarkable convergence at a value slightly larger (∼1 %) than the value predicted by the classic lubrication theory. Finally, we comment on the common practice in the literature for approaching the velocity profile with the velocity profile at the classic lubrication limit, and we compare the high-order results for the strain rate at the midplane/centerline with the effective strain rate previously derived in the literature by <em>Housiadas & Beris, J. Rheology, 68(3), 327–339, 2024</em>.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142097293","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