Journal of Fluids and Structures最新文献_第2页

Mathematical modeling of nonlinear coupled along- and across-wind aeroelastic responses in tall slender structures with square section 方形截面高细长结构非线性耦合顺、横风气动弹性响应的数学建模

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2026-01-15 DOI: 10.1016/j.jfluidstructs.2026.104514

Shuai Huang , Qingshan Yang , Zhanfang Liu , Haohong Li , Wenshan Shan , Chen Li

Tall slender structures are prone to aeroelastic instability, such as vortex resonance and galloping, in which the along-wind response is often neglected in conventional analyses. Recent experimental studies, however, have shown that near the wind speed corresponding to across-wind resonance, the along-wind vibration becomes coupled with the across-wind vibration, resulting in a significant amplification of the along-wind response and a reduction of the across-wind response. The underlying nonlinear self-excited forces driving this coupled behavior remain insufficiently understood. This study proposes a method for identifying the self-excited forces of tall slender structures accounting for along- and across-wind coupling. Displacement responses in both directions were measured through wind tunnel tests using a pivot model, followed by complex modal parameter identification. It was found that the mode with a frequency close to the across-wind natural frequency predominantly governs the structural response. A mathematical model was then established to predict coupled vibrations and to identify nonlinear self-excited forces. A generalized Van der Pol-type damping model was employed to capture the amplitude dependence of the first-mode damping ratio. Finally, the prediction model and the self-excited force identification method were validated against experimental results. The proposed approach provides a theoretical framework for analyzing aeroelastic instability of tall slender structures with along- and across-wind coupling effects.

细长高架结构容易发生涡共振和驰动等气动弹性失稳，而在这些失稳中，沿风响应在传统分析中往往被忽略。然而，最近的实验研究表明，在横风共振对应的风速附近，顺风振动与横风振动耦合，导致顺风响应明显放大，横风响应减弱。驱动这种耦合行为的潜在非线性自激力仍然没有得到充分的了解。本文提出了一种考虑顺风和横风耦合的高细长结构自激力识别方法。采用主轴模型进行风洞试验，测量了两个方向的位移响应，然后进行了复杂模态参数辨识。研究发现，接近横风固有频率的模态主导结构响应。然后建立数学模型来预测耦合振动和识别非线性自激力。采用广义Van der pol型阻尼模型来捕捉第一模态阻尼比的幅值依赖性。最后，根据实验结果对预测模型和自激力识别方法进行了验证。该方法为分析具有顺风和横风耦合效应的高细长结构的气动弹性失稳提供了理论框架。

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引用次数: 0

Interplay between shock-induced panel flutter and the Kelvin-Helmholtz instability in laminar flow 层流中激波诱导板颤振与开尔文-亥姆霍兹不稳定性的相互作用

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2026-01-13 DOI: 10.1016/j.jfluidstructs.2025.104497

James L. Fields , Anshul Suri , Caleb J. Barnes , Jack J. McNamara , Datta V. Gaitonde

This paper investigates the interplay between the Kelvin-Helmholtz (K-H) instability, aeroelastic flutter, and laminar shock-boundary layer interactions. The coupled system is studied by performing modal-based analyses over distinct phases of the aeroelastic response. The initial response is comparable to classical panel flutter and is dominated by first- and second-mode panel deflections. Over time, a frequency lock-in occurs between K-H waves in the flow and high-order modes in the panel, resulting in mutual growth. The growth of the K-H instability leads to a period of cascading frequency and modal content in which energy is channeled into several discrete oscillating panel modes. It is shown through a bispectral mode decomposition that the frequency cascade is driven by nonlinear interactions between panel modes. The asymptotic state of the aeroelastic system is classified as a multi-mode limit cycle oscillation and exhibits a traveling wave flutter. The time-mean flow field exhibits reductions in both the separation bubble volume and downstream boundary layer thickness in the presence of the fluttering panel, supporting the notion of fluid-structure interaction as a means for passive flow control of SBLIs.

