European Journal of Mechanics B-fluids最新文献

{"title":"Statistical and numerical analysis of the flow of a special third grade fluid driven by a shrinking surface","authors":"Rajkumar Saha Chowdhury ,&nbsp;Golam Mortuja Sarkar ,&nbsp;Bikash Sahoo ,&nbsp;Bishal Diyali","doi":"10.1016/j.euromechflu.2025.204275","DOIUrl":"10.1016/j.euromechflu.2025.204275","url":null,"abstract":"<div><div>This paper explores the boundary layer flow and heat transfer characteristics of a special third-grade fluid over a shrinking surface, considering the effects of a magnetic field and thermal radiation. The mathematical formulation of the problem results in nonlinear PDEs, which are transformed into a system of coupled ODEs using Lie group analysis through a set of local similarity variables. The resulting ODEs are then solved numerically using MATLAB’s ‘bvp4c’ solver. Dual solutions are found within a specific range of suction and shrinking parameters. The sheet’s skin friction coefficient and heat transfer rates are analyzed for relevant physical parameters. The results show that the dual solutions bifurcate from a critical point, and no solutions are found beyond this point. A stability analysis is conducted to assess the stability of these two solutions based on the signs of the least eigenvalue. The least eigenvalues are determined numerically, indicating that the upper solution branch (USB) is stable. Thus, the features of the USB can be used to characterize the flow dynamics. Furthermore, multiple linear regression analysis is performed, and we successfully generate the estimated regression equations for the physical quantities for both solutions. The predicted results exhibit strong agreement with the numerical outcomes.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204275"},"PeriodicalIF":2.5,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947387","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":"Comparative hydrodynamic analysis of T and inverse T-shape floating breakwater in oblique wave","authors":"Priya Sharma ,&nbsp;Biman Sarkar ,&nbsp;Soumen De","doi":"10.1016/j.euromechflu.2025.204274","DOIUrl":"10.1016/j.euromechflu.2025.204274","url":null,"abstract":"<div><div>Floating breakwaters hold the potential for a cost-effective solution to offshore protection. This paper conducts a comparative analysis by integrating rectangular horizontal and vertical box configurations to create ”T-shape” and ”inverse T-shape” models as alternative breakwater designs. The engineering and construction of the T-shape and inverse T-shape floating breakwaters represent a significant development in breakwater technology. The study examines the hydrodynamic performance of these breakwaters, focusing on their ability to reduce wave transmission and protect coastal infrastructure. The T and inverse T-shape designs aim to provide flexible and eco-friendly solutions for various coastal environments, particularly those with soft seabeds and moderate wave conditions. This research evaluates their effectiveness in wave reflection, transmission, and hydrodynamic forces, with potential applications in areas such as fishing shelters, port infrastructure, and floating coastal protection systems. The proposed models are formulated using singular integral equations, with the horizontal velocity components as the unknown functions. The Galerkin technique is then adopted to obtain approximate solutions by addressing these singularities. This analytical approach provides an effective validation tool for various numerical approximation methods and then key parameters are studied further which are critical for breakwater designing. Models efficiency are assessed not only through reflection and transmission coefficients but also by analyzing wave forces (horizontal, vertical, and mean drift). The study highlights the importance of breakwater width and draft, and examines how changing wave directions can induce anti-resonance phenomena, affecting breakwater performance.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204274"},"PeriodicalIF":2.5,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143950494","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 blood rheology on haemodynamics and stent-based drug delivery for coronary arteries","authors":"Kimiya Kasaeinia,&nbsp;Rafat Mohammadi,&nbsp;Ali Seyedhosseini","doi":"10.1016/j.euromechflu.2025.204282","DOIUrl":"10.1016/j.euromechflu.2025.204282","url":null,"abstract":"<div><div>Given the significant influence of blood flow characteristics on haemodynamics and the drug transport from stents into arterial tissue, accurately simulating blood flow is essential in numerical studies of arteries, including those involving drug-eluting stents (DES). The complexity of near-wall blood behavior and the numerous rheological models available make blood modeling challenging. In addition, the wide variation in the geometric features of arteries, such as their diameter, can also significantly affect these simulations. On the other hand, the cross-section of the stent strut can also be influential, as it changes the streamlines of blood flow. This work involved