European Journal of Mechanics B-fluids最新文献

{"title":"Physics informed neural network modeling for MHD natural convection: Thermal radiation and cross-diffusion effects on vertical plate dynamics","authors":"S. Sarthak,&nbsp;D. Srinivasacharya","doi":"10.1016/j.euromechflu.2025.204307","DOIUrl":"10.1016/j.euromechflu.2025.204307","url":null,"abstract":"<div><div>This research introduces an innovative deep learning approach that employs Physics-Informed Neural Networks (PINNs) to simulate the complex dynamics of magnetohydrodynamic (MHD) natural convection along a vertical plate in a non-Darcy porous medium. This methodology integrates the effects of thermal radiation and cross-diffusion. By embedding physical principles directly into the loss function, PINNs leverage deep learning techniques to resolve the nonlinear and interrelated governing equations. Initially, pseudo-similarity variables are utilized to transform the governing equations and boundary conditions into their dimensionless forms. This transformation yields a system of nonlinear partial differential equations, which are subsequently solved using deep learning-based PINNs that capture the intricate interactions within the system. The study investigates how variations in learning rates, neuron configurations, and other deep learning parameters influence the model’s convergence and accuracy. Additionally, it examines the effects of boundary conditions, activation functions, and the quantities of collocation points and training data points on the loss function’s behavior. The analysis includes residuals of the neural network’s predictions across various data points, demonstrating the model’s convergence and accuracy in approximating the PDE solutions. Probability density function (PDF) of the dimensionless velocity, temperature, and concentration distributions reveal key statistical trends, highlighting dominant flow characteristics and boundary layer effects. Additionally, heatmaps provide a detailed visualization of parameter variations across the domain. The heatmaps effectively visualize these parameter-driven variations, providing a comprehensive representation of how magnetic, radiative, and cross-diffusion effects influence the fluid’s thermal and solutal behavior across the domain, highlighting the interplay between velocity, temperature, and concentration distributions under varying physical conditions. Furthermore, the study explores the impact of critical parameters on dimensionless velocity, temperature, concentration, and heat and mass transfer, with particular emphasis on the local Nusselt and Sherwood numbers, which are illustrated graphically.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204307"},"PeriodicalIF":2.5,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144297303","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":"Inferring wall-bounded coherent structures from two-dimensional turbulent fields via SHAP analysis","authors":"Samuel Molina-Casino ,&nbsp;Andrés Cremades ,&nbsp;Sergio Hoyas ,&nbsp;José I. Cardesa ,&nbsp;François Chedevergne ,&nbsp;Ricardo Vinuesa","doi":"10.1016/j.euromechflu.2025.204304","DOIUrl":"10.1016/j.euromechflu.2025.204304","url":null,"abstract":"<div><div>The analysis of coherent structures in turbulent flows is essential for understanding and controlling turbulence. Explainable Deep Learning (XDL) has been successfully used to identify the most important flow structures in turbulent channels (Cremades et al., 2024), but its computational cost grows significantly as Reynolds number increases. This study adapts the XDL framework to assess whether observations from time-resolved volumetric data of direct numerical simulations (DNS) can be inferred using two-dimensional (2D) slices. Limiting the analysis to 2D subsets reduces the cost of three-dimensional (3D) post-processing and facilitates its application to planar particle image velocimetry (PIV) experimental data. We employ SHapley Additive exPlanations (SHAP), a game-theoretic method, to identify dynamically relevant flow regions by assigning importance scores. Using DNS data from a turbulent channel flow at a friction Reynolds number of 125, we compare SHAP-based structures derived from 3D and 2D data with classically studied structures, including Q events, streaks, and vortex clusters. Our findings show that SHAP-based structures from 2D data statistically agree with those from full 3D fields and previously reported in the literature. These results underscore the potential of SHAP analyses for studying coherent structures with 2D data, enabling experimental and DNS research at higher Reynolds number.