本文研究了开尔文-亥姆霍兹（K-H）不稳定性、气动弹性颤振和层流激波-边界层相互作用之间的相互作用。通过对气动弹性响应的不同阶段进行基于模态的分析来研究耦合系统。初始响应与经典板颤振相当，主要受一模和二模板挠度的影响。随着时间的推移，流动中的K-H波和面板中的高阶模态之间发生频率锁定，导致相互增长。K-H不稳定性的增长导致了一段时间的级联频率和模态含量，在此期间能量被引导到几个离散的振荡面板模态。通过双谱模式分解表明，频率级联是由面板模式之间的非线性相互作用驱动的。气动弹性系统的渐近状态为多模态极限环振荡，表现为行波颤振。在颤振板存在的情况下，时间平均流场表现出分离泡体积和下游边界层厚度的减小，这支持了流固耦合作为SBLIs被动流动控制手段的概念。

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引用次数: 0

Hydrodynamic study of a novel surface standing-and-turning behavior of robotic dolphins 一种新型机器人海豚表面站立转身行为的流体动力学研究

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2026-01-12 DOI: 10.1016/j.jfluidstructs.2026.104512

Ming Lei , Qingyuan Gai , Tongfu Zou , Dan Xia

To enhance the surface operation capabilities of traditional bionic underwater vehicles (BUVs) in, this study explored the feasibility of dolphins performing cross-medium standing-and-turning (SAT) behavior on the water surface from a hydrodynamics perspective. A physical model and computational model of the robotic dolphin’s surface SAT behavior were established. After numerous attempts, the surface SAT behavior of the robotic dolphin was successfully replicated through coordinated movements of the body, caudal fin, and pectoral fins, and the quantitative relationship between controllable parameters and hydrodynamic performance was investigated. By combining data analysis and flow field distribution patterns, the underlying physical mechanisms of the robotic dolphin’s surface SAT behavior were revealed. The results indicate that the turning trajectory of SAT behavior exhibits a circular characteristic, and the turning radius can be adjusted by modifying the kinematic parameters. Additionally, when the movement parameters of the body and caudal fin are fixed, and the phase difference between the two pectoral fins is T/2, the robotic dolphin achieves optimal turning maneuverability, with a maximum turning speed of 1.69 rad/s and a turning efficiency of up to 45.5%. Notably, by optimizing kinematic parameters, the robotic dolphin achieves cross-medium in-situ turning with exceptionally high maneuverability, which is indeed a very valuable discovery. The findings provide a cross-medium fluid dynamics explanation for the development of BUVs with dual underwater/surface operating capabilities.

为了提高传统仿生水下航行器（buv）的水面操作能力，本研究从水动力学角度探讨了海豚在水面上进行跨介质站立转向（SAT）行为的可行性。建立了机械海豚表面SAT行为的物理模型和计算模型。经过多次尝试，通过身体、尾鳍和胸鳍的协调运动，成功复制了机器海豚的表面SAT行为，并研究了可控参数与水动力性能之间的定量关系。通过数据分析和流场分布模式相结合，揭示了机器海豚表面SAT行为的潜在物理机制。结果表明，SAT行为的转弯轨迹呈现圆形特征，并且可以通过改变运动学参数来调节转弯半径。另外，当身体和尾鳍运动参数固定，胸鳍相位差为T/2时，机器海豚的转弯机动性达到最佳，最大转弯速度为1.69 rad/s，转弯效率高达45.5%。值得注意的是，通过优化运动学参数，机器人海豚实现了跨介质原地转弯，具有极高的机动性，这确实是一个非常有价值的发现。这些发现为具有水下/水面双重操作能力的buv的发展提供了跨介质流体动力学解释。

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引用次数: 0

Vortex-induced vibration dynamics of a splitter beam behind a cylinder in shear-thinning or shear-thickening non-Newtonian fluids 剪切变薄或变厚的非牛顿流体中圆柱后分离器梁的涡激振动动力学

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2026-01-12 DOI: 10.1016/j.jfluidstructs.2026.104513