comparing various non-Newtonian models with the conventional Newtonian model for coronary arteries using a series of steady-state computational fluid dynamics (CFD) evaluations. The drug transport behavior at different Reynolds numbers and hemodynamic features, like streamlines and wall shear stress (<em>WSS</em>), were analyzed to clarify the influence of these rheological models on both streamlined (semi-circular) and non-streamlined (square) strut cross sections. Furthermore, given that previous research indicated a negligible impact of blood rheology on drug delivery in larger arteries such as renal arteries, the results were compared with outcomes from renal arteries to determine if this holds for coronary arteries with smaller diameters. The results indicate that the smaller the artery, the more significant the role of blood rheology becomes. Specifically, the impact of blood rheology on drug uptake for square strut cross sections was approximately 20 % in coronary arteries, compared to just 5 % in renal arteries. However, the influence of blood rheology in coronary arteries with semi-circular strut profiles was negligible. Regarding haemodynamic features, recirculation lengths were considerably affected by both the Reynolds number and the selected blood rheological model, with these effects being more pronounced in smaller arteries and with square cross sections. Furthermore, the choice of blood viscosity model had a notable effect on the <em>WSS</em> distribution.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204282"},"PeriodicalIF":2.5,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947384","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":"Hydrodynamic stability of Bödewadt flow of a Newtonian fluid over a stationary stretchable disk subject to uniform suction in presence of heat transfer","authors":"Dip Mukherjee ,&nbsp;Burhan Alveroğlu ,&nbsp;Bikash Sahoo","doi":"10.1016/j.euromechflu.2025.204272","DOIUrl":"10.1016/j.euromechflu.2025.204272","url":null,"abstract":"<div><div>This study examines the hydrodynamic stability of an incompressible, Newtonian viscous fluid rotating above a stationary disk within a three-dimensional Bödewadt boundary layer, with a focus on the critical role of stability in practical applications involving rotating machinery and thermal management systems. The investigation explores the combined effects of surface stretching and induced suction on flow behaviour and convective instability characteristics, addressing a key challenge in ensuring stable operational conditions. The lower disk undergoes uniform radial expansion with an induced suction system, and similarity transformations convert the Navier–Stokes equations into a system of coupled ordinary differential equations (ODEs). The mean flow velocity profiles were numerically obtained, and the stability curves were derived through linear stability analysis using a Chebyshev polynomial discretisation approach. Results demonstrate that surface stretching and induced suction significantly enhance stability, particularly in mitigating Type I (cross-flow) instability, a crucial factor in optimising engineering systems reliant on rotating flows. The local stability analysis confirmed the flow stability across the examined parameter range, while the energy analysis the maximum amplification points further supports these findings. By providing a deeper understanding of the flow stabilisation mechanisms, this study offers novel insights with direct implications for industrial and engineering applications requiring precise control of the rotational fluid dynamics.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204272"},"PeriodicalIF":2.5,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143950493","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":"Relativistic electromagnetic solitons in magnetized laser-plasma interactions: A theoretical and parametric study","authors":"H. Bouziane ,&nbsp;K. Annou","doi":"10.1016/j.euromechflu.2025.204269","DOIUrl":"10.1016/j.euromechflu.2025.204269","url":null,"abstract":"<div><div>Electromagnetic solitons created during the interaction of linearly polarized intense laser pulse with a magnetized plasma are investigated. To model the coupled laser-plasma system, fully relativistic hydrodynamic equations are used combined with Maxwell equations. The nonlinear Schrödinger equation is then acquired reflecting the formation of bright or dark solitons depending on the carrier wave frequency, in addition to the expression of the growth rate for modulational instabilities. To add a practical aspect to our study, a parametric analysis was conducted using values that are typical in intense laser-plasma interaction experiments. Our results closely matched the experimental observations, which contributes to the validation of our work.