Pub Date : 2026-01-01Epub Date: 2025-10-10DOI: 10.1016/j.euromechflu.2025.204388
Qingchun Zhou, Xiaowei Liu, Chunji Hu
Active rotation is commonly employed in traditional enhanced heat dissipation applications. However, passive rotation, which operates without external energy input, leverages environmental energy more effectively, showing great potential for enhanced heat transfer applications. This study explores the impact of passive rotation on the heat transfer characteristics of single-degree-of-freedom transverse vibrations in circular cylinders and square prisms. Numerical simulations were performed under the conditions of Re = 100, m* = 2, ζ = 0, and Pr = 0.7. The results show that the rotational degree of freedom has minimal influence on the heat transfer of circular cylinders, with only a 1.11 % increase in Nusselt number. In contrast, it significantly enhances heat transfer in square prisms, leading to a 14.21 % increase. Further analysis reveals that the rotational degree of freedom transitions the vibration mode from pure vortex-induced vibration (VIV) to a combination of VIV and galloping, which is the primary mechanism behind the heat transfer enhancement. Flow field analysis indicates that this transition strengthens vortex intensity and disturbs the thermal boundary layer, providing a microscopic explanation for the observed heat transfer improvements. The introduction of rotational freedom in such systems offers a novel and effective approach to enhance heat transfer performance.
{"title":"Study on the influence of the rotational degree of freedom on the heat transfer of single-y vibrating blunt bodies","authors":"Qingchun Zhou, Xiaowei Liu, Chunji Hu","doi":"10.1016/j.euromechflu.2025.204388","DOIUrl":"10.1016/j.euromechflu.2025.204388","url":null,"abstract":"<div><div>Active rotation is commonly employed in traditional enhanced heat dissipation applications. However, passive rotation, which operates without external energy input, leverages environmental energy more effectively, showing great potential for enhanced heat transfer applications. This study explores the impact of passive rotation on the heat transfer characteristics of single-degree-of-freedom transverse vibrations in circular cylinders and square prisms. Numerical simulations were performed under the conditions of <em>Re</em> = 100, <em>m</em>* = 2, <em>ζ</em> = 0, and <em>Pr</em> = 0.7. The results show that the rotational degree of freedom has minimal influence on the heat transfer of circular cylinders, with only a 1.11 % increase in Nusselt number. In contrast, it significantly enhances heat transfer in square prisms, leading to a 14.21 % increase. Further analysis reveals that the rotational degree of freedom transitions the vibration mode from pure vortex-induced vibration (VIV) to a combination of VIV and galloping, which is the primary mechanism behind the heat transfer enhancement. Flow field analysis indicates that this transition strengthens vortex intensity and disturbs the thermal boundary layer, providing a microscopic explanation for the observed heat transfer improvements. The introduction of rotational freedom in such systems offers a novel and effective approach to enhance heat transfer performance.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"115 ","pages":"Article 204388"},"PeriodicalIF":2.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266752","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}
Pub Date : 2026-01-01Epub Date: 2025-09-02DOI: 10.1016/j.euromechflu.2025.204345
Deepak Kumar, Subramaniam Pushpavanam
Aqueous humor dynamics is responsible for maintaining intraocular pressure, ocular health and targeted drug delivery within the eye. This study investigates the flow of AH within the anterior chamber under the combined influence of a uniform magnetic field and natural convection. Different orientations of the magnetic field and temperature gradient are considered. A lubrication approximation is employed and the resulting equations are solved using regular perturbation method. The analytical solutions are validated using numerical simulations performed in COMSOL Multiphysics 6.2protect relax special {t4ht=®}. In the standing position, AH flow field is characterized by a single vortex, while in the supine position, it forms two counter-rotating vortices. The velocity is found to be higher in standing position. The effect of a uniform magnetic field on the velocity is more significant in the supine position. The magnetic field does not change the flow field qualitatively as buoyancy is the primary driving force. In the standing position a magnetic field oriented perpendicular to the eye resulted in a greatest reduction of AH velocity, as compared to a magnetic field along the eye. The use of magnetic fields is being considered as a disruptive technology in ocular treatment. This study establishes that magnetic fields provide a holistic approach for targeted drug delivery in ocular treatment. They can be used without fear of any risks as the flow patterns in AH are not qualitatively modified.