Hao Liu , Shaowei Wang , Moli Zhao , Peiyuan Wang , Shuai Liu , Yegao Qu

The vortex-induced vibration (VIV) dynamics of a flexible splitter beam interacting with the laminar wake flow of a circular cylinder in shear-thinning and shear-thickening fluids are investigated using a partitioned nonlinear fluid-structure interaction simulation. The flow field is modeled within an Arbitrary Lagrangian-Eulerian (ALE) framework based on the finite volume method. To capture the beam's large deformations, Reddy's higher-order shear deformation theory is employed in conjunction with von Kármán strain formulations. After validating the present method, a comprehensive analysis is conducted to investigate the effects of the following parameters, including beam characteristic length (L/H = 10 and 15), inflow velocity (0.5 m/s ≤ U_r ≤ 3 m/s), power-law index (0.6 ≤ n ≤ 1.4) and time constant (0.2 s ≤

λ

≤ 4 s) on the VIV characteristics (including limit-cycle oscillation, vortex shedding pattern and viscosity distribution) are discussed. Several distinct deformation regimes of elastic beams are observed: first or second mode-like vibration regimes; standing or traveling wave deflection vibration regimes; the large amplitude traveling wave symmetry vibration regimes; and periodic or quasi-periodic dual-frequency vibration regimes. These different regimes result in variations in the wake vortex modes, specifically the '2S' (two single vortices of opposite sign) and '2P' (two pairs of vortices) modes. Key findings indicate that shear-thinning fluids lowers the onset point of VIV in comparison with Newtonian fluids, while shear-thickening fluids elevates it, suggesting a viscous damping effect. Additionally, shear-thinning fluids amplify vorticity intensity and contract the wake region, while shear-thickening fluids suppress vorticity generation and significantly elongate the wake. Moreover, a higher time constant in shear-thinning fluids amplifies vibrations by enhancing vorticity persistence and energy transfer. In shear-thickening fluids, however, it suppresses VIV by promoting viscosity-dominated damping.

采用分块非线性流固耦合仿真方法，研究了在剪切变薄和剪切增稠流体中柔性分流梁与圆柱层流尾流相互作用时的涡激振动动力学。基于有限体积法，在任意拉格朗日-欧拉框架内建立了流场模型。为了捕捉梁的大变形，Reddy的高阶剪切变形理论与von Kármán应变公式结合使用。在验证了该方法的基础上，综合分析了光束特征长度（L/H = 10和15）、入流速度（0.5 m/s≤Ur≤3m /s）、幂律指数（0.6≤n≤1.4）和时间常数（0.2 s≤λ≤4 s）等参数对涡激振荡特性（包括极限环振荡、涡落模式和粘度分布）的影响。观察到弹性梁的几种不同的变形状态：第一或第二模态振动状态；驻波或行波偏转振动机制；大振幅行波对称振动区；以及周期或准周期双频振动。这些不同的状态导致了尾流涡模式的变化，特别是“2S”（两个相反符号的单涡）和“2P”（两个对涡）模式。关键发现表明，与牛顿流体相比，剪切减薄流体降低了VIV的起始点，而剪切增稠流体则提高了VIV的起始点，表明存在粘性阻尼效应。此外，剪切减薄流体放大了涡度强度并收缩了尾迹区域，而剪切增厚流体抑制了涡度的产生并显著延长了尾迹。此外，剪切变薄流体中较高的时间常数通过增强涡度持久性和能量传递来放大振动。然而，在剪切增稠流体中，它通过促进粘度主导的阻尼来抑制VIV。

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引用次数: 0

Wave-current-floating body interactions: Experiments and modelling 波-流-浮体相互作用：实验和模型

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2026-01-11 DOI: 10.1016/j.jfluidstructs.2025.104498

