European Journal of Mechanics B-fluids最新文献

{"title":"Experimental study of vortex shedding phenomenon induced by various bluff body geometries for use in vortex flowmeters","authors":"Saeed Farsad ,&nbsp;Seyed Morteza Parpanchi ,&nbsp;Mojtaba Rezaei","doi":"10.1016/j.euromechflu.2025.01.007","DOIUrl":"10.1016/j.euromechflu.2025.01.007","url":null,"abstract":"<div><div>Studying and understanding the vortex-shedding phenomenon in the wake region of bluff bodies is crucial in most fluid systems. This paper uses wind tunnel experiments to evaluate and assess the downstream flow of five bluff body models with various geometric shapes, including triangle, rectangle, square, trapezoid, and T-shape. The aim is to utilize these shapes in flowmeters and angle sensors (as a novel innovation). The velocity field, turbulence intensity, and vortex shedding frequency of the downstream airflow around these models were examined at different flow angles. Results indicate that rectangular and trapezoidal bluff bodies are more suitable for application in flow angle sensors using vortex than other geometries studied. Based on the results, recommend the T-shaped model over other geometries for use in vortex flow meters. Furthermore, the rectangular bluff body at a 107.5° angle provides the most suitable areas for observing vortices and measuring or calibrating hot-wire anemometer probes.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"111 ","pages":"Pages 188-200"},"PeriodicalIF":2.5,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093482","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":"Reconfiguration and drag reduction of flexible beam with point buoyancy in oscillatory flow","authors":"Jixiang Song ,&nbsp;Weimin Chen ,&nbsp;Dingbang Yan ,&nbsp;Shuangxi Guo","doi":"10.1016/j.euromechflu.2025.01.006","DOIUrl":"10.1016/j.euromechflu.2025.01.006","url":null,"abstract":"<div><div>Flexible structures with point buoyancy widely exist in nature and engineering. Under the action of oscillating flow, it usually has a large geometric nonlinear dynamic response. However, the dynamic response and drag reduction of flexible structures with point buoyancy have not been studied. Therefore, the numerical method in this paper investigates the dynamic response and drag reduction of point buoyant flexible structures under oscillatory flow. Firstly, complex spatial curvilinear coordinates establish the dynamic partial differential equations of flexible structures with point buoyancy. Then, the implicit finite-difference time-domain method is used to discretize the partial differential equation in space and time to form an algebraic equation. Finally, the dynamic response and drag reduction of flexible structures under non-buoyancy, uniform buoyancy, and point buoyancy are numerically analyzed. The results show that with the increase of Cauchy number <em>C</em>_<em>Y</em>, the deformation of the flexible structure becomes larger and larger, and a local bending point appears. The dimensionless vibration frequency numbers explain the occurrence of local bending points. Unlike no buoyancy, uniform buoyancy and point buoyancy make the flexible structure smaller and more symmetrical. Uniform buoyancy and point buoyancy can increase the Reconfiguration number <em>R</em>. The greater the buoyancy and buoyancy position, the greater the Reconfiguration number <em>R</em>. The load on the flexible structure under oscillating flow is still less than that on the rigid structure. The Vogel exponent is calculated by fitting the Reconfiguration number <em>R</em>. The drag reduction is directly proportional to the Vogel exponent <em>v</em>, that is, the greater the Vogel exponent <em>v</em>, the greater the drag reduction. When the Cauchy number <em>C</em>_<em>Y</em> is large, the Vogel exponent <em>v</em> of uniform buoyancy and point buoyancy is smaller than that of non-buoyancy. The greater the point buoyancy and buoyancy position, the smaller the deformation of the flexible structure, the greater the Reconfiguration number <em>R</em>, and the greater the Vogel exponent <em>v</em>. When the buoyancy position is small, the influence of point buoyancy on the flexible structure can be ignored.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"111 ","pages":"Pages 162-175"},"PeriodicalIF":2.5,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093484","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":"Dispersion - erosion coupling in landslide","authors":"Bekha Ratna Dangol ,&nbsp;Jeevan Kafle ,&nbsp;Shiva P. Pudasaini","doi":"10.1016/j.euromechflu.2024.12.008","DOIUrl":"10.1016/j.euromechflu.2024.12.008","url":null,"abstract":"<div><div>Non-hydrostatic dispersive models can better describe the landslide motion. Following a dispersive wave equation and a mechanical erosion model for mass flows, here, we develop a novel dynamically coupled dispersion–erosion wave model that combines these two very essential complex processes. The newly developed model for landslide recovers the classical dispersive water waves and dispersive wave equation for landslide