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204269"},"PeriodicalIF":2.5,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143950490","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":"Droplet generation in a flow-focusing microchannel with continuous phase perturbations","authors":"Keqing Lu ,&nbsp;Baokai Huang ,&nbsp;Zhanfeng Chen ,&nbsp;Wen Wang ,&nbsp;He Yang","doi":"10.1016/j.euromechflu.2025.204278","DOIUrl":"10.1016/j.euromechflu.2025.204278","url":null,"abstract":"<div><div>The droplet generation of the droplets with desired size and frequency is of great importance to many applications, e.g., drug delivery, microreactor and digital PCR, etc. Active droplet generation has attracted many attentions, due to the advantages of on-demand, rapid response and high accuracy of the droplet size control. This work numerically investigates droplet formation in a flow-focusing microchannel with the continuous phase perturbation. The perturbations are exerted on the continuous phase at the upstream of the cross junction. The dependence of excitation frequency and magnitude on droplet generation size and frequency are explored in detail. It is found that the droplet generation frequency <em>f</em>_d equals the excitation frequency <em>f</em>_e and its subharmonics. And a step increase of the droplet generation frequency is observed with the increase of the excitation amplitude. Several regimes of droplet generation frequency are found, which is determined by the excitation frequency and amplitude. The physical mechanism behind the excited droplet generation is unveiled. Compared with the excited droplet generation at <em>f</em>_d = <em>f</em>_e, the additional retracting phase and the second squeezing phase are found during the droplet generation process at the regime of <em>f</em>_d = <em>f</em>_e/2. The droplet radius under the excitation can be predicted by the function of the flow rate of the dispersed phase and the excitation frequency <em>R</em>_d=<em>α</em>(<em>Q</em>_d/<em>f</em>_e)^1/3, with the value of <em>α</em> depends on the excitation frequency and amplitude.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204278"},"PeriodicalIF":2.5,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947381","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":"Three-dimensional simulation and analysis of the fluid flow in contraction–expansion array microchannels","authors":"Olga A. Solnyshkina,&nbsp;Aiguzel Z. Bulatova,&nbsp;Nazgul B. Bikkinina","doi":"10.1016/j.euromechflu.2025.204270","DOIUrl":"10.1016/j.euromechflu.2025.204270","url":null,"abstract":"<div><div>The primary objective of this work is to investigate the flow characteristics in contraction–expansion array microchannels with a rectangular cross-section. Flow in channels of this geometry is often found in heat exchangers, as a part of functional elements of microfluidic devices applied in medicine, chemical engineering, etc. To achieve such simulations in three-dimensional case a numerical approach based on the Boundary Element Method accelerated both via the Fast Multipole Method, and heterogeneous computing architecture (multicore CPUs and graphics processors) is utilized. We explore numerically the velocity fields formed in the regions of lateral caverns of rectangular shape. Obtained results have been analyzed in detail for different ratios of cavern length and width, as well as their relative location. In addition, a study of the features of secondary flow formation in the regions of microchannel expansion and their changes depending on the variation of the microchannel height has been carried out. The hydrodynamic resistance and flow regimes in microchannels with different hydraulic diameter of the main part and configuration of side caverns were investigated. The obtained results are expected to be significant for selecting and optimizing contraction–expansion microchannel configuration for a wide range of applications.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204270"},"PeriodicalIF":2.5,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143950491","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":"Optimizing entropy production in bi-diffusive convection within trapezoidal Porous enclosure using radiative trihybrid nanofluids and T-shaped baffle","authors":"Samrat Hansda ,&nbsp;Anirban Chattopadhyay ,&nbsp;Krishno D. Goswami ,&nbsp;Swapan K. Pandit ,&nbsp;Hakan F. Öztop ,&nbsp;Mikhail A. Sheremet","doi":"10.1016/j.euromechflu.2025.204268","DOIUrl":"10.1016/j.euromechflu.2025.204268","url":null,"abstract":"<div><div>This study explores entropy production optimization and thermosolutal transfer enhancement in trapezoidal porous enclosure, commonly used in solar energy systems, electronic cooling, and chemical reactors. The objective is to evaluate the effects of radiative trihybrid nanoliquids on heat and mass transfer in a trapezoidal porous cavity filled with aluminum oxide, copper oxide, and silver nanoparticles dispersed in water, featuring a centrally located T-shaped cold baffle. The lower boundary of the cavity is uniformly heated and soluted, the side boundaries are cooled with low solute concentrations, and the upper boundary is insulated. The governing equations are solved using a Higher Order Compact (HOC) numerical scheme, focusing on parameters such as the Rayleigh number, radiation parameter, buoyancy ratio, and nanoparticle concentration. Results indicate that increasing the Rayleigh number from <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>4</mn></mrow></msup></mrow></math></span> to <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>6</mn></mrow></msup></mrow></math></span> significantly enhances heat and mass transfer rates. Average Nusselt and Sherwood numbers are increased up to 53.04% and 252.49%, respectively, across different configurations. Additionally, raising the radiation parameter values from 1 to 5 boosts the average Nusselt number up to 197.09%, highlighting the dominance of radiative thermal transport. The T-shaped baffle significantly influences flow patterns, reduces entropy generation, and optimizes thermal and solutal transport.