Masoud Hayatdavoodi , Shuijin Li

The interaction of combined waves and current with floating bodies is studied by conducting laboratory experiments and by developing theoretical models. The laboratory experiments are conducted in a wave-current tank using two floating cylinders with circular and square waterplane areas. Both freely floating and moored conditions are considered. Two theoretical models are developed to study wave-body and wave-current-body interactions: one based on the computational fluid dynamics and the other following the linear wave-current diffraction theory using the Green function method. Results from these models are compared with laboratory measurements for a range of wave and wave-current conditions. The study analyses the effect of ambient current on the wave-induced motions of floating bodies and evaluates how well the models capture the wave-current-body interactions. Additionally, the effect of the square cylinder’s sharp edges on wave-current-body interactions is analysed in comparison to the circular cylinder, along with the models’ capability to capture these effects. It is observed that the presence of the current not only causes significant drift of the freely floating cylinders, but also affects their surge and pitch oscillations, while having no notable effect on heave motion. For the conditions considered, the linear theory based on the Green function method provides overall good predictions of the floating bodies’ responses at a significantly lower computational cost compared to the computational fluid dynamics model.

通过室内实验和建立理论模型，研究了波浪和水流与浮体的相互作用。实验在波浪流槽中进行，采用圆形和方形水面面积的两个浮柱。自由浮动和系泊条件都被考虑。建立了两个理论模型来研究波-体和波-流-体相互作用：一个基于计算流体力学，另一个基于格林函数方法的线性波-流衍射理论。这些模型的结果与一系列波浪和波流条件下的实验室测量结果进行了比较。本研究分析了环境电流对浮体波浪运动的影响，并评估了模型如何很好地捕捉波浪-流-体相互作用。此外，与圆形圆柱体相比，分析了方形圆柱体的尖锐边缘对波流体相互作用的影响，以及模型捕捉这些影响的能力。观察到，电流的存在不仅使自由漂浮的气缸产生明显的漂移，而且影响其喘振和俯仰振荡，而对升沉运动没有显著影响。对于所考虑的条件，基于格林函数方法的线性理论与计算流体动力学模型相比，以显著降低的计算成本提供了总体上较好的浮体响应预测。

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引用次数: 0

Dynamics of elongated microswimmers in a square-tube flow 方管流动中细长微游泳体的动力学

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2026-01-09 DOI: 10.1016/j.jfluidstructs.2025.104499

Yuxiang Ying, Geng Guan, Tongxiao Jiang, Amin Ullah, JianZhong Lin

Microswimmers exhibit remarkable dynamic properties in fluid environments, making them important for advancing the fields of fluid mechanics and biophysics. In this study, we extended the classical squirmer model to an ellipsoidal geometry and investigated its swimming behavior in a three-dimensional square-tube flow. The results were compared with those of a spherical microswimmer. By systematically varying key parameters, including the self-propulsion strength (α), swimming type factor (β), chirality factor (χ), and flow field Reynolds number (Re_m), we identified five distinct swimming modes: near-wall helical motion, near-center helical motion, steady linear motion, zigzag motion, and near-wall double-helical motion, in which the microswimmer exhibited two different swimming directions (upstream and downstream). The results show that chirality and geometric anisotropy significantly influenced the swimming behavior of the microswimmer. The formation of swimming modes is also related to the pressure distribution between the microswimmer and the wall. In addition, the swimming velocity and helical frequency of the microswimmer increased with increasing α or Re_m; however, the increase in the Reynolds number did not change the swimming mode of the microswimmer. Our research is expected to promote the understanding of the motion characteristics of active matter in dynamic flows and provide valuable insights into the design of efficient and controllable artificial microswimmers for biomedical and environmental applications.

微游泳者在流体环境中表现出显著的动态特性，对推进流体力学和生物物理学领域具有重要意义。在本研究中，我们将经典的蠕动模型扩展到椭球体，并研究了它在三维方管流中的游动行为。结果与球形微游泳者的结果进行了比较。通过系统地改变自推进强度（α）、游泳类型因子（β）、手性因子（χ）和流场雷诺数（Rem）等关键参数，确定了微游泳者的五种不同的游泳模式：近壁螺旋运动、近中心螺旋运动、稳定直线运动、之字形运动和近壁双螺旋运动，在这些模式下微游泳者表现出两种不同的游泳方向（上游和下游）。结果表明，手性和几何各向异性对微游泳者的游泳行为有显著影响。游泳模式的形成还与微游泳者与壁面之间的压力分布有关。此外，微游泳者的游泳速度和螺旋频率随α或Rem的增加而增加；然而，雷诺数的增加并没有改变微游泳者的游泳方式。我们的研究有望促进对动态流动中活性物质运动特性的理解，并为生物医学和环境应用中高效可控的人工微游泳者的设计提供有价值的见解。

