European Journal of Mechanics B-fluids最新文献

筛选
英文 中文
A fluid–structure interaction study to analyze the severity of carotid artery stenosis at different locations and its effect on various hemodynamic biomarkers 流体与结构相互作用研究:分析不同位置颈动脉狭窄的严重程度及其对各种血液动力学生物标志物的影响
IF 2.6 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2024-05-07 DOI: 10.1016/j.euromechflu.2024.04.006
Kshitij Shakya, Shubhajit Roy Chowdhury
{"title":"A fluid–structure interaction study to analyze the severity of carotid artery stenosis at different locations and its effect on various hemodynamic biomarkers","authors":"Kshitij Shakya,&nbsp;Shubhajit Roy Chowdhury","doi":"10.1016/j.euromechflu.2024.04.006","DOIUrl":"https://doi.org/10.1016/j.euromechflu.2024.04.006","url":null,"abstract":"<div><p>The study on arterial stenosis has gained rapid interest among researchers in the last decade because of its chronic consequences. Several researchers have tried to investigate stenosis and plaque progression in the carotid artery with different simulation models. In this study, a realistic 3-D geometry of the carotid artery has been used to analyze the effect of varying degrees of stenosis present at different locations of the carotid artery on various hemodynamic parameters. An extensive range of stenosis degrees, starting from a healthy artery(0 %stenosis) to 10%, 30%, 50%, 75%, and 90% stenosis, have been studied. These degrees of stenosis were planted at different locations of the artery grown simultaneously. The whole study was done under the realm of Fluid–Structure Interaction multiphysics. The change in velocity profiles at the areas of stenosis has been found along with the wall shear stress and arterial displacement. The magnitude of velocity and wall shear stress in the case of multiple stenosis locations has been found to be dependent on each other. The presence or absence of one stenosis affects the other, and given the regular and irregular patterns of the velocity profile, wall shear stress, and displacement, their inclusion in blood flow simulation studies having multiple stenoses should be considered.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140914055","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
Particle dynamic behaviors in bubble curtain barriers blocking the diffusion of sediment 阻止沉积物扩散的气泡帘屏障中的颗粒动态行为
IF 2.6 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2024-05-05 DOI: 10.1016/j.euromechflu.2024.04.013
Yuzhu Wang , Jun Wu , Bo Shui , Jian Yang , Wei Wei
{"title":"Particle dynamic behaviors in bubble curtain barriers blocking the diffusion of sediment","authors":"Yuzhu Wang ,&nbsp;Jun Wu ,&nbsp;Bo Shui ,&nbsp;Jian Yang ,&nbsp;Wei Wei","doi":"10.1016/j.euromechflu.2024.04.013","DOIUrl":"https://doi.org/10.1016/j.euromechflu.2024.04.013","url":null,"abstract":"<div><p>Bubble curtains are linear multiphase plumes that are used in industry and engineering to reduce diffusive flows between two zones. The circulating shear flow generated by the bubble plume can effectively create a particle barrier in the water; thus, it is also widely used to suppress the diffusion of suspended particles during dredging operations. To clarify the interaction mechanism between the bubble curtain and suspended particles under pressure-driven flow, experimental studies and numerical simulations were conducted to investigate the particle dynamics in the flow field around the bubble curtain. In this study, we established a formal analogy between a bubble curtain and an air curtain and qualitatively identified four typical distribution zones of the particles in the flow field. Based on the quantitative measurements and theoretical considerations, the optimal operating conditions and the upper limit of effectiveness of the bubble curtain were determined. In addition, the blocking behavior and efficiency of bubble plumes on particles with different <span><math><mrow><mi>R</mi><msub><mrow><mi>e</mi></mrow><mrow><mi>U</mi></mrow></msub></mrow></math></span> and <span><math><mrow><mi>F</mi><msub><mrow><mi>r</mi></mrow><mrow><msub><mrow><mi>U</mi></mrow><mrow><mi>g</mi></mrow></msub></mrow></msub></mrow></math></span>numbers and different particle properties were simulated via the computational fluid dynamics<img>discrete element method (CFD<img>DEM) numerical simulation method.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140901534","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
Exergy destruction within a centrifugal water pump 离心水泵内的能耗破坏
IF 2.6 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2024-05-04 DOI: 10.1016/j.euromechflu.2024.04.007
