European Journal of Mechanics B-fluids最新文献

{"title":"The effects of different synthetic eddy disturbances on boundary layer transition in high speed flow","authors":"Shuo Feng,&nbsp;Bofu Wang,&nbsp;Tienchong Chang,&nbsp;Quan Zhou","doi":"10.1016/j.euromechflu.2025.204318","DOIUrl":"10.1016/j.euromechflu.2025.204318","url":null,"abstract":"<div><div>This study employs Large Eddy Simulation (LES) to investigate the impact of initial synthetic eddy disturbances on the nonlinear transition process and turbulence characteristics within a boundary layer at a Mach number of 2.25. This study examines the influence of synthesized eddies with varying rotational directions, turbulence intensities, and spatial sizes on the boundary layer transition process and the characteristics of the post-transition flow field. Significant differences are observed in the transition starting position, high friction resistance region, and downstream turbulent pulsations among eddies with distinct parameters. Eddies with different rotational directions initiate transition at the same position and conclude at the same location. In contrast, the beginning of the transition of synthetic eddies with lower turbulence intensity is significantly delayed, although the length of the transition interval remains approximately equal across different turbulence intensities. Large-scale eddies can effectively induce rapid boundary layer transition but also lead to pronounced local peaks in surface friction and heat flux. This characteristic is detrimental to thermal protection in regions where heat flux is prone to overshoot.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204318"},"PeriodicalIF":2.5,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570401","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":"Numerical analysis of collision impact and sound noise in axial flow check valve","authors":"Guang Zhang ,&nbsp;Jia Chen Guan ,&nbsp;Run Hua Hu ,&nbsp;Jun Yu Tao ,&nbsp;De Sheng Chen ,&nbsp;Zhe Lin","doi":"10.1016/j.euromechflu.2025.204323","DOIUrl":"10.1016/j.euromechflu.2025.204323","url":null,"abstract":"<div><div>As a key fluid control device, axial check valves play a vital role in industrial systems, but they may encounter a series of problems during their operation, including noise and collision failure. Collision may lead to wear and fatigue of the valve components, which in turn affects their normal operation. Noise not only causes environmental pollution but also may adversely affect the staff and the surrounding environment. In this paper, based on the dynamic mesh and fluid-solid coupling of the valve closing process flow field and structural deformation of the three-dimensional numerical simulation study, we analyze the differential pressure on the valve collision impact characteristics and the valve internal flow under the influence of the noise law. The results show that the larger the pressure difference between the inlet and outlet, the faster the valve closes, the larger the impact generated by the collision, and the larger the deformation generated by the valve flap and valve seat. The axial flow check valve gradually closes when the flow path is narrowed, resulting in a higher flow field noise level. Sound pressure greater than 100 dB in the frequency range is mainly distributed at 200 Hz or less.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204323"},"PeriodicalIF":2.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522142","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":"Rheo-soluto-dynamics of confined Stokes-second-problem type electro-magneto-kinetic flows","authors":"Neeladri Sekhar Bera,&nbsp;Purbarun Dhar","doi":"10.1016/j.euromechflu.2025.204320","DOIUrl":"10.1016/j.euromechflu.2025.204320","url":null,"abstract":"<div><div>This study presents an analytical investigation of electro-magneto-hydrodynamic (EMHD) flow and solute transport in a parallel-plate microchannel filled with a viscoelastic (Jeffrey) fluid. The system mimics a confined Stokes’ second problem, with harmonically oscillating walls and externally applied magnetic and electric fields. The microchannel connects two reservoirs with constant but different concentrations of an electro-neutral solute. The electric potential distribution is obtained by solving the Poisson–Boltzmann equation using Debye–Hückel linearization under the thin electric double layer (EDL) assumption. Using this, we solve the momentum equation incorporating Lorentz forces to obtain the velocity field. The species transport equation is then analyzed using the Chatwin approximation to evaluate the effective dispersion coefficient. Our results reveal that introducing a magnetic field enhances the peak velocity by up to 4.5% and increases the effective dispersion coefficient by nearly 40% for Jeffrey fluids. Additionally, asymmetry in wall zeta potentials, higher Schmidt numbers, and increasing Womersley number significantly improve mass transport rates. These findings provide design insights for microfluidic devices such as lab-on-a-chip systems, drug delivery platforms, and biosensors, where enhanced control over flow and mixing is crucial.