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204268"},"PeriodicalIF":2.5,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143950489","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":"Transient slow motions of a composite spherical particle","authors":"Wei C. Lai,&nbsp;Chia L. Chang,&nbsp;Huan J. Keh","doi":"10.1016/j.euromechflu.2025.204276","DOIUrl":"10.1016/j.euromechflu.2025.204276","url":null,"abstract":"<div><div>The transient translation and rotation of a composite spherical particle, consisting of an impermeable hard sphere core and a permeable porous surface layer, in a viscous fluid at low Reynolds number induced by suddenly applied continuous force and torque are analytically studied. By solving the unsteady Stokes and Brinkman equations that respectively govern the fluid flows outside and inside the porous surface layer through the Laplace transform, closed-form formulas of the starting linear and angular velocities of the composite sphere as functions of the relevant parameters are obtained. These velocities increase over time from initial values of zero to their final values, while the linear and angular accelerations of the composite sphere decrease over time, eventually approaching zero. At any elapsed time, these velocities and accelerations increase monotonically and significantly with increasing relative spatial volume and fluid permeability of the porous surface layer of the composite sphere. The transient linear and angular velocities of the composite sphere are generally increasing functions of the porosity of the surface layer, but may decrease slightly with increasing porosity when the particle-to-fluid density ratio is small. The linear and angular accelerations increase with the increase of surface layer porosity in the early stage, no longer change monotonically with its increase in the middle stage, and decrease with its increase in the later stage. The transient linear and angular velocities of the composite sphere decrease with the increase of its relative density, but the linear and angular accelerations only decrease with the increase of the relative density in the early stage and increase with the increase of the relative density in the later stage.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204276"},"PeriodicalIF":2.5,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947380","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":"Damping of ocean waves by a porous disk submerged in a two-layer fluid","authors":"Sunanda Saha ,&nbsp;Swaroop Nandan Bora ,&nbsp;Santu Das","doi":"10.1016/j.euromechflu.2025.204263","DOIUrl":"10.1016/j.euromechflu.2025.204263","url":null,"abstract":"<div><div>The wave interaction with a horizontal porous disk of negligible thickness submerged in either layer of a two-layer fluid is investigated. The solution of the wave scattering problem of the submerged disk is sought analytically by developing an eigenfunction matching approach and using linear potential flow theory. We derive a complex dispersion relation for both scenarios of the disk being placed in either layer, which is required to be solved to get the eigenvalues corresponding to the vertical eigenfunctions. The transition of the eigenvalues is analyzed for the first five solutions, shedding light on the underlying physical process of mode swapping that governs the dissipation mechanism due to porosity. The same algorithm is used to locate the required number of eigenvalues for computation. The effect of different parameters on different physical quantities is analyzed for both scenarios. Known results for a horizontal porous disk submerged in a finite-depth homogeneous fluid are recovered from the present analysis. A critical observation is the reduction in the maximum force amplitude (from 55% to 77%) with increasing values of the porosity parameter (from 2 to 20), demonstrating its enhancement influenced by porosity. In addition, we notice that the positioning of the disk near the free surface or the interface increases the wave force acting on the disk. Hence, the analysis makes it clear that the configuration of the disk plays a key role in maximizing the performance of the disk as a wave absorber.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"113 ","pages":"Article 204263"},"PeriodicalIF":2.5,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947511","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}