Jonathan Highgate , Esra Sorguven , Sevil Incir
{"title":"Exergy destruction within a centrifugal water pump","authors":"Jonathan Highgate ,&nbsp;Esra Sorguven ,&nbsp;Sevil Incir","doi":"10.1016/j.euromechflu.2024.04.007","DOIUrl":"10.1016/j.euromechflu.2024.04.007","url":null,"abstract":"<div><p>Understanding the loss generation mechanisms in water pumps is a vital step in decarbonising our built environment, and achieve sustainable cities and communities. In this paper, loss generation mechanisms in a centrifugal pump are quantified by performing exergy analysis with unsteady Reynold Averaged Navier Stokes simulations (uRANS). Exergy analyses are performed at various operational conditions for a commercially available pump and its ideal version that has zero surface roughness. Numerical results are used to derive mathematical expressions to describe exergy destruction rates as functions of normalized flow rates. These expressions provide insight on how and where losses are generated within a centrifugal pump, and how loss generation mechanisms are affected by the flow rate. Results show that 80% of the losses are generated within the impeller, intersection and volute, whereas secondary flows through the deadzone and leakage paths have insignificant contribution to the total losses even though mass flow rate through these paths are considerable. The exergy destruction rate equations derived here, have the potential to replace the semi-empirical estimations of losses in traditional turbomachinery design methodologies and serve as a tool to develop a novel knowledge-based turbomachinery design methodology.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0997754624000591/pdfft?md5=d10d5b2b54a7c4675f03d7d04d324b76&pid=1-s2.0-S0997754624000591-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141031452","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
Effect of particle aspect ratio in targeted drug delivery in abdominal aortic aneurysm 颗粒长宽比对腹主动脉瘤靶向给药的影响
IF 2.6 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2024-05-03 DOI: 10.1016/j.euromechflu.2024.04.009
Sajad Salavatidezfouli , Saeid Barzegar , Armin Sheidani , Arash Hajisharifi , Michele Girfoglio , Giovanni Stabile , Gianluigi Rozza
{"title":"Effect of particle aspect ratio in targeted drug delivery in abdominal aortic aneurysm","authors":"Sajad Salavatidezfouli ,&nbsp;Saeid Barzegar ,&nbsp;Armin Sheidani ,&nbsp;Arash Hajisharifi ,&nbsp;Michele Girfoglio ,&nbsp;Giovanni Stabile ,&nbsp;Gianluigi Rozza","doi":"10.1016/j.euromechflu.2024.04.009","DOIUrl":"https://doi.org/10.1016/j.euromechflu.2024.04.009","url":null,"abstract":"<div><p>Aneurysm is a permanent irreversible bulge in the artery that can occur with higher prevalence among elderly individuals. Although invasive surgical procedures can prevent their development, they come with considerable side effects. Recently, treatments based on targeted drug delivery have gained a lot of attention to suppress aneurysm growth. Numerical simulations have been shown to be of great role in the prediction of blood hemodynamics and vascular wall behaviour in the case of an aneurysm. Moreover, the utilization of high-fidelity approaches such as the Lagrangian frame of reference can address the motion characteristics of microbubble (MB) contrast agents in particulate flows. This study aims to investigate the effect of particle aspect ratio on the adhesion of oblate spheroid particles to the vascular wall. Accordingly, a two-way fluid–structure interaction (FSI) method consisting of a hyperelastic material model for the vessel along with a non-Newtonian, compressible model for blood was employed to simulate an abdominal aortic aneurysm (AAA). Moreover, the ligand–receptor binding concept has been utilized to address the quantification of MBs adhesion. Five sets of aspect ratios ranging from 1 to 9 have been investigated and results indicated that with the increase of the aspect ratio the rate of adhesion decreases. Two drastic changes in the particle number occurred due to the diastolic peak and negative velocity profile, respectively. However, it was concluded that the hydrodynamic of the MBs in terms of velocity and wall distance is rather insensible to the particle shape.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140843111","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
Effect of static compression on near-field tsunami waves: Three-dimensional solution 静态压缩对近场海啸波的影响:三维解决方案
IF 2.6 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2024-05-03 DOI: 10.1016/j.euromechflu.2024.04.008
Santu Das , Michael H. Meylan