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204320"},"PeriodicalIF":2.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522143","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":"A complete flux scheme for Boussinesq model with applications to convection problems","authors":"Chitranjan Pandey ,&nbsp;B.V. Rathish Kumar ,&nbsp;J.H.M ten Thije Boonkkamp","doi":"10.1016/j.euromechflu.2025.204316","DOIUrl":"10.1016/j.euromechflu.2025.204316","url":null,"abstract":"<div><div>A complete-flux approximation scheme for a system of thermally-coupled Navier–Stokes equations has been proposed which has applications in convection problems. The governing equations have been discretized on a 2D staggered grid in space by finite volume method. The convective and viscous momentum fluxes are approximated by solving appropriate local nonlinear boundary value problems (BVPs). This numerical-flux approximation scheme is second order accurate and strongly depends on the transverse flux gradient, pressure gradient, and thermal buoyancy force. Similarly, the heat conduction and diffusion fluxes are approximated by solving local BVPs which have a significant influence of the thermal cross flux. The numerical validation of the scheme has been done for natural convection in a square cavity with heated bottom wall for various Prandtl and Rayleigh numbers. Furthermore, the effect of the domain’s aspect ratio on heat flux at the bottom wall has been studied for several combinations of parameters. The increase of the thermal buoyancy force leads the formation of a multicellular cat’s-eyed circulation pattern and a centrally located sharp thermal plume in the temperature field.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204316"},"PeriodicalIF":2.5,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518479","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":"Age-related anatomical variations and the impact of adenoid hypertrophy on nasal airflow in Asian children","authors":"Zhenzhen Hu ,&nbsp;Junming Chen ,&nbsp;Ya Zhang ,&nbsp;Ying Wang ,&nbsp;Yulin Zhao ,&nbsp;Guoxi Zheng ,&nbsp;Shaokoon Cheng ,&nbsp;Kiao Inthavong ,&nbsp;Jingliang Dong","doi":"10.1016/j.euromechflu.2025.204321","DOIUrl":"10.1016/j.euromechflu.2025.204321","url":null,"abstract":"<div><div>The human nasal airway grows rapidly in childhood and some children develop pathological changes of adenoid hypertrophy (AH), leading to substantial alterations in airflow dynamics. To ensure the healthy growth of children, we quantified the growth of the nasal airway and analyzed the nasal airflow field and nasal function. Models of 26 children aged 3–12 years were constructed, and the geometric dimensions of the nasal airway were quantified based on parameters such as surface area, volume, cross-sectional area, and hydraulic diameter. Computational fluid dynamics (CFD) methods were employed to simulate the nasal airflow field. Virtual adenoidectomy was performed on children with severe AH, and partitioned airflow volume and warming and humidification were quantitatively compared before and after surgery. The results showed that the turbinate area in children aged 3–12 develops most rapidly and constitutes the main form of the complex shape of the nasal cavity. The majority of airflow in children's nasal cavities passes through the main nasal passage and the middle meatus, with a small portion of the airflow passing though the olfactory fissure. After adenoidectomy, more airflow is redirected to the olfactory region, and the imbalance in airflow distribution between the left and right nasal cavities is reduced. Virtual post-operatively, the warming and humidification of the nasal cavity, especially in the nasopharynx, has decreased, which is significantly correlated with the surface area-to-volume ratio of the airway. The findings contribute to a better understanding of the growth and development of nasal airways in Asian children.