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

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

Control of the channel flow past a cylinder by a piezo-actuated flexible splitter plate 通过一个压电驱动的柔性分流板来控制通道流过圆柱体

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-12-23 DOI: 10.1016/j.jfluidstructs.2025.104490

Simone Cruciani , Franco Auteri , Michel Fournié

We study the numerical stabilization around an unstable steady solution of a typical fluid-structure interaction problem constituted by a circular cylinder with a flexible splitter plate (Turek and Hron, 2006) actuated by piezoelectric devices and immersed in a fully developed, laminar channel flow. We define a linear feedback control that can locally stabilize the fully coupled nonlinear system. The feedback is based on a spectral decomposition of a non-standard Differential Algebraic Equation resulting from a monolithic Arbitrary Lagrangian Eulerian Finite Element formulation where a simple model of the piezoelectric patches is considered. By projecting the full system on its unstable subspace, a Reduced Order Model is defined. The design of the controlled system exploits the computation of the unstable direct and adjoint subspaces to identify the number and distribution of the patches on the beam. Moreover, the feasibility of such a controller for a real application is assessed by looking at the saturation limit of the control input. This paper is an extension of the methodology presented in Airiau et al. (2017) and Fournié et al. (2019) to control the Navier-Stokes equations to a fluid-structure model actuated by macro-fiber composites. To our knowledge, such active controls are original and the numerical tests presented validate their promising potential.

我们研究了一个典型的流固相互作用问题的不稳定定常解周围的数值稳定化问题，该问题由一个由压电装置驱动的带有柔性分裂板的圆柱体组成（Turek和Hron， 2006），并浸没在一个完全发育的层流通道中。定义了一种能局部稳定全耦合非线性系统的线性反馈控制。反馈基于非标准微分代数方程的谱分解，该方程由单一的任意拉格朗日欧拉有限元公式产生，其中考虑了压电片的简单模型。通过将整个系统投影到不稳定子空间上，定义了一个降阶模型。控制系统的设计利用不稳定直接子空间和伴随子空间的计算来识别光束上贴片的数量和分布。此外，通过观察控制输入的饱和极限来评估这种控制器在实际应用中的可行性。本文是Airiau等人（2017）和fourni等人（2019）提出的方法的扩展，将Navier-Stokes方程控制为由宏纤维复合材料驱动的流体结构模型。据我们所知，这种主动控制是原创的，所提出的数值试验证实了它们的良好潜力。

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引用次数: 0

Hydrodynamic radiation analysis of bottom-mounted cylinder arrays in two-layer fluids 底置圆柱阵列在两层流体中的水动力辐射分析

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-12-22 DOI: 10.1016/j.jfluidstructs.2025.104494

Zhen Xue , Chao Wang , Fajun Yu , Shaoyu Zhong

This study advances radiation hydrodynamics for cylindrical arrays in two-layer fluids, addressing critical challenges inherent to density-stratified systems. While existing methodologies effectively characterize wave interactions in uniform-density environments, the coupled surface-interface boundary conditions in stratified flows introduce three fundamental complexities: modal coupling between surface and internal waves governed by density (

γ = ρ_{1} / ρ_{2}

) and depth (

h_{1} / h_{2}

) ratios, non-negligible evanescent modes in radiation processes, and nonlinear parametric dependencies of radiation forces on stratification parameters and geometric factors such as radius-to-depth ratio (

a / h

) and spatial arrangement. To resolve these challenges, a generalized hydrodynamic model is developed by integrating a modified stratified eigenfunction method with a multi-cylinder interference theory. This framework enables systematic quantification of hydrodynamic coefficients under both global and relative radiation motions, revealing the influence of geometric configurations, stratification parameters, and motion modalities. Parametric studies demonstrate the critical regulatory role of density ratio and interface elevation on radiation, particularly under internal wave dominance, while identifying phase-dependent amplification or attenuation effects of complex motion modes on added mass and damping coefficients in two-layer systems. Validated against classical homogeneous-fluid and stratified single-cylinder solutions, the model provides design insights for mitigating hydrodynamic loads in stratified marine environments. The work establishes a unified framework for predicting multi-body interactions in density-stratified flows, connecting homogeneous fluid theory with practical maritime engineering applications.