房水动力学负责维持眼压、眼健康和眼内靶向药物输送。本研究考察了均匀磁场和自然对流共同作用下前房AH的流动情况。考虑了不同方向的磁场和温度梯度。采用润滑近似，用正则摄动法求解得到的方程。利用COMSOL Multiphysics 6.2protect relax special {t4ht=®}进行的数值模拟验证了解析解的有效性。在站立位置时，AH流场的特征为单个涡，而在仰卧位置时，它形成两个反向旋转的涡。发现站姿时速度更高。平卧位时，均匀磁场对速度的影响更为显著。由于浮力是主要的驱动力，磁场不会对流场产生质的改变。与沿眼睛方向的磁场相比，在站立位置垂直于眼睛方向的磁场导致AH速度的最大降低。磁场的使用被认为是眼部治疗中的一项颠覆性技术。本研究确定磁场为眼部治疗的靶向药物递送提供了一种整体方法。它们可以使用而不必担心任何风险，因为AH中的流模式没有进行定性修改。
{"title":"How safe are magnetic fields in enhancing drug delivery in ocular treatment? Hydrodynamic aspects","authors":"Deepak Kumar, Subramaniam Pushpavanam","doi":"10.1016/j.euromechflu.2025.204345","DOIUrl":"10.1016/j.euromechflu.2025.204345","url":null,"abstract":"<div><div>Aqueous humor dynamics is responsible for maintaining intraocular pressure, ocular health and targeted drug delivery within the eye. This study investigates the flow of AH within the anterior chamber under the combined influence of a uniform magnetic field and natural convection. Different orientations of the magnetic field and temperature gradient are considered. A lubrication approximation is employed and the resulting equations are solved using regular perturbation method. The analytical solutions are validated using numerical simulations performed in COMSOL Multiphysics 6.2<sup>protect relax special {t4ht=®}</sup>. In the standing position, AH flow field is characterized by a single vortex, while in the supine position, it forms two counter-rotating vortices. The velocity is found to be higher in standing position. The effect of a uniform magnetic field on the velocity is more significant in the supine position. The magnetic field does not change the flow field qualitatively as buoyancy is the primary driving force. In the standing position a magnetic field oriented perpendicular to the eye resulted in a greatest reduction of AH velocity, as compared to a magnetic field along the eye. The use of magnetic fields is being considered as a disruptive technology in ocular treatment. This study establishes that magnetic fields provide a holistic approach for targeted drug delivery in ocular treatment. They can be used without fear of any risks as the flow patterns in AH are not qualitatively modified.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"115 ","pages":"Article 204345"},"PeriodicalIF":2.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145026325","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}
Pub Date : 2026-01-01Epub Date: 2025-09-22DOI: 10.1016/j.euromechflu.2025.204373
Sameer Kumar Sanu, Tanmoy Mondal
This study presents a numerical investigation of two plane parallel turbulent buoyant jets (TPBJ) to examine the combined effects of jet spacing and buoyancy on flow interaction and thermal transport. Steady-state simulations are conducted by solving the Reynolds-averaged Navier–Stokes equations using the standard turbulence model with the Boussinesq approximation. The analysis considers jet spacing ratios ( to 11), where is the centre-to-centre jet spacing and is the nozzle width, and Richardson numbers ( to 1/2) to represent varying buoyancy levels. Results indicate that narrower spacing enhances jet interaction, strengthens entrainment, and leads to earlier merging, while wider spacing delays interaction and weakens vertical momentum. Buoyancy significantly alters the flow structure by accelerating jet convergence, increasing centreline velocity, and confining both velocity and thermal plumes. Three characteristic axial locations, namely, the merging point (MP), combined point (CP), and maximum velocity point (MVP), are identified and correlated with and . In the far field, the lateral growth of velocity and thermal widths becomes approximately linear, though spreading rates decrease with increasing buoyancy. The centreline velocity and temperature exhibit decay consistent with power-law behaviour, influenced by buoyancy strength. Empirical correlations are proposed to predict the axial positions of MP, CP, and MVP with high accuracy. These correlations can be directly applied in engineering design and environmental applications, including the optimization of jet-based cooling configurations, ventilation layouts, and buoyant discharge systems, where a rapid yet reliable estimation of jet interaction characteristics is essential. Compared to isothermal jets (), buoyant jets show enhanced centreline velocities, stronger recirculation, and reduced lateral dispersion. These findings provide new insights into the coupled momentum and thermal dynamics of TPBJ systems and offer predictive tools for applications in thermal management and environmental jet discharge.