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204321"},"PeriodicalIF":2.5,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144471358","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":"A flow-induced vibration energy harvester based on bioinspired shell surface bluff body","authors":"Yikai Yuan ,&nbsp;Hai Wang ,&nbsp;Chunlai Yang ,&nbsp;Bao Li ,&nbsp;Wenbo Zhu ,&nbsp;Jinsong Gui","doi":"10.1016/j.euromechflu.2025.204314","DOIUrl":"10.1016/j.euromechflu.2025.204314","url":null,"abstract":"<div><div>The bluff body is integral to a flow-induced vibration (FIV) energy harvesting system, with its aerodynamic characteristics tunable via a biomimetic metasurface. This paper proposes a FIV energy harvester utilizing a bioinspired metasurface to enhance energy harvesting performance. The mathematical model of the proposed FIV energy harvester is developed. Lift and drag coefficients are determined through numerical simulation using COMSOL. The corrugated metasurface reduces the average drag coefficient by 97.5 % and increases lift amplitude by 105 %, while the oblique stripe surface enhances drag by 106.9 % and lift amplitude by 99.3 %. Prototypes of the FIV energy harvester with bioinspired metasurfaces are fabricated and validated in a wind tunnel experimental system. Numerical and experimental results demonstrate that the performance of FIV energy harvesters can be either suppressed or enhanced by employing a bluff body with a bioinspired metasurface. At 0.5 m/s, the corrugated surface boosts output voltage by 94.24 %; at 6 m/s, the straight stripe surface achieves a 106.64 % increase. The oblique stripe metasurface improves peak voltages by up to 287.75 % at higher wind speeds. The operation bandwidth of the FIV energy harvester with a straight striped metasurface bluff body increased by nearly 277 % compared to the traditional smooth body, providing a practical method for harnessing wind energy across diverse natural environments and adapting effectively to fluctuating wind conditions.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204314"},"PeriodicalIF":2.5,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522191","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":"Experimental investigation of friction coefficient in water vapor transportation pipelines under sub-atmospheric pressure","authors":"Koosha Aghazadeh ,&nbsp;Reza Attarnejad","doi":"10.1016/j.euromechflu.2025.204319","DOIUrl":"10.1016/j.euromechflu.2025.204319","url":null,"abstract":"<div><div>This study provides a comprehensive analysis of the friction coefficient between pipe walls and water vapor under sub-atmospheric pressure conditions, highlighting its implications for the design and operational efficiency of fluid systems. Through a series of rigorous experiments, the research examines the interplay of varying temperatures, pressures, and flow rates on the performance of transmission pipes of different diameters. The findings indicate that the friction coefficient increases as pressure decreases. Notably, the ratio of the friction coefficient between vacuum and atmospheric conditions can increase significantly based on pressure, reaching values of up to 27 in laminar flow and 18 in turbulent flow. An increase in pipe diameter and flow rate under vacuum conditions correlates with a rise in the friction coefficient. It was also observed that under complete vacuum conditions, both laminar and turbulent flow have no impact on the friction coefficient, and unlike atmospheric conditions, they do not influence the graph of the friction coefficient across different Reynolds numbers. The Kooshi-Attar equation, a novel formulation derived with the assistance of artificial intelligence, has been introduced to estimate the friction coefficient at sub-atmospheric pressures. This equation demonstrates a prediction accuracy exceeding 93 %, providing a valuable analytical tool for optimizing fluid system designs.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204319"},"PeriodicalIF":2.5,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502767","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":"Where must we place obstacles in a flow to minimise its rate ?","authors":"François Bouchon,&nbsp;Laurent Chupin","doi":"10.1016/j.euromechflu.2025.204310","DOIUrl":"10.1016/j.euromechflu.2025.204310","url":null,"abstract":"<div><div>We propose a numerical method in order to determining how to place fixed obstacles in a Stokes flow, for which the inlet constraint force is imposed, so that the flow rate is minimised. To do this, we study the shape derivative associated to such a Stokes flow, and we propose a descent algorithm. We first consider the case of spherical obstacles, and then general rigid obstacles for which the orientation must be taken into account. Numerical simulations complete the study.