该研究推进了两层流体中圆柱形阵列的辐射流体动力学，解决了密度分层系统固有的关键挑战。虽然现有的方法可以有效地表征均匀密度环境中的波相互作用，但分层流动中的耦合表面界面边界条件引入了三个基本的复杂性：表面波和内波之间的模态耦合受密度（γ=ρ1/ρ2）和深度（h1/h2）比、辐射过程中不可忽略的消失模态以及辐射力对分层参数、半径/深度比（a/h）和空间排列等几何因素的非线性参数依赖性的影响。为了解决这些问题，将改进的分层特征函数方法与多柱干涉理论相结合，建立了广义水动力模型。该框架能够系统地量化整体和相对辐射运动下的水动力系数，揭示几何构型、分层参数和运动模式的影响。参数研究表明，密度比和界面高程对辐射的关键调节作用，特别是在内波优势下，同时确定了复杂运动模式对两层体系中附加质量和阻尼系数的相位依赖放大或衰减效应。该模型经过了经典的均质流体和分层单缸方案的验证，为减轻分层海洋环境中的水动力载荷提供了设计见解。这项工作建立了一个统一的框架，用于预测密度分层流动中的多体相互作用，将均质流体理论与实际海洋工程应用联系起来。

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引用次数: 0

Torsional motion study on the aerodynamic instability of solar tracking systems 太阳能跟踪系统气动不稳定性的扭转运动研究

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-12-22 DOI: 10.1016/j.jfluidstructs.2025.104492

Kanghui Zheng , Yukun Feng , Zuogang Chen , Yi Dai

In this study, the torsional motion induced by the aerodynamic instability in solar tracking systems was investigated through field modal testing, wind tunnel experiments, and computational fluid dynamics (CFD) simulations. First, modal testing was conducted on a full-scale solar tracking system to obtain the system's natural frequencies and damping ratios, which were used as input data for subsequent calculations. Second, aerodynamic instability experiments of the solar tracking system at the model scale were carried out, and the variations of the torsional angles with the wind speed at different installation angles were obtained. CFD simulations were also conducted under the same conditions, and the reliability of the CFD model was verified by comparing the simulation results with the experimental data. Third, CFD simulations were carried out on a full-scale solar tracking system to study the effects of two key parameters, the wind speed and the installation angle, on the aerodynamic instability. Critical wind speed curves for aerodynamic instability at different installation angles were obtained, and the flow mechanisms of the "torsional divergence" and "vortex lock-in" phenomena were summarized by analyzing the details of the flow field. Finally, the additional damping ratio's effect on suppressing torsional motion was evaluated. The results showed that the numerical model successfully simulated the entire process of the system's torsional divergence, with dynamic response characteristics that matched well with the experimental observations. For the full-scale model, at 0° installation angles, when the wind speed was below 44 m/s, flat-shaped vortex systems remained attached to the surface of the system. However, when the wind speed reached 45 m/s, alternating vortex shedding occurred on the upper and lower sides of the leading edge of the photovoltaic panel, intensifying the torsional motion of the solar tracking system. Continuous excitation ultimately led to an amplitude jump from within 10° to approximately 80°, resulting in the torsional divergence phenomenon and significantly increasing the risk of structural damage. When the installation angle was between 20° and 50°, vortex systems formed on the leeward side of the solar tracking system and alternately shed at the leading and trailing edges, creating the vortex lock-in phenomenon. This caused the vortex shedding frequency to remain almost unchanged within a certain wind speed range. Additionally, increasing the additional damping ratio from 0 % to 10 % had almost no effect on the critical wind speed at a 0° installation angle. For larger installation angles, increasing the damping ratio reduced the amplitude of torsional motion, thereby effectively increasing the critical wind speed. The results of this study provide a reference for the design and optimization of solar tracking systems, reducing the risk of structural damage to the system.