as special cases. We present several exact analytical solutions for the coupled dispersion–erosion model. These solutions are constructed for the time and spatial evolution of the flow depth. Solutions reveal that the dispersion and erosion are strongly coupled as they synchronously control the landslide dynamics. The results show that the wave dispersive wave amplifies with the increasing particle concentration, decreasing earth pressure, higher gravitational acceleration, increased slope angle and increased basal friction. The important novel understanding is that the intensity of the dispersive wave increases when erosion and dispersion are coupled. The results indicate the essence of proper selection of the initial and boundary conditions while solving applied and engineering problems associated with the dispersive<!--> <!-->-<!--> <!-->erosive mass transport. This provides the foundation for our understanding of the complex dispersion and erosion processes and their interplay.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"111 ","pages":"Pages 201-214"},"PeriodicalIF":2.5,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093480","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":"Boulder transport under mixed-lubrication friction","authors":"J. DuBerry-Mahon ,&nbsp;J.G. Herterich","doi":"10.1016/j.euromechflu.2025.01.001","DOIUrl":"10.1016/j.euromechflu.2025.01.001","url":null,"abstract":"<div><div>Boulder transport by wave action may exploit thin gaps between the boulder and bedrock platform whereby a lubrication zone reduces the friction coefficient during sliding. We derive an effective mixed-lubrication friction coefficient, depending on boulder speed and the geometry of the lubricated region, and analyse its effect on boulder transport. Mixed lubrication enhances boulder dynamics when moving at a faster speed, the lubricated region is increased, or with fewer separated lubricated regions and smaller boulder aspect ratios. We compare our model against static friction and an empirically-fitted model.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"111 ","pages":"Pages 120-126"},"PeriodicalIF":2.5,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093485","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":"Multiple drops solidifying on a surface with a temperature gradient","authors":"Nang X. Ho ,&nbsp;Thuc V. Yen ,&nbsp;Truong V. Vu","doi":"10.1016/j.euromechflu.2024.12.009","DOIUrl":"10.1016/j.euromechflu.2024.12.009","url":null,"abstract":"<div><div>In many applications, liquid drops perform their solidification on a surface of non-constant cooling temperatures. Such a surface results in various behaviors of drops during the solidification process. Revealing this solidification is the central point of the present study through numerical simulations. Three liquid drops simultaneously start to solidify on a sub-melting-point temperature surface. The surface is coldest on the right side and its temperature linearly increases with respect to the position from the right to the left, resulting in a surface temperature gradient. Thereby, the phase-change interface becomes inclined in all drops with its slope increasing with the surface temperature gradient. The rightmost drop finishes its solidification first while the leftmost drop completes last. With volume expansion, an apex located at the drop top always occurs for all solidified drops. However, unlike drops on a constant temperature surface, the apex of the drops with the surface temperature gradient has a tendency to shift more to the left, resulting in an increase in the apex shift with the surface temperature gradient.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"111 ","pages":"Pages 113-119"},"PeriodicalIF":2.5,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093200","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":"Special issue on experimental investigations of fluid mechanics problems in large ocean research laboratories","authors":"Y. Li,&nbsp;D.M. Greaves,&nbsp;A.G.L. Borthwick,&nbsp;T.S. van den Bremer","doi":"10.1016/j.euromechflu.2024.08.005","DOIUrl":"10.1016/j.euromechflu.2024.08.005","url":null,"abstract":"","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"109 ","pages":"Pages 442-443"},"PeriodicalIF":2.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142203770","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":"Recent advances in the analysis of turbulent superstructures","authors":"Jörg Schumacher ,&nbsp;Wolfgang Schröder","doi":"10.1016/j.euromechflu.2024.07.014","DOIUrl":"10.1016/j.euromechflu.2024.07.014","url":null,"abstract":"","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"109 ","pages":"Pages 440-441"},"PeriodicalIF":2.