{"title":"Numerical investigation of two plane parallel turbulent buoyant jets: Effects of jet spacing and Richardson number on flow interaction and thermal transport","authors":"Sameer Kumar Sanu, Tanmoy Mondal","doi":"10.1016/j.euromechflu.2025.204373","DOIUrl":"10.1016/j.euromechflu.2025.204373","url":null,"abstract":"<div><div>This study presents a numerical investigation of two plane parallel turbulent buoyant jets (TPBJ) to examine the combined effects of jet spacing and buoyancy on flow interaction and thermal transport. Steady-state simulations are conducted by solving the Reynolds-averaged Navier–Stokes equations using the standard <span><math><mrow><mi>k</mi><mo>−</mo><mi>ϵ</mi></mrow></math></span> turbulence model with the Boussinesq approximation. The analysis considers jet spacing ratios (<span><math><mrow><mi>s</mi><mo>/</mo><mi>d</mi><mo>=</mo><mn>3</mn></mrow></math></span> to 11), where <span><math><mi>s</mi></math></span> is the centre-to-centre jet spacing and <span><math><mi>d</mi></math></span> is the nozzle width, and Richardson numbers (<span><math><mrow><mi>R</mi><mi>i</mi><mo>=</mo><mn>0</mn></mrow></math></span> to 1/2) to represent varying buoyancy levels. Results indicate that narrower spacing enhances jet interaction, strengthens entrainment, and leads to earlier merging, while wider spacing delays interaction and weakens vertical momentum. Buoyancy significantly alters the flow structure by accelerating jet convergence, increasing centreline velocity, and confining both velocity and thermal plumes. Three characteristic axial locations, namely, the merging point (MP), combined point (CP), and maximum velocity point (MVP), are identified and correlated with <span><math><mrow><mi>s</mi><mo>/</mo><mi>d</mi></mrow></math></span> and <span><math><mrow><mi>R</mi><mi>i</mi></mrow></math></span>. In the far field, the lateral growth of velocity and thermal widths becomes approximately linear, though spreading rates decrease with increasing buoyancy. The centreline velocity and temperature exhibit decay consistent with power-law behaviour, influenced by buoyancy strength. Empirical correlations are proposed to predict the axial positions of MP, CP, and MVP with high accuracy. These correlations can be directly applied in engineering design and environmental applications, including the optimization of jet-based cooling configurations, ventilation layouts, and buoyant discharge systems, where a rapid yet reliable estimation of jet interaction characteristics is essential. Compared to isothermal jets (<span><math><mrow><mi>R</mi><mi>i</mi><mo>=</mo><mn>0</mn></mrow></math></span>), buoyant jets show enhanced centreline velocities, stronger recirculation, and reduced lateral dispersion. These findings provide new insights into the coupled momentum and thermal dynamics of TPBJ systems and offer predictive tools for applications in thermal management and environmental jet discharge.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"115 ","pages":"Article 204373"},"PeriodicalIF":2.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217833","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}
Pub Date : 2026-01-01Epub Date: 2025-09-25DOI: 10.1016/j.euromechflu.2025.204380
Xinwei Ye , Xiaojing Niu