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引用次数: 0

Impact of baffle flexibility on sloshing mitigation: A parametric study using partitioned two-way fluid-structure interaction 挡板灵活性对晃动缓解的影响：使用分区双向流固相互作用的参数化研究

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2026-01-08 DOI: 10.1016/j.jfluidstructs.2025.104500

Cristiano Biagioli, Francesco Serraino, Valerio Belardi, Francesco Vivio

This study investigates liquid sloshing in a rectangular tank equipped with horizontal flexible baffles to understand their influence on sloshing mitigation and intricate fluid-structure interaction (FSI) phenomena. A two-way coupled FSI model was developed using the Finite Element Method (FEM) for structural analysis and Finite Volume Method (FVM) with the Volume Of Fluid (VOF) formulation for fluid dynamics, employing a partitioned coupling strategy. Numerical decay tests explored dynamic behavior by varying baffle Young’s modulus and submergence levels. Enstrophy evolution was investigated as a robust indicator for quantifying energy dissipation associated with vortex dynamics, and a reduced-order acoustic-structural model was benchmarked as a tool for predicting fundamental frequency shifts. The FSI simulation methodology was validated against experimental results from previous literature, showing close agreement.

Key outcomes reveal that baffle stiffness critically governs system response, with appropriate flexibility significantly enhancing damping performance. For submerged baffles, increasing flexibility led to optimal damping driven by maximal vortex-induced energy loss. Conversely, shallow baffles showed superior damping with rigid configurations, primarily due to pressure drag rather than vortex dynamics. While initial conditions introduced transient nonlinearities with flexible baffles, overall trends for damping and frequency remained consistent. The simplified frequency-prediction model was reliable for practical flexibility ranges, but less accurate for extreme flexibility. Overall, this work deepens understanding of how baffle characteristics influence slosh mitigation, offering valuable guidance for anti-sloshing device engineering.

本文研究了装有水平柔性挡板的矩形槽内的液体晃动，以了解其对晃动缓解和复杂的流固耦合现象的影响。采用分区耦合策略，采用有限元法（FEM）进行结构分析，采用有限体积法（FVM）与流体体积（VOF）公式进行流体动力学分析，建立了双向耦合FSI模型。数值衰减试验通过改变挡板的杨氏模量和淹没水平来探索动态行为。研究了熵演化作为量化与涡旋动力学相关的能量耗散的稳健指标，并将降阶声学结构模型作为预测基频移的基准工具。FSI模拟方法与先前文献的实验结果进行了验证，显示出密切的一致性。关键结果表明，挡板刚度对系统响应起关键作用，适当的柔性可以显著提高阻尼性能。对于水下挡板，增加的灵活性导致最大的涡流引起的能量损失驱动的最佳阻尼。相反，在刚性配置下，浅挡板表现出更好的阻尼，主要是由于压力阻力而不是涡流动力学。虽然初始条件引入了带有柔性挡板的瞬态非线性，但阻尼和频率的总体趋势保持一致。简化的频率预测模型在实际柔性范围内是可靠的，但在极端柔性范围内精度较低。总的来说，这项工作加深了对挡板特性如何影响晃动缓解的理解，为防晃动装置工程提供了有价值的指导。

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引用次数: 0

Direct measurements of aerodynamic and inertial contributions to unsteady forces on non-rigid objects in a flow 直接测量流动中非刚性物体对非定常力的气动和惯性贡献

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2026-01-06 DOI: 10.1016/j.jfluidstructs.2025.104495

F. Paillé , Y. Haffner , C. Sicot

A method is presented to separate inertial and aerodynamic contributions to the forces measured in experiments on a non-rigid object in a flow. In particular, it can be used to remove spurious inertial contributions on aerodynamic loads measured with a balance. The method builds on a multiple-input/multiple-output framework and uses conditional spectral analysis in order to provide frequency response functions, or alternatively impulse response functions, to link the inputs quantifying inertia on the object (any kind of acceleration measurements) and the unknown aerodynamic forces on the object to the outputs quantifying total forces on the object (aerodynamic balance or any kind of force measurements). The method provides an efficient way of separating inertial and aerodynamic force contributions on objects in a flow from relatively few acceleration measurements and total force measurements.