{"title":"Effect of static compression on near-field tsunami waves: Three-dimensional solution","authors":"Santu Das ,&nbsp;Michael H. Meylan","doi":"10.1016/j.euromechflu.2024.04.008","DOIUrl":"https://doi.org/10.1016/j.euromechflu.2024.04.008","url":null,"abstract":"<div><p>An analytical solution of three-dimensional surface wave profiles due to arbitrary spatio-temporal disturbance of a circular ocean bottom in a compressible ocean is obtained by incorporating the influence of the static ocean background compression under the assumptions of linearized water wave theory. Time-domain simulations of the surface profile in three dimensions and the pressure distribution within the water column for a circular uniform rise and tilt are shown. The corresponding animation movies depict the temporal evolution of the surface profile and pressure field inside the water column eloquently, which was not shown in earlier literature. The impact of static compression is also discussed through the simulations. A novel analytical expression of the potential function for a generic tilted motion (<span><math><mrow><msup><mrow><mi>r</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>cos</mo><mrow><mo>(</mo><mi>m</mi><mi>θ</mi><mo>)</mo></mrow><mo>,</mo><mspace></mspace><mi>m</mi><mo>∈</mo><mi>Z</mi></mrow></math></span>) of the circular ocean floor is derived. An efficient numerical code is developed to find surface elevation and pressure distribution, implementing the inverse Fourier integral as matrix multiplication. Validation is performed for the specific case of a rising flat ocean floor, showing the oscillations due to acoustic-gravity modes. Initially, a simplified problem of a flat rising ocean bottom is solved using the eigenfunction matching method, which involves finding a particular solution for the nonhomogeneous ocean bottom condition and the solution for its homogeneous counterpart. Solutions are obtained using a newly developed inner product between the depth-dependent functions. Later, a Green function technique is used to incorporate the impact of the arbitrary spatio-temporal motion of the circular portion of the ocean bed. The solution obtained from the eigenfunction matching method is utilized to obtain the analytical form of Green’s function and, eventually, an expression of surface elevation and pressure distribution inside the ocean water column.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140844140","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
Characterization and low-order representation of the vortex meandering motion in upswept afterbody wakes 上掠式余波中涡旋蜿蜒运动的特征和低阶表示法
IF 2.6 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2024-04-24 DOI: 10.1016/j.euromechflu.2024.04.010
Rajesh Ranjan , J.-Ch. Robinet , Datta Gaitonde
{"title":"Characterization and low-order representation of the vortex meandering motion in upswept afterbody wakes","authors":"Rajesh Ranjan ,&nbsp;J.-Ch. Robinet ,&nbsp;Datta Gaitonde","doi":"10.1016/j.euromechflu.2024.04.010","DOIUrl":"10.1016/j.euromechflu.2024.04.010","url":null,"abstract":"<div><p>Vortex meandering is often characterized by seemingly stochastic motions of the vortex core. An elucidation of the underlying mechanisms of core movement aids not only in characterizing the meandering phenomenon but also forms a starting point to guide flow control techniques. This paper investigates the complex motion of longitudinal vortices behind an abstracted cargo aircraft fuselage. In contrast to wingtip vortices that arise in relative isolation, in this case the large aft region upsweep generates a meandering counter-rotating vortex pair that retains its coherence for long distances downstream. High-resolution spatio-temporal datasets obtained from large-eddy simulation of a cylindrical fuselage with longitudinally aligned axis and a sharp-edged base are used for this purpose. The circulation of each vortex in the pair initially increases immediately after formation and asymptotes to a near constant value downstream. Although the time-mean form of the vortices becomes nearly axisymmetric, the transient disorganized motions include time-local regions of opposite vorticity. The complicated meandering motion is decomposed using proper-orthogonal decomposition (POD) modes as primary building blocks. The first two modes constitute a mutually orthogonal <span><math><mrow><mo>|</mo><mi>m</mi><mo>|</mo><mo>=</mo><mn>1</mn></mrow></math></span> elliptic pair, accounting for about 35% of the total energy; individually these modes account for the displacement of vortex cores along straight lines whose slopes coincide with their respective dipole axes. The wake outside of the immediate vicinity of the base displays low-rank behavior, in that the number of modes required to reproduce the flow to a given degree of accuracy diminishes rapidly. Beyond two fuselage (cylinder) diameters downstream, the two leading POD modes can reconstruct the dominant meandering motion and spatial structure in the LES data with less than 15% error using a suitable loss measure.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140778429","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