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204304"},"PeriodicalIF":2.5,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144271823","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":"Investigation of coalescence and pinch-off processes of a self-rewetting drop interacting with a liquid layer","authors":"Bashir Elbousefi,&nbsp;William Schupbach,&nbsp;Kannan N. Premnath,&nbsp;Samuel W.J. Welch","doi":"10.1016/j.euromechflu.2025.204308","DOIUrl":"10.1016/j.euromechflu.2025.204308","url":null,"abstract":"<div><div>Self-rewetting fluids (SRFs), such as long-chain alcohol solutions, are a special class of liquids with surface tension that is anomalously depends quadratically on temperature, resulting in thermocapillary flows that differ significantly from those in normal fluids (NFs). Recent interest in SRFs are mainly due to their role in enhancing fluid dynamical and thermal transport in various microgravity applications and microfluidics, while much of their fundamental processes remain unexplored. This study focuses on simulating and investigating the behavior of SRF drops interacting with a self-rewetting liquid layer under nonuniform heating conditions. In this regard, we employ a robust central moment-based lattice Boltzmann method (LBM) with a phase-field model, which incorporates three distribution functions: one for two-fluid motion with high-density ratios including the interfacial Marangoni stresses, another for interface capturing based on the conservative Allen–Cahn equation, and a third for the energy equation expressed in an axisymmetric formulation to capture three-dimensional effects efficiently. We investigate the coalescence and pinch-off processes in SRFs and compare them to those in NFs. Our simulations reveal that SRFs undergo pinch-off earlier than NFs. In SRFs, the fluid moves toward the hotter region around interfaces, which is opposite to the flow in NFs. We also observe that increasing the Ohnesorge number <span><math><mtext>Oh</mtext></math></span> suppresses the pinch-off process, highlighting the role of viscous forces relative to surface tension, which is modulated by gravity effects or the Bond number <span><math><mtext>Bo</mtext></math></span>. Furthermore, we explore how varying the dimensionless linear and quadratic sensitivity coefficients of surface tension on temperature, <span><math><msub><mrow><mi>M</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>M</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>, respectively, and the dimensionless heat flux <span><math><mi>Q</mi></math></span> influence the coalescence/pinch-off behavior. Interestingly, in SRFs increasing <span><math><msub><mrow><mi>M</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> or <span><math><mi>Q</mi></math></span> reduces the time required to pinch-off and widens the region in the <span><math><mtext>Oh</mtext></math></span>-<span><math><mtext>Bo</mtext></math></span> regime map where pinch-off occurs, when compared to the unheated cases; by contrast, in NFs, increasing <span><math><msub><mrow><mi>M</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> or <span><math><mi>Q</mi></math></span> extends the residence time prior to pinch-off and widens the region in the <span><math><mtext>Oh</mtext></math></span>-<span><math><mtext>Bo</mtext></math></span> map where coalescence occurs. These differences are shown to be due to the variations in the thermocapillary forces on the interface. Overall, we","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204308"},"PeriodicalIF":2.5,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144243117","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 steady Darcy–Brinkman–Forchheimer flow model in porous media: Comparison study of non-Darcy flow models with viscous and inertial resistances and Forchheimer coefficient","authors":"Hyun Chul Yoon ,&nbsp;S.M. Mallikarjunaiah","doi":"10.1016/j.euromechflu.2025.204303","DOIUrl":"10.1016/j.euromechflu.2025.204303","url":null,"abstract":"<div><div>A steady Darcy–Brinkman–Forchheimer flow model is studied, with a focus on inertial and viscous effects and the Forchheimer coefficient. Two non-Darcy flow models in porous media, namely the Darcy–Brinkman and linearized Brinkman flow models, are compared with the Darcy–Brinkman–Forchheimer model. To this end, a stabilized finite element method is implemented within the continuous Galerkin framework. The nonlinear fluid model is first linearized using a standard Newton’s method. To overcome the well-known numerical instability in convection-dominated problems, Grad-Div stabilization is employed with an efficient augmented Lagrangian-type penalty method. The penalty term is used to employ the block Schur complement preconditioner, which is later coupled with a Krylov-space-based iterative linear solver. Extending the 2D lid-driven cavity flow, a detailed comparative study of the flow nature is presented for a variety of Reynolds numbers and Darcy numbers combinations for different viscous and inertial resistances. Particularly for the Forchheimer parameter, interesting flow patterns of the Darcy–Brinkman–Forchheimer in the velocity components and their streamlines are presented. Through this study, we present an attractive setting for fluid flow models (including their discretizations) with a wide spectrum of viscous and inertial resistances in porous media.