This study aims to elucidate the motion and the evolution of shedding vortices in the wake of a wobbling bubble based on experimental observation. Experimental observations of bubble wakes were conducted using Particle Image Velocimetry (PIV) for the ambient continuous phase and the backlight shadow imaging technique for the bubble. Vortices are detected and tracked in a Lagrangian framework based on the flow field in the vertical section. To investigate the three-dimensional structure of the flow field and to supplement the experimentally measured bubble sizes, bubbles with a diameter of 3–5 mm are numerically simulated, incorporating adaptive dynamic mesh refinement based on the bubble wake location. The study establishes a correlation between the transport velocity and swirling strength of wake vortices generated by wobbling bubbles and the bubble's parameters, facilitating more convenient predictions of wake behavior. The results indicate that the vortices trail the bubble at a transport velocity that is approximately 30 % of the bubbles’ velocity. During the vortex shedding process, the swirling strength of these vortices intensifies within a distance of 1.58 times the bubble radius and then decays with increasing distance from the bubble, following the formula of .
{"title":"Lagrangian tracking of the wake vortices shedding from a wobbling bubble","authors":"Xinwei Ye , Xiaojing Niu","doi":"10.1016/j.euromechflu.2025.204380","DOIUrl":"10.1016/j.euromechflu.2025.204380","url":null,"abstract":"<div><div>This study aims to elucidate the motion and the evolution of shedding vortices in the wake of a wobbling bubble based on experimental observation. Experimental observations of bubble wakes were conducted using Particle Image Velocimetry (PIV) for the ambient continuous phase and the backlight shadow imaging technique for the bubble. Vortices are detected and tracked in a Lagrangian framework based on the flow field in the vertical section. To investigate the three-dimensional structure of the flow field and to supplement the experimentally measured bubble sizes, bubbles with a diameter of 3–5 mm are numerically simulated, incorporating adaptive dynamic mesh refinement based on the bubble wake location. The study establishes a correlation between the transport velocity and swirling strength of wake vortices generated by wobbling bubbles and the bubble's parameters, facilitating more convenient predictions of wake behavior. The results indicate that the vortices trail the bubble at a transport velocity that is approximately 30 % of the bubbles’ velocity. During the vortex shedding process, the swirling strength of these vortices intensifies within a distance of 1.58 times the bubble radius and then decays with increasing distance from the bubble, following the formula of <span><math><mrow><mn>1</mn><mo>−</mo><mi>exp</mi><mrow><mo>(</mo><mrow><mo>−</mo><mn>1.75</mn><mo>/</mo><mi>x</mi></mrow><mo>)</mo></mrow></mrow></math></span>.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"115 ","pages":"Article 204380"},"PeriodicalIF":2.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217837","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}
Pub Date : 2026-01-01Epub Date: 2025-08-27DOI: 10.1016/j.euromechflu.2025.204352
Ziyuan Xu , Shenglong Gu , Hang Wang
We propose a hybrid model driven by both data and physics, termed Double-branched Physics-Informed Neural Network (Db-PINN), which enhances the synergy between data-driven and physical mechanisms methods, effectively improving the accuracy of predicting the hydraulic jump flow field and energy dissipation rate. The core architecture of the model is based on Convolutional Neural Networks (CNNs), which extract detailed features of the hydraulic jump flow field. In combination with a branch network, Deep Neural Networks (DNNs) are used to compute the residuals of partial differential equations, ensuring adherence to physical laws. Additionally, considering hardware resource constraints, the Db-PINN model incorporates a mini-batch algorithm to reduce dependence on GPU memory size, thus meeting the model’s need to process large-scale datasets. When compared to numerical simulation results, the model demonstrates high accuracy and generalization capability in predicting the velocity distribution and turbulence characteristics of the hydraulic jump flow field.