Thermohydrodynamics of Bödewadt hybrid-nanofluid flow in a horizontal magnetic field 水平磁场中伯德瓦特混合纳米流体流动的热流体力学
IF 2.6 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2024-04-23 DOI: 10.1016/j.euromechflu.2024.04.011
Amit Kumar Pandey, Abhijit Das
{"title":"Thermohydrodynamics of Bödewadt hybrid-nanofluid flow in a horizontal magnetic field","authors":"Amit Kumar Pandey,&nbsp;Abhijit Das","doi":"10.1016/j.euromechflu.2024.04.011","DOIUrl":"10.1016/j.euromechflu.2024.04.011","url":null,"abstract":"<div><p>Since disks, rotating or stationary, are integral in many thermal systems, such as rotating heat exchangers, thermoelectric coolers, solar energy systems, and geothermal plants, this study scrutinizes the thermohydrodynamics of rotating hybrid nanofluid flow over a stretchable disk at rest. Further, the shape of the nanoparticles and the choice of base fluid substantially impact the enhancement of the heat transfer rate in various such thermal systems. Therefore, the present investigation considers engineered colloids made of four distinct (sphere, cylinder, column, lamina) titania and copper nanoparticle shapes in two different base fluids: water and engine-oil. The problem is formulated mathematically in an externally applied horizontal magnetic field and incorporating a non-Fourier heat flux model in the presence of solar radiation. Analogous to the case of the conventional vertical magnetic field, a similarity solution is also possible when magnetic forces act horizontally, both towards and opposite to the direction of rotation. Thus, the governing partial differential equations (PDEs) are first reduced to a set of highly non-linear and coupled ordinary differential equations (ODEs) via similarity transformations. These resulting set of ODEs are then solved numerically using a rapid and efficient spectral quasilinearization method (SQLM). Obtained results show that lamina-shaped <span><math><mrow><mi>T</mi><mi>i</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>−</mo><mi>C</mi><mi>u</mi></mrow></math></span>/ engine-oil hybrid-nanofluid is a better choice than the other shapes of nanoparticle suspension in water. The horizontally applied magnetic field exhibits a stronger influence on the flow and heat transfer characteristics when compared to a vertical magnetic field. Additionally increasing the thermal relaxation parameter <span><math><msub><mrow><mi>α</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span> from 0.1 to 0.35, the Nusselt number boost by 24.44%, 23.41%, 22.54%, and 17.93% for sphere, cylinder, column, and lamina nanoparticles of <span><math><mrow><mi>T</mi><mi>i</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>−</mo><mi>C</mi><mi>u</mi></mrow></math></span>/water hybrid nanofluid. In the case of <span><math><mrow><mi>T</mi><mi>i</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>−</mo><mi>C</mi><mi>u</mi></mrow></math></span>/engine-oil hybrid-nanofluid augmenting <span><math><msub><mrow><mi>α</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span> from 0.1 to 0.35, the Nusselt number rise by 23.95%, 22.83%, 21.82%, and 15.89% for sphere, cylinder, column, and lamina nanoparticles. Based on their increasing <span><math><mrow><mi>N</mi><mi>S</mi></mrow></math></span> and <span><math><mrow><mi>B</mi><mi>e</mi></mrow></math></span> values, the various shapes follow the sequence: lamina ¡ column ¡ cylinder ¡ sphere. Furthermore, entropy generation can be optimized throug","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140780750","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
Slump-flow channel test for evaluating the relations between spreading and rheological parameters of sediment mixtures 用于评估泥沙混合物铺展与流变参数之间关系的坍落流槽试验
IF 2.6 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2024-04-12 DOI: 10.1016/j.euromechflu.2024.04.005
Chyan-Deng Jan , Litan Dey