This methodology is assessed on a wall-mounted cylinder in a turbulent boundary layer having two principal bending modes contributing to important inertial forces. It performs well to separate the inertial force contributions of the different bending modes from the pure aerodynamic force contributions which align very closely to the reference aerodynamic pressure forces. Especially, the method allows to separate unambiguously the inertial and aerodynamic force contributions even when structural and aerodynamic resonances have matching frequencies. A second test-case of a model of high-rise building with more complex structural dynamics and less effort put in manufacturing is presented. The method performs also well but with a bit more discrepancies to the reference aerodynamic pressure forces. In this case, part of the inertial forces are not correctly accounted for depending on the relevance of the location and number of acceleration measurements on the object, and on the complexity of the structural dynamics of the object. Leads are provided and discussed to tackle these relative limitations.

提出了一种分离非刚性物体在流动中所测力的惯性和气动贡献的方法。特别是，它可以用来消除虚假的惯性贡献气动载荷测量与平衡。该方法建立在多输入/多输出框架上，并使用条件谱分析，以提供频率响应函数或脉冲响应函数，将量化物体上的惯性的输入（任何类型的加速度测量）和物体上未知的空气动力与量化物体上的总力的输出（空气动力平衡或任何类型的力测量）联系起来。该方法提供了一种有效的方法，从相对较少的加速度测量和总力测量中分离出流中物体的惯性力和气动力。该方法在紊流边界层中的壁挂式圆柱体上进行了评估，该圆柱体具有两种主要的弯曲模式，可以产生重要的惯性力。它可以很好地将不同弯曲模式的惯性力贡献与与参考气动压力非常接近的纯气动力贡献分离开来。特别是，即使结构和气动共振具有匹配的频率，该方法也可以明确地分离惯性和气动力贡献。给出了结构动力学更复杂、制造成本更低的高层建筑模型的第二个测试案例。该方法执行也很好，但与参考空气动力压力有一点差异。在这种情况下，部分惯性力不能正确计算，这取决于物体上加速度测量的位置和次数的相关性，以及物体结构动力学的复杂性。提供并讨论了解决这些相对限制的方法。

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引用次数: 0

Mechanism and regulation of silicone oil fluid volume on the stick-slip behavior of PDMS sponges 硅油液量对PDMS海绵粘滑行为的影响机理及调控

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2026-01-06 DOI: 10.1016/j.jfluidstructs.2026.104501

Rongxin Chen , Hui Zhong , Bozhan Hai , Qingrui Song , Wei Zhang , Guofu Lian

Stick-slip behavior during friction is a critical factor contributing to the degradation of PDMS material performance. To mitigate this phenomenon, this study investigates the effects of silicone oil with varying parameters on the frictional and mechanical properties of PDMS sponges. Friction experiments were conducted by introducing silicone oil fluids, and the influence of silicone oil on the friction coefficient and stick-slip behavior was analyzed. Additionally, the nominal modulus of elasticity of PDMS sponges was measured to explore the interrelationship among elasticity, friction coefficient, and stick-slip behavior. The results demonstrate that as the viscosity of silicone oil increases, the stick-slip time (∆t) of PDMS sponge decreases, the difference between static and kinetic friction coefficients (∆μ) diminishes, and the modulus of elasticity of PDMS sponge increases. High-viscosity silicone oil effectively reduces both stick-slip behavior and the friction coefficient of PDMS sponge. At constant viscosity, an increase in the volume of silicone oil leads to a reduction in the friction coefficient of PDMS sponge but simultaneously enhances the likelihood of stick-slip behavior while decreasing the nominal modulus of elasticity. By controlling the liquid parameters of silicone oil, the friction coefficient and stick-slip behavior of PDMS sponges can be modulated. This study explores the formation mechanism of the viscous-slip behavior and proposes a method to control the viscous-slip behavior by different liquids. This can provide theoretical guidance for the regulation of viscous-slip behavior in other polymers.