{"title":"Application of the Db-PINN model in predicting hydraulic jump flow fields under different Froude numbers","authors":"Ziyuan Xu , Shenglong Gu , Hang Wang","doi":"10.1016/j.euromechflu.2025.204352","DOIUrl":"10.1016/j.euromechflu.2025.204352","url":null,"abstract":"<div><div>We propose a hybrid model driven by both data and physics, termed Double-branched Physics-Informed Neural Network (Db-PINN), which enhances the synergy between data-driven and physical mechanisms methods, effectively improving the accuracy of predicting the hydraulic jump flow field and energy dissipation rate. The core architecture of the model is based on Convolutional Neural Networks (CNNs), which extract detailed features of the hydraulic jump flow field. In combination with a branch network, Deep Neural Networks (DNNs) are used to compute the residuals of partial differential equations, ensuring adherence to physical laws. Additionally, considering hardware resource constraints, the Db-PINN model incorporates a mini-batch algorithm to reduce dependence on GPU memory size, thus meeting the model’s need to process large-scale datasets. When compared to numerical simulation results, the model demonstrates high accuracy and generalization capability in predicting the velocity distribution and turbulence characteristics of the hydraulic jump flow field.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"115 ","pages":"Article 204352"},"PeriodicalIF":2.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005382","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}
Pub Date : 2026-01-01Epub Date: 2025-10-11DOI: 10.1016/j.euromechflu.2025.204391
Zihao Zhao, Lingyun Tian, Xiaoyang Xu
This paper proposes an improved multi-resolution smooth particle hydrodynamics (SPH) method for efficiently and accurately simulating the free surface flow of viscous fluids. To address the numerical instabilities arising from interactions between coarse and fine particles due to differences in smoothing length, this study proposes a particle refinement method inspired by adaptive mesh refinement (AMR) and introduces a multi-layer background grid coupling mechanism to improve numerical accuracy while maintaining computational efficiency. To resolve physical field discontinuities at the interface between refined and non-refined regions due to the truncation of the smoothing kernel, buffer particles (including child guard and parent guard particles) are introduced on both sides of the refined region. The physical properties of hidden parent guard particles are updated by fine particles within the fine background grid, ensuring a smooth transition of physical quantities between coarse and fine particle regions. To mitigate tensile instability caused by irregular particle distribution, the particle shifting technique is further enhanced, improving the stability of multi-resolution simulations. Finally, comparisons with single-resolution simulations of dam-break flow, hydrostatic water column, and F-shaped cavity flow demonstrate that the proposed method significantly improves computational efficiency while maintaining high accuracy, thus confirming its effectiveness and robustness.
{"title":"An improved weakly compressible multi-resolution SPH method for free-surface flow simulation","authors":"Zihao Zhao, Lingyun Tian, Xiaoyang Xu","doi":"10.1016/j.euromechflu.2025.204391","DOIUrl":"10.1016/j.euromechflu.2025.204391","url":null,"abstract":"<div><div>This paper proposes an improved multi-resolution smooth particle hydrodynamics (SPH) method for efficiently and accurately simulating the free surface flow of viscous fluids. To address the numerical instabilities arising from interactions between coarse and fine particles due to differences in smoothing length, this study proposes a particle refinement method inspired by adaptive mesh refinement (AMR) and introduces a multi-layer background grid coupling mechanism to improve numerical accuracy while maintaining computational efficiency. To resolve physical field discontinuities at the interface between refined and non-refined regions due to the truncation of the smoothing kernel, buffer particles (including child guard and parent guard particles) are introduced on both sides of the refined region. The physical properties of hidden parent guard particles are updated by fine particles within the fine background grid, ensuring a smooth transition of physical quantities between coarse and fine particle regions. To mitigate tensile instability caused by irregular particle distribution, the particle shifting technique is further enhanced, improving the stability of multi-resolution simulations. Finally, comparisons with single-resolution simulations of dam-break flow, hydrostatic water column, and F-shaped cavity flow demonstrate that the proposed method significantly improves computational efficiency while maintaining high accuracy, thus confirming its effectiveness and robustness.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"115 ","pages":"Article 204391"},"PeriodicalIF":2.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333159","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}
Pub Date : 2026-01-01Epub Date: 2025-10-14DOI: 10.1016/j.euromechflu.2025.204394
Erik Lindborg
In recent years, several studies have been made in which atmospheric and oceanic data were used to decompose horizontal velocity statistics into a rotational component, associated with vertical vorticity, and a divergent component, associated with horizontal divergence. The decomposition methods rely on the assumption of statistical isotropy. In this paper, the full anisotropic equations relating the rotational, divergent and the rotational-divergent components of the second order velocity structure function tensor to the longitudinal, transverse and longitudinal–transverse components are formulated and solved analytically.