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204303"},"PeriodicalIF":2.5,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144253760","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":"Flow structures in two-dimensional lid-driven cavity flow: Benchmark numerical results for steady flows","authors":"Like Li ,&nbsp;James F. Klausner ,&nbsp;Renwei Mei","doi":"10.1016/j.euromechflu.2025.204313","DOIUrl":"10.1016/j.euromechflu.2025.204313","url":null,"abstract":"<div><div>High-accuracy benchmark numerical results are presented in this work for the classic two-dimensional lid-driven square cavity flow when steady solution is sought by solving the incompressible Navier-Stokes equations at various Reynolds numbers. The central-difference method with grid stretching is used to obtain the solution in stream function-vorticity formulation at Reynolds numbers as high as 30,000. A 3rd-order bi-cubic interpolation is used to precisely determine the location and strength of the vortex centers, including the primary eddy and the corner eddies. Consistent local refinement combined with a high order interpolation for the flow variables at the boundaries of the refinement region is applied to the converged flow field in order to further resolve the corner singularities. A comprehensive comparison with literature data for 2-D steady flow is presented to validate the present results. The high-resolution computational results provide substantial insight into the eddy dynamics, especially at high Reynolds number. While physically the flow in a driven cavity is neither 2-D nor steady at high Reynolds number, numerically, it is possible to obtain numerical solutions for the 2-D steady incompressible cavity flow at high Reynolds number when fine grid meshes are used. The rigorous numerical analysis and careful attention to error propagation in this work yield results of unprecedented resolution that can serve as high-quality benchmark data for future computational efforts.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204313"},"PeriodicalIF":2.5,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144253759","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":"Chemical-nonequilibrium effects in a range of hypersonic applications","authors":"Athanasios T. Margaritis ,&nbsp;Clément Scherding ,&nbsp;Olaf Marxen ,&nbsp;Peter J. Schmid ,&nbsp;Taraneh Sayadi","doi":"10.1016/j.euromechflu.2025.204273","DOIUrl":"10.1016/j.euromechflu.2025.204273","url":null,"abstract":"<div><div>In this paper we present the effect of chemical non-equilibrium on the growth of small amplitude perturbations and dominant dynamical structures in a selection of high speed wall-bounded flows. The simulations were performed using a compressible numerical solver with improvements in numerical and physical modelling. In addition, a modular open-source library for modelling real gas effects in variable atmospheric mixtures is coupled to the flow solver. Verification against the literature is performed for canonical flat-plate boundary layers and a variety of gas models, with excellent agreement observed in all cases. Simulations show that the growth of small amplitude perturbations is strongly influenced by non-equilibrium effects at high temperatures. The presence of roughness has been shown to alter the growth of perturbations in wall-bounded flows, but our work shows that this effect is more pronounced in the presence of high-enthalpy effects, with larger pressure fluctuations at the surface. Finally, the effects of chemical non-equilibrium on the dynamic structures of the flow are illustrated in the context of a jet in cross-flow, where both the separation bubble and the penetration length are altered.