{"title":"Slump-flow channel test for evaluating the relations between spreading and rheological parameters of sediment mixtures","authors":"Chyan-Deng Jan ,&nbsp;Litan Dey","doi":"10.1016/j.euromechflu.2024.04.005","DOIUrl":"https://doi.org/10.1016/j.euromechflu.2024.04.005","url":null,"abstract":"<div><p>Understanding debris flow phenomena and modeling them effectively requires accurate estimation of their rheological parameters. This study introduces a simple approach defined as the “slump-flow channel test”, which employs a horizontal rectangular channel to evaluate these parameters. The results of slump-flow channel tests indicate that the spreading parameters (spread length, angle of reach, and time to final spread) of sediment mixtures are strongly influenced by their sediment fractions and rheological properties. An empirical analysis of the temporal evolution of the spread length and spread velocity was carried out employing both experimental and simulation results. The numerical simulation of the slump-flow channel tests was performed using the Flow-3D software. Both experimental and simulation results demonstrate that the spreading and the rheological parameters of sediment mixtures exhibit strong correlations and this implies that the rheological parameters of sediment mixtures can be evaluated indirectly using a simple slump-flow channel test.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140644458","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
Tertiary wake mode in flows past elliptic cylinders 流经椭圆圆柱体时的三级唤醒模式
IF 2.6 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2024-04-09 DOI: 10.1016/j.euromechflu.2024.04.004
Deepak Kumar , Bhaskar Kumar
{"title":"Tertiary wake mode in flows past elliptic cylinders","authors":"Deepak Kumar ,&nbsp;Bhaskar Kumar","doi":"10.1016/j.euromechflu.2024.04.004","DOIUrl":"https://doi.org/10.1016/j.euromechflu.2024.04.004","url":null,"abstract":"<div><p>Linear stability analysis of the steady flow past elliptic cylinders of different aspect ratio (<span><math><mrow><mi>A</mi><mi>r</mi></mrow></math></span>) has been conducted for the flow Reynolds number (<span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span>) in the range 30–200. A new unstable mode, which we refer as tertiary wake mode, has been discovered. Two other unstable modes (the primary wake mode and the secondary wake mode), already reported in the literature, are also found. The critical <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span> for the onset of instability of these modes and the corresponding Strouhal number (<span><math><mrow><mi>S</mi><mi>t</mi></mrow></math></span>) have been reported. Modes that have large growth rates tend to come close to the cylinder surface, and the extent to which they spread downstream in the wake is less compared to the weaker modes. The size of the vortical structures in a mode is inversely related to its <span><math><mrow><mi>S</mi><mi>t</mi></mrow></math></span>. The change in the characteristics of these modes with respect to change in <span><math><mrow><mi>A</mi><mi>r</mi></mrow></math></span> and <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span>, as well as their evolution leading to the fully developed flow, has been studied. Selective suppression of the unstable modes is effected using a slip-plate placed on the wake centerline. For <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span> = 150, it is shown that selective suppression of the unstable modes leads to different fully developed unsteady flows.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140543160","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
Exact coordinate-dependent Beltrami coefficient for unsteady axially symmetric viscous vortices 非稳态轴对称粘性涡的精确坐标贝尔特拉米系数
IF 2.6 3区 工程技术
European Journal of Mechanics B-fluids Pub Date : 2024-04-08 DOI: 10.1016/j.euromechflu.2024.04.003
Koichi Takahashi
{"title":"Exact coordinate-dependent Beltrami coefficient for unsteady axially symmetric viscous vortices","authors":"Koichi Takahashi","doi":"10.1016/j.euromechflu.2024.04.003","DOIUrl":"https://doi.org/10.1016/j.euromechflu.2024.04.003","url":null,"abstract":"<div><p>Exact radial-coordinate dependent Beltrami coefficients for unsteady axially symmetric viscous Beltrami vortices under external forces are sought in cylindrical coordinate system. Two types of solutions are presented. One breaks the scaling invariance and decays temporally exponentially. The other one keeps the scaling invariance and asymptotically exhibits a power-law decay. As a byproduct, the exact generalized Beltrami vortex solutions are found and are shown to have lower energy densities.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140539195","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
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信