{"title":"A complete Helmholtz decomposition of second order horizontal velocity structure functions","authors":"Erik Lindborg","doi":"10.1016/j.euromechflu.2025.204394","DOIUrl":"10.1016/j.euromechflu.2025.204394","url":null,"abstract":"<div><div>In recent years, several studies have been made in which atmospheric and oceanic data were used to decompose horizontal velocity statistics into a rotational component, associated with vertical vorticity, and a divergent component, associated with horizontal divergence. The decomposition methods rely on the assumption of statistical isotropy. In this paper, the full anisotropic equations relating the rotational, divergent and the rotational-divergent components of the second order velocity structure function tensor to the longitudinal, transverse and longitudinal–transverse components are formulated and solved analytically.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"115 ","pages":"Article 204394"},"PeriodicalIF":2.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333164","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}
Turbulence modeling poses significant challenges due to its nonlinear, multiscale nature. Classical methods like Reynolds-Averaged Navier–Stokes and Large Eddy Simulation often rely on empirical closures, which limit their accuracy in complex flows. This study aims to propose a hybrid model that integrates convolutional neural networks for capturing local spatial patterns with Transformer-based attention modules to model long-range dependencies. The architecture is informed by the Navier–Stokes equations and incorporates divergence-free constraints to preserve physical fidelity. The model is trained and evaluated on direct numerical simulation datasets representing 2D turbulence and turbulent channel flows. The model achieved up to 40 % reduction in prediction error compared to CNN and RNN baselines. It accurately reproduced key flow structures and energy spectra, showing strong agreement with DNS outputs. The hybrid architecture demonstrated stable long-term predictions and matched statistical flow properties over extended time horizons. For steady flows, it corrected RANS-predicted biases in mean velocity profiles with near-exact reconstruction. The results validate the effectiveness of combining physics-informed learning with deep neural architectures. The proposed framework offers a computationally efficient alternative to traditional turbulence models while retaining accuracy, marking a promising advancement in data-driven fluid mechanics.