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204310"},"PeriodicalIF":2.5,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322894","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":"A mass conservation-based model for the run-out distance of planar monodisperse particle laden gravity currents","authors":"Bruno Alvarez Scapin ,&nbsp;Bruno Avila Farenzena ,&nbsp;Karina Ruschel ,&nbsp;Jorge Hugo Silvestrini","doi":"10.1016/j.euromechflu.2025.204309","DOIUrl":"10.1016/j.euromechflu.2025.204309","url":null,"abstract":"<div><div>Turbidity currents are defined as particle-laden gravity currents, in which sediment particles in suspension cause the density difference. Even tiny density differences can generate turbidity currents that travel over significant distances. The farthest distance reached by a turbidity current is often called the run-out distance and is measured with the turbidity current deposit. This study develops an original predictive model for the run-out distance by taking as reference numerical simulations of planar particle-laden lock-release mono-disperse gravity currents. Our model is based on the initially suspended mass conservation, requires fitting parameters from deposit density data, and is analogous to the advection length for surge flows. Through numerical simulations data to find the best fit of the model parameters, run-out distance model estimations are presented as a function of the particles settling velocity and compared with numerical and experimental data. Along with this investigation, it was also verified that the run-out distance does not change after a sufficiently large Reynolds number. Finally, we present the dimensional results on the prediction of the run-out distance in function of the particle diameter. The proposed model neglects erosion processes, assumes a smooth bottom boundary, and was calibrated primarily for laboratory-scale lock-release experimental conditions.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204309"},"PeriodicalIF":2.5,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144308187","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":"A high-precision PINN method for solving a generalized Burgers–Fisher equation","authors":"Kai Zheng ,&nbsp;Haojie Wang ,&nbsp;Haoran Cao ,&nbsp;Lixu Yan ,&nbsp;Xiaoju Zhang","doi":"10.1016/j.euromechflu.2025.204306","DOIUrl":"10.1016/j.euromechflu.2025.204306","url":null,"abstract":"<div><div>This article presents a high-precision physics informed neural network (HpPINN) method to solve a class of Burgers–Fisher equation. The main difficulty is how to optimize the model to obtain highly accurate prediction solutions. For this purpose, we firstly introduce a new weighting function (WF), and use strategies such as local adaptive activation function (LAAF), training point resampler and combinatorial optimizers to train the model. The experimental results show that the accuracy of the training and test errors can reach <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>10</mn></mrow></msup></mrow></math></span>, and the relative <span><math><mrow><mi>L</mi><mn>2</mn></mrow></math></span> error can achieve <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup></mrow></math></span>. Compared to previous results, the accuracy of the HpPINN method improves 10 times nearly. Second, we discuss the computational performance of the combinatorial optimizer in different cases. Assume that the maximum number of iterations is fixed at 10<!--> <!-->000 times, this research shows that when the number of iterations <span><math><msub><mrow><mi>i</mi></mrow><mrow><mi>A</mi></mrow></msub></math></span> with the Adam optimizer is 500 and the number of iterations <span><math><msub><mrow><mi>i</mi></mrow><mrow><mi>L</mi></mrow></msub></math></span> with the L-BFGS optimizer is 9500, the training error and the relative <span><math><mrow><mi>L</mi><mn>2</mn></mrow></math></span> error are smaller. In addition, we also find that when <span><math><msub><mrow><mi>i</mi></mrow><mrow><mi>A</mi></mrow></msub></math></span> gradually decreases from 1500 to 500, the corresponding relative <span><math><mrow><mi>L</mi><mn>2</mn></mrow></math></span> error also gradually decreases, then we may infer that the relative <span><math><mrow><mi>L</mi><mn>2</mn></mrow></math></span> error is locally monotonically increasing with respect to <span><math><msub><mrow><mi>i</mi></mrow><mrow><mi>A</mi></mrow></msub></math></span>. Finally, we discuss the HpPINN method with WF and without WF respectively. By control group, we verify that the validity of the HpPINN method mainly depends on the newly introduced weighting function.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204306"},"PeriodicalIF":2.5,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144271824","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}