通过现场模态试验、风洞试验和计算流体动力学（CFD）模拟，研究了太阳跟踪系统中气动不稳定性引起的扭转运动。首先，在全尺寸太阳能跟踪系统上进行模态试验，获得系统的固有频率和阻尼比，作为后续计算的输入数据。其次，在模型尺度下对太阳能跟踪系统进行了气动不稳定性实验，得到了不同安装角度下扭转角随风速的变化规律。在相同条件下进行了CFD仿真，通过仿真结果与实验数据的对比，验证了CFD模型的可靠性。第三，对全尺寸太阳能跟踪系统进行CFD仿真，研究风速和安装角两个关键参数对系统气动不稳定性的影响。得到了不同安装角度下气动失稳临界风速曲线，并通过对流场细节的分析，总结了“扭散”和“涡锁”现象的流动机理。最后，评价了附加阻尼比对扭转运动的抑制作用。结果表明，该数值模型成功地模拟了系统扭转发散的全过程，其动态响应特性与实验观测值吻合较好。对于全尺寸模型，在0°安装角下，风速低于44 m/s时，平面涡系统仍附着在系统表面。然而，当风速达到45 m/s时，光伏板前缘上下两侧发生交替涡脱落，加剧了太阳能跟踪系统的扭转运动。连续激励最终导致振幅从10°以内跃升至约80°，产生扭转发散现象，显著增加了结构损伤的风险。当安装角在20°~ 50°之间时，在太阳跟踪系统的背风侧形成涡系，并在前后缘交替脱落，形成涡锁现象。这使得旋涡脱落频率在一定风速范围内几乎保持不变。此外，将附加阻尼比从0%增加到10%对0°安装角下的临界风速几乎没有影响。对于较大的安装角度，增大阻尼比可以减小扭转运动的幅值，从而有效地提高临界风速。研究结果为太阳能跟踪系统的设计和优化提供了参考，降低了系统结构损坏的风险。

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引用次数: 0

Numerical simulation of band gap characteristics of periodic curved stiffened plates considering fluid-structure interaction 考虑流固耦合的周期弯曲加筋板带隙特性数值模拟

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-12-20 DOI: 10.1016/j.jfluidstructs.2025.104487

H.A. Ma , Z.X. Xia , S.T. Gu , H.J. Liu , Y. Cong , H.P. Yin

Curved stiffened plates are frequently subjected to vibration challenges during their application in marine and underwater engineering structures. Traditional vibration mitigation strategies, such as increasing structural stiffness or incorporating high-damping materials, often lead to increased design complexity. In this study, a novel vibration reduction approach is proposed by designing periodic structures with appropriately arranged curved stiffeners. This approach leverages the unique band gap characteristics of periodic structures for vibration attenuation. A numerical framework is established for band gap analysis of arbitrarily curved stiffened plates, incorporating fluid-structure interaction (FSI) effects. Specifically, the constitutive model of the curved stiffened plate is derived using the Mindlin plate theory and Timoshenko beam theory. The fluid-structure interaction is modeled via the added mass method, and periodic boundary conditions are applied to both the plate and the fluid domains based on Bloch’s theorem. Numerical validation confirms the accuracy of the modal analysis for curved stiffened plates. The importance of properly arranging curved stiffeners was demonstrated through time-domain dynamic analyses of several finite structures, which also confirmed the effectiveness of the band gap. The influence of the fluid environment on the system’s band gap characteristics was thoroughly examined. Particular attention was given to how the amplitude, wavelength, and structural parameters of sinusoidal stiffeners affect the band gap, as well as the anisotropic propagation of elastic waves in sinusoidal stiffened plates. The results indicate that specific stiffener designs play a critical role in tuning band gap properties and enhancing structural vibration performance, offering valuable insights for vibration reduction in fluid-structure coupled curved stiffened plate applications.