摩擦过程中的粘滑行为是导致PDMS材料性能退化的关键因素。为了缓解这一现象，本研究研究了硅油不同参数对PDMS海绵摩擦和力学性能的影响。通过引入硅油流体进行摩擦实验，分析了硅油对摩擦系数和粘滑性能的影响。此外，测量了PDMS海绵的名义弹性模量，以探索弹性，摩擦系数和粘滑行为之间的相互关系。结果表明：随着硅油粘度的增加，PDMS海绵的粘滑时间（∆t）减小，静摩擦系数与动摩擦系数之差（∆μ）减小，海绵的弹性模量增大；高粘度硅油能有效降低PDMS海绵的粘滑性能和摩擦系数。在一定粘度下，硅油体积的增加导致PDMS海绵的摩擦系数降低，但同时增加了粘滑行为的可能性，同时降低了公称弹性模量。通过控制硅油的液体参数，可以调节PDMS海绵的摩擦系数和粘滑性能。本研究探讨了粘滑行为的形成机理，并提出了不同液体控制粘滑行为的方法。这可以为其它聚合物的粘滑行为调控提供理论指导。

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引用次数: 0

Stable fluid-rigid body interaction algorithm using the direct-forcing immersed boundary method (DF-IBM) 基于直接强迫浸入边界法的稳定流体-刚体相互作用算法（DF-IBM）

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2026-01-05 DOI: 10.1016/j.jfluidstructs.2025.104496

Elias Farah , Abdellatif Ouahsine , Patrick G. Verdin , Badr Kaoui

The direct-forcing immersed boundary method (DF-IBM) algorithm previously developed by the authors is extended by coupling the Navier-Stokes equations with the Newton-Euler equations for rigid body dynamics within the DF-IBM framework. This coupling broadens the applicability of the previous development, from stationary or prescribed motion to flow-induced (free) motion cases. To address fluid-rigid body interactions under a partitioned approach, an implicit coupling algorithm is developed to handle strongly coupled interface conditions. Stability and convergence issues, particularly stemming from critical solid-fluid density ratios and from the rigid body approximation of internal mass effects in rotational dynamics, are mitigated using a fixed relaxation technique for the rigid body kinematics to ensure numerical robustness. Additionally, the proposed algorithm leverages the previously developed DF-IBM formulation and the predictor-corrector strategy of the pressure implicit with splitting of operators (PISO) algorithm by omitting the momentum predictor step and the costly corrector loops from the implicit iterations. The method is validated against several benchmark cases, demonstrating robustness, stability, and efficiency in capturing complex fluid-rigid body interactions across a range of challenging scenarios.

通过在DF-IBM框架内将刚体动力学的Navier-Stokes方程与Newton-Euler方程耦合，对作者先前开发的直接强迫浸入边界法（DF-IBM）算法进行了扩展。这种耦合扩大了先前开发的适用性，从固定或规定运动到流诱导（自由）运动情况。为了在分区方法下处理流体-刚体相互作用，提出了一种隐式耦合算法来处理强耦合界面条件。稳定性和收敛问题，特别是源于临界固流密度比和旋转动力学中内部质量效应的刚体近似，使用刚体运动学的固定松弛技术来缓解，以确保数值稳健性。此外，该算法利用先前开发的DF-IBM公式和压力隐式算子分裂（PISO）算法的预测-校正策略，省去了隐式迭代中的动量预测步骤和代价高昂的校正循环。该方法通过几个基准案例进行了验证，证明了在一系列具有挑战性的场景中捕获复杂流体-刚体相互作用的鲁棒性、稳定性和效率。

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引用次数: 0