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204273"},"PeriodicalIF":2.5,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144243116","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 new approach for studying Scramjet inlet-isolator unstart flow","authors":"Veeraraghavan Balaji,&nbsp;K. Venkatasubbaiah","doi":"10.1016/j.euromechflu.2025.204290","DOIUrl":"10.1016/j.euromechflu.2025.204290","url":null,"abstract":"<div><div>Flow unstart problems still plague present-day hypersonic vehicles. The system of interest in this investigation is a SCRAMJET (Supersonic-Combustion Ramjet) isolator-combustor of constant cross-sectional area. The current study aims to replicate the combustion-induced unstart phenomena in the isolator through heat addition in the downstream combustor. The addition of heat in the combustor increases both the local temperature and pressure of the flow, which can effectively replicate the actual combustor boundary conditions for the upstream isolator. A density-based Computational Fluid Dynamics (CFD) solver of OpenFOAM, rhoCentralFoam, is employed to perform simulations. Turbulence is modelled using Menter’s two-equation model, <span><math><mrow><mi>k</mi><mo>−</mo><mi>ω</mi></mrow></math></span> shear stress transport. Shock-boundary layer interactions (SBLI) arising from the addition of heat manifest as a shocktrain. The effect of inlet Mach number (<span><math><mrow><msub><mrow><mi>M</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>=</mo><mn>1</mn><mo>.</mo><mn>5</mn></mrow></math></span>, 2.5, 3.5) and the effect of heat-flux (<span><math><mrow><mi>q</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>25</mn></mrow></math></span> MW/m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>, 0.5 MW/m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>, 1 MW/m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>, 2 MW/m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>) are investigated through a parametric study. It is observed that <span><math><mrow><msub><mrow><mi>M</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>=</mo><mn>1</mn><mo>.</mo><mn>5</mn></mrow></math></span> and 3.5 exhibit unstart when <span><math><mrow><mi>q</mi><mo>≥</mo><mn>1</mn></mrow></math></span> MW/m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span> whereas all the <span><math><msub><mrow><mi>M</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span>’s exhibit unstart <span><math><mrow><mi>q</mi><mo>≥</mo><mn>2</mn></mrow></math></span> MW/m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>. A stable, pseudo-steady shocktrain is also observed in the case of <span><math><mrow><msub><mrow><mi>M</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>=</mo><mn>2</mn><mo>.</mo><mn>5</mn></mrow></math></span> and <span><math><mrow><mi>q</mi><mo>=</mo><mn>1</mn></mrow></math></span> MW/m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>. Results indicate that backpressures due to heat addition and the formation, interaction between subsonic-separation bubbles are among the top factors that cause unstart. Higher inlet Mach numbers favour the formation of separation bubbles, and higher heat fluxes cause accelerated unstart. The present methodology has been validated with the experimental results available in the literature.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204290"},"PeriodicalIF":2.5,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144190309","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":"Multi-objective optimization design method for single-blade centrifugal pump impellers to improve performance and reduce radial thrust","authors":"Yasuyuki Nishi ,&nbsp;Keito Konno ,&nbsp;Satoshi Ono","doi":"10.1016/j.euromechflu.2025.204311","DOIUrl":"10.1016/j.euromechflu.2025.204311","url":null,"abstract":"<div><div>This study aims to develop a multi-objective optimization design method to achieve performance improvement and radial thrust reduction for single-blade centrifugal pump impellers based on given specifications. To this end, the previously developed one-dimensional design method of single-blade centrifugal impellers was combined with Latin hypercube sampling, three-dimensional unsteady CFD analysis, Deep Neural Network, and multi-objective optimization method. Multi-objective optimization was performed using pump efficiency, head coefficient, and the root mean square of radial thrust coefficient as objective functions. The optimized impeller obtained showed approximately 3.5 % improvement in pump efficiency, about 18.1 % improvement in head coefficient, and around 17.1 % reduction in the root mean square of radial thrust coefficient in CFD analysis values compared to the original impeller obtained solely by the one-dimensional design method. The experimental validation showed that the optimized impeller improved pump efficiency by approximately 3.6 %, head coefficient by about 19.4 % compared to the original impeller, and demonstrated the usefulness of this optimization design method.