弯曲加筋板在海洋和水下工程结构中经常受到振动的挑战。传统的减振策略，如增加结构刚度或采用高阻尼材料，通常会导致设计复杂性的增加。在本研究中，提出了一种新的减振方法，即设计具有合理布置的弯曲加强筋的周期结构。这种方法利用周期结构独特的带隙特性进行振动衰减。建立了考虑流固耦合效应的任意弯曲加筋板带隙分析的数值框架。具体而言，采用Mindlin板理论和Timoshenko梁理论推导了弯曲加筋板的本构模型。采用附加质量法对流固耦合进行了建模，并基于Bloch定理对板域和流体域分别施加了周期边界条件。数值验证验证了弯曲加筋板模态分析的准确性。通过对几个有限结构的时域动力分析，论证了合理布置弯曲加强筋的重要性，也证实了带隙的有效性。研究了流体环境对系统带隙特性的影响。研究了正弦加劲板的振幅、波长和结构参数对带隙的影响，以及弹性波在正弦加劲板中的各向异性传播。结果表明，特定的加筋设计在调节带隙特性和提高结构振动性能方面起着至关重要的作用，为流固耦合弯曲加筋板的减振应用提供了有价值的见解。

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引用次数: 0

A new dynamical model for cantilevered pipe conveying fluid based on fifth-order Taylor expansion 基于五阶泰勒展开的悬挑管道输送流体动力学模型

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-12-18 DOI: 10.1016/j.jfluidstructs.2025.104489

Hao Lv , Tianli Jiang , Wei Chen , Huliang Dai , Lin Wang

Fluid-conveying pipes are widely used across various engineering fields, including aerospace, marine, nuclear and mechanical systems. Establishing a theoretical model that balances high accuracy with computational efficiency is essential for investigating the nonlinear dynamical behavior of such systems. In this study, a new fifth-order Taylor expansion model is proposed to improve the representation of the bending curvature compared to the conventional third-order approximations. By applying the axial inextensibility condition, the kinematic relationship between transverse and axial displacements of the deformed pipe is obtained. Using Hamilton’s principle, the nonlinear governing equation of motion for a cantilevered fluid-conveying pipe is derived within the fifth-order Taylor expansion framework. The resulting partial differential equation is spatially discretized via the Galerkin method and numerically solved using the fourth-order Runge-Kutta algorithm to analyze the nonlinear dynamic responses. Numerical calculations are conducted to compare the computational accuracy and efficiency of the proposed fifth-order Taylor expansion model against both the traditional third-order model and the geometrically exact model. In addition, the influence of two key parameters—mass ratio and gravity parameter—on the dynamical behavior of the pipe is further examined under both high and low flow velocities. Results show that the fifth-order Taylor expansion model offers improved accuracy and wider applicability over the third-order model.

流体输送管道广泛应用于各个工程领域，包括航空航天，船舶，核和机械系统。建立一个平衡高精度和计算效率的理论模型是研究此类系统非线性动力学行为的必要条件。本文提出了一种新的五阶Taylor展开模型，与传统的三阶近似相比，可以更好地表示弯曲曲率。应用轴向不可拓性条件，得到了变形管道横向位移与轴向位移的运动关系。利用Hamilton原理，在五阶Taylor展开框架下推导了悬臂式输液管道的非线性运动控制方程。利用伽辽金方法对得到的偏微分方程进行空间离散，利用四阶龙格-库塔算法进行数值求解，分析非线性动力响应。通过数值计算比较了所提出的五阶Taylor展开模型与传统三阶模型和几何精确模型的计算精度和效率。此外，还进一步研究了高、低流速下质量比和重力参数对管道动力性能的影响。结果表明，与三阶模型相比，五阶Taylor展开模型具有更高的精度和更广泛的适用性。

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引用次数: 0

Aeroelastic response of a three-dimensional square cylinder to large-scale sinusoidal gusts with acoustic disturbances 三维方柱体对带声干扰的大尺度正弦阵风的气动弹性响应

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-12-17 DOI: 10.1016/j.jfluidstructs.2025.104491

