European Journal of Mechanics B-fluids最新文献

{"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":"106 ","pages":"Pages 214-226"},"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}

{"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":"106 ","pages":"Pages 263-279"},"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}

{"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":"106 ","pages":"Pages 181-196"},"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}

{"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":"106 ","pages":"Pages 197-213"},"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}

{"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":"106 ","pages":"Pages 166-180"},"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}

{"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":"&lt;div&gt;&lt;p&gt;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 &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;/ 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 &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; 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 &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;/water hybrid nanofluid. In the case of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;/engine-oil hybrid-nanofluid augmenting &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; 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 &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;mi&gt;S&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; 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":"106 ","pages":"Pages 148-165"},"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}

{"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":"106 ","pages":"Pages 137-147"},"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}

{"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":"106 ","pages":"Pages 130-136"},"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}

{"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":"106 ","pages":"Pages 124-129"},"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}

{"title":"The linear stability of the Kazhikhov–Smagulov model","authors":"C. Jacques,&nbsp;B. Di Pierro,&nbsp;M. Buffat","doi":"10.1016/j.euromechflu.2024.04.001","DOIUrl":"https://doi.org/10.1016/j.euromechflu.2024.04.001","url":null,"abstract":"<div><p>Using the Kazhikhov–Smagulov model, the linear stability of incompressible mixing layers and jets entailing large density variation is addressed analytically. The classical theorems of Squire, Rayleigh and Fjørtoft are extended to variable-density flows. It is shown that the bidimensional configuration is still the most unstable one, but the inflexion point is no longer a necessary condition for instability. Instead, a non trivial condition involving density and velocity gradient is identified. Dispersion relations are obtained for small wavenumbers as well as for piecewise linear base flow profiles. Additionally, an estimation of the threshold wavenumber that stabilises the flow is obtained. It is demonstrated that density variations modify the growth rate of the instability as well as the wavelength associated with the most unstable mode and the unstable wavenumber range. These results are in good agreement with numerical computations. Finally, it is observed that viscous effects are purely stabilising while molecular diffusion does not affect the stability.</p></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"106 ","pages":"Pages 116-123"},"PeriodicalIF":2.6,"publicationDate":"2024-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0997754624000530/pdfft?md5=f482197308eef5090b2c7d7974d37782&pid=1-s2.0-S0997754624000530-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140539194","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}