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204311"},"PeriodicalIF":2.5,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144194769","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":"Intrinsic role of Lagrangian and Stokes drift owed to currents in a stratified three-layered channel with interfacial tensions","authors":"Deepali Goyal,&nbsp;S.C. Martha","doi":"10.1016/j.euromechflu.2025.204288","DOIUrl":"10.1016/j.euromechflu.2025.204288","url":null,"abstract":"<div><div>The present study analyses the trajectories of the fluid particles, Stokes drift and Lagrangian drift mechanisms for three-layered internal flow having two interfaces with interfacial tensions. The three-fluid layers are of different densities. A uniform and two dimensional current is flowing in each fluid layer. The pathline equations with first-order solution analysis produces closed trajectories. The trajectories of the fluid particles in the middle layer shows non-monotonic trend as it is subjected to two interfaces and get shorten according to the strength of density stratification and interfacial tensions. The analytical expressions for Stokes drift are found in each layer using small-excursion principle. Based on these expressions, we found that the variation in density causes the Stokes drift displacement to increase more robustly after a critical density ratio for both interfaces. The underlying mechanism of this behaviour is the phase reversal phenomenon which is analysed via phase plane analysis. The trajectories in spatial phase plane are open implying that Stokes drift occurs in each fluid layer. Moreover, the change in density ratio alters the direction of these open trajectories in middle layer at both interfaces, which are shown by drawing their directional fields. The expressions for Lagrangian drift which are dependent on density variations and interfacial tensions are analysed by the ratio of Eulerian return flow to the depth averaged Stokes drift at both interfaces. It is found that weak stratification with higher tension at interface lead to dominance of Eulerian return flow over averaged Stokes drift for middle layer. Also, the effect of these parameters are predominant in the intermediate wave regimes. These observations are essential for understanding the wave characteristics, sediment movement, anticipating the dispersal of contaminants, and modelling climate-related processes like the spread of heat and carbon. Therefore, the study of multilayer systems with Stokes and Lagrangian drift has a considerable potential to further our understanding of marine processes, especially in areas where internal wave action and substantial stratification are present.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204288"},"PeriodicalIF":2.5,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144116454","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":"Modeling of tuned liquid dampers with paddles: Hydrodynamic effects and estimation","authors":"Andong Wang ,&nbsp;Zijie Zhou ,&nbsp;Lanfang Zhang ,&nbsp;Zhuangning Xie","doi":"10.1016/j.euromechflu.2025.204305","DOIUrl":"10.1016/j.euromechflu.2025.204305","url":null,"abstract":"<div><div>The hydrodynamic coefficients of internal damping devices, including drag coefficient <em>C</em>_d and inertia coefficient <em>C</em>_m, are crucial parameters affecting the damping and frequency design of the tuned liquid damper (TLD). However, studies on their variation laws are few. This paper presents an approach for estimating paddle hydrodynamic coefficients under harmonic excitation. An equivalent mechanical model (EMM) of the TLD, incorporating <em>C</em>_d and <em>C</em>_m of the paddles, is developed using potential flow theory. The computational fluid dynamics (CFD) method is employed to obtain the TLD’s steady-state response. The discrepancy between the EMM and CFD model responses is then utilized as the objective function and optimized using an improved Archimedes algorithm to determine <em>C</em>_d and <em>C</em>_m. On the basis of the above, a comprehensive parameter analysis is conducted for the TLD with paddles, and the effects of paddle dimension, water depth, and harmonic excitation amplitude on <em>C</em>_d and <em>C</em>_m are examined. Two new dimensionless parameters are introduced based on the Keulegan–Carpenter (KC) number to obtain the empirical formulas for <em>C</em>_d and <em>C</em>_m with superior fitting accuracy. The findings demonstrate that the wave height and base shear force predicted by the EMM generally agree with the CFD results. Compared with the previous constant <em>C</em>_m (<em>C</em>_m = 1), the proposed nonlinear empirical formula for <em>C</em>_m exhibits better accuracy in predicting paddle force and natural sloshing frequency shift generated by the paddles.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"114 ","pages":"Article 204305"},"PeriodicalIF":2.5,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099484","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}