湍流建模由于其非线性、多尺度的特性而面临着巨大的挑战。像reynolds - average Navier-Stokes和大涡模拟等经典方法通常依赖于经验闭包，这限制了它们在复杂流动中的准确性。本研究旨在提出一种混合模型，该模型将卷积神经网络与基于transformer的注意力模块集成在一起，用于捕获局部空间模式，以模拟远程依赖关系。建筑由Navier-Stokes方程提供信息，并结合无散度约束以保持物理保真度。该模型在二维湍流和湍流通道流的直接数值模拟数据集上进行了训练和评估。与CNN和RNN基线相比，该模型的预测误差降低了40% %。它准确地再现了关键流结构和能谱，与DNS输出结果具有很强的一致性。混合架构显示出稳定的长期预测，并在较长的时间范围内匹配统计流特性。对于稳定流，它通过近乎精确的重建纠正了ranss预测的平均速度剖面偏差。结果验证了将物理信息学习与深度神经结构相结合的有效性。该框架为传统湍流模型提供了一种计算效率高的替代方案，同时保持了准确性，标志着数据驱动流体力学的一个有希望的进步。
{"title":"A physics-embedded Transformer-CNN architecture for data-driven turbulence prediction and surrogate modeling of high-fidelity fluid dynamics","authors":"Sukanta Ghosh , Vinod Kumar Shukla , Amar Singh , Jayanta Chanda","doi":"10.1016/j.euromechflu.2025.204372","DOIUrl":"10.1016/j.euromechflu.2025.204372","url":null,"abstract":"<div><div>Turbulence modeling poses significant challenges due to its nonlinear, multiscale nature. Classical methods like Reynolds-Averaged Navier–Stokes and Large Eddy Simulation often rely on empirical closures, which limit their accuracy in complex flows. This study aims to propose a hybrid model that integrates convolutional neural networks for capturing local spatial patterns with Transformer-based attention modules to model long-range dependencies. The architecture is informed by the Navier–Stokes equations and incorporates divergence-free constraints to preserve physical fidelity. The model is trained and evaluated on direct numerical simulation datasets representing 2D turbulence and turbulent channel flows. The model achieved up to 40 % reduction in prediction error compared to CNN and RNN baselines. It accurately reproduced key flow structures and energy spectra, showing strong agreement with DNS outputs. The hybrid architecture demonstrated stable long-term predictions and matched statistical flow properties over extended time horizons. For steady flows, it corrected RANS-predicted biases in mean velocity profiles with near-exact reconstruction. The results validate the effectiveness of combining physics-informed learning with deep neural architectures. The proposed framework offers a computationally efficient alternative to traditional turbulence models while retaining accuracy, marking a promising advancement in data-driven fluid mechanics.</div></div>","PeriodicalId":11985,"journal":{"name":"European Journal of Mechanics B-fluids","volume":"115 ","pages":"Article 204372"},"PeriodicalIF":2.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106556","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}
The hydrodynamic coefficients of internal damping devices, including drag coefficient Cd and inertia coefficient Cm, 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 Cd and Cm 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 Cd and Cm. 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 Cd and Cm are examined. Two new dimensionless parameters are introduced based on the Keulegan–Carpenter (KC) number to obtain the empirical formulas for Cd and Cm 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 Cm (Cm = 1), the proposed nonlinear empirical formula for Cm exhibits better accuracy in predicting paddle force and natural sloshing frequency shift generated by the paddles.
{"title":"Modeling of tuned liquid dampers with paddles: Hydrodynamic effects and estimation","authors":"Andong Wang , Zijie Zhou , Lanfang Zhang , 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><sub>d</sub> and inertia coefficient <em>C</em><sub>m</sub>, 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><sub>d</sub> and <em>C</em><sub>m</sub> 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><sub>d</sub> and <em>C</em><sub>m</sub>. 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><sub>d</sub> and <em>C</em><sub>m</sub> are examined. Two new dimensionless parameters are introduced based on the Keulegan–Carpenter (KC) number to obtain the empirical formulas for <em>C</em><sub>d</sub> and <em>C</em><sub>m</sub> 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><sub>m</sub> (<em>C</em><sub>m</sub> = 1), the proposed nonlinear empirical formula for <em>C</em><sub>m</sub> 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":"2025-11-01","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}
Pub Date : 2025-11-01Epub Date: 2025-05-31DOI: 10.1016/j.euromechflu.2025.204273
Athanasios T. Margaritis , Clément Scherding , Olaf Marxen , Peter J. Schmid , Taraneh Sayadi
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.
{"title":"Chemical-nonequilibrium effects in a range of hypersonic applications","authors":"Athanasios T. Margaritis , Clément Scherding , Olaf Marxen , Peter J. Schmid , 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":"2025-11-01","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号