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141784318","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 horizontal far wake behind a heated or cooled body","authors":"Wilhelm Schneider,&nbsp;Lukáš Bábor","doi":"10.1016/j.euromechflu.2024.12.007","DOIUrl":"10.1016/j.euromechflu.2024.12.007","url":null,"abstract":"<div><div>Buoyancy affects the horizontal wake far downstream of a heated or cooled body in an indirect manner via the hydrostatic pressure perturbation. Plane flow at large Reynolds and Péclet numbers is considered in this paper. The buoyancy effects are characterized by a Richardson number. Both laminar and turbulent flows are investigated to provide asymptotic solutions that are suitable as outflow boundary conditions in computational fluid dynamics.</div><div>Similarity transformations, which are universal, lead to sets of ordinary differential equations. The interaction between the wake and the outer potential flow is taken into account by applying Bernoulli’s equation as a boundary condition. As the thermal energy equation and the boundary conditions for the temperature perturbation are homogeneous, the magnitude of the temperature perturbation is determined by the over-all thermal energy balance.</div><div>The results of the analysis are in remarkable contrast to the classical non-buoyant wake solutions. Driven by the hydrostatic pressure disturbance, the flow does not decay in streamwise direction. The flow is governed by the total heat flow at the body, whereas the effect of the drag force is negligible.</div><div>The set of ordinary differential equations is solved numerically. For laminar flow, two kinds of solutions are found for Richardson numbers below 0.734. One kind of solutions describes a flow field containing a reversed-flow region. For turbulent flow a turbulence model based on the turbulent kinetic energy balance is applied. In addition, the limit of weak buoyancy effects is considered, leading to power laws in terms of the Richardson number.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"111 ","pages":"Pages 250-265"},"PeriodicalIF":2.5,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143093475","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":"An experimental study on the transition of electrohydrodynamic spraying process and regime","authors":"Yin Guan,&nbsp;Yanxiu Sha,&nbsp;Mengduo Wang,&nbsp;Bin He,&nbsp;Jingze Zheng,&nbsp;Zouwei Hu,&nbsp;Yihang Lei","doi":"10.1016/j.euromechflu.2024.12.006","DOIUrl":"10.1016/j.euromechflu.2024.12.006","url":null,"abstract":"<div><div>Electrohydrodynamic (EHD) spraying based manufacturing techniques are remarkably useful for the fabrication of micro/nanoscopic multi-functional devices but also quite complicated owing to their highly changeable spraying behavior and regime. For the propose of gaining more knowledge about different EHD spraying process and regime, this paper carries out an experimental study on EHD spraying of ethanol under a wide range of three key operating parameters: applied voltage (<span><math><mi>Φ</mi></math></span> = 1500– 4000 V), flow rate (<span><math><mi>Q</mi></math></span> = 0.05, 0.1, 0.2, 0.3 mL/min), and nozzle height (<span><math><mi>H</mi></math></span> = 5, 10, 20, 30 mm), while nozzle height was a variable that was barely investigated in previous EHD spraying studies. Six distinct spraying regimes, namely Dripping, Spindle, Atomization, Spindle + Atomization, Whipping, and Oscillation are discovered, whose dependences on these three parameters are demonstrated and explained. Besides, as a significant part of the EHD spraying process, the variations of the spraying period and morphology with these three parameters are also discussed. Moreover, the variations of the spraying regime, spraying frequency, and nondimensionalized Taylor cone length with the electric Bond number and dimensionless flow rate are analyzed, which signifies the close correlation between these dimensionless variables and liquid spraying behaviors. The findings in this work can be used for promoting the understanding of EHD spraying process and achieving more accurate regulation of EHD spraying based manufacturing techniques.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"111 ","pages":"Pages 87-99"},"PeriodicalIF":2.5,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143102374","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":"Euler fluid mechanics solutions to Dirac quantum mechanics equation using multipolar oscillations in spherical geometry","authors":"Álvaro Viúdez","doi":"10.1016/j.euromechflu.2024.12.004","DOIUrl":"10.1016/j.euromechflu.2024.12.004","url":null,"abstract":"<div><div>The multipolar spherical vortex solutions to the Euler equations for Newtonian fluids in background cylindrical flow with swirl satisfy, once their three-dimensional Cartesian velocity components are mapped into the components of a four-component complex vector wave function, the relativistic Dirac equation for a free particle. It is suggested that the vertical component of the intrinsic spin angular momentum of the quantum mechanics particles is the azimuthal wavenumber of the angular phase of the oscillation modes in presence of the background rotation.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"111 ","pages":"Pages 81-86"},"PeriodicalIF":2.5,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143102332","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}