Lixuan Zhao , Qiusheng Li

Despite extensive studies on the aerodynamics and aeroelastic behavior of three-dimensional (3D) square cylinders under turbulent and smooth flows, limited attention has been paid to the effects of large-scale sinusoidal gusts. In particular, the influence of such unsteady inflow conditions on wind-induced vibration characteristics of 3D aeroelastic bluff bodies remains underexplored. This study experimentally investigates the influence of streamwise sinusoidal oscillating flows (SSOFs) on the wind-induced vibrations of a 3D aeroelastic square cylinder, focusing on the instability phenomena of vortex-induced vibration (VIV) and transverse galloping. Wind tunnel testing is conducted to measure the along-wind and across-wind displacement responses under various SSOF conditions, supplemented by wake velocity measurements. To further explore the sound-gust coupling effects on fluid-structure interactions, sinusoidal sound disturbance is also considered. The results reveal that SSOFs significantly enhance along-wind responses while attenuating across-wind vibrations, with the impact depending on gust amplitude and frequency. Vortex shedding in the wake is notably suppressed, especially within the VIV regime. Besides, sound resonant with the cylinder amplifies oscillations and fosters instability, while resonance with the gust tends to suppress them. These findings offer new insights into the aeroelastic responses of bluff bodies in complex unsteady flow environments and highlight the potential influence of sound-flow coupling on structural performance.

尽管对三维（3D）方形圆柱体在湍流和光滑流动下的空气动力学和气动弹性行为进行了广泛的研究，但对大规模正弦阵风的影响关注有限。特别是，这种非定常入流条件对三维气动弹性钝体风致振动特性的影响尚未得到充分研究。实验研究了顺流正弦振荡流（SSOFs）对三维气动弹性方柱体风致振动的影响，重点研究了涡激振动（VIV）和横向驰动的不稳定性现象。通过风洞试验测量了不同SSOF条件下的顺风和横风位移响应，并辅以尾迹速度测量。为了进一步探讨声-阵风耦合对流固耦合的影响，还考虑了正弦声扰动。结果表明，SSOFs显著增强了顺风响应，同时减弱了横风振动，其影响与阵风振幅和频率有关。尾流中的旋涡脱落明显受到抑制，特别是在涡激气流中。此外，与圆柱体共振的声音放大了振荡，助长了不稳定，而与阵风共振往往会抑制振荡。这些发现为研究复杂非定常流动环境下钝体的气动弹性响应提供了新的见解，并突出了声流耦合对结构性能的潜在影响。

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引用次数: 0

Flow dynamics around mesh wrapped wall-mounted circular cylinders 围绕网格缠绕壁挂式圆柱的流动动力学

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-12-17 DOI: 10.1016/j.jfluidstructs.2025.104488

Abhinav Thakurta , Priscilla Williams , Ram Balachandar

This study experimentally investigates the flow around emergent, wall-mounted circular cylinders wrapped in a nine-start bidirectional helical mesh. The motivation stems from the need to reduce local scour in hydraulic and offshore structures, where conventional porous coatings are prone to sediment clogging. The proposed bidirectional mesh acts as a passive flow control method to alter wake dynamics and also potentially enhance heat transfer in pin fin applications. Three mesh configurations with a fixed pitch of 2d and varying heights, 0.01d, 0.02d, and 0.04d (where d is the cylinder diameter), are evaluated. Experiments were conducted at a Reynolds number of 14,500 (based on cylinder diameter), using particle image velocimetry (PIV) to capture detailed velocity fields and analyze flow structures. At lower mesh heights, only minor deviations from the baseline (bare cylinder) flow are observed. However, the 0.04d mesh notably reduces wake mean velocity, elongates the recirculation region, and distorts the near-bed wake structure. Instantaneous velocity fields and probability density function analysis reveal enhanced flapping of the separated shear layers at mid-wake for the 0.04d case. Two-point correlation analysis shows that this configuration increases near-bed coherent structure size, while smaller mesh heights reduce spatial coherence. Upstream of the cylinder, the flow exhibits bimodal unsteadiness, marked by intermittent transitions between back-flow and zero-flow modes, indicating that the horseshoe vortex system is sensitive to mesh height. Reynolds stress distributions at the cylinder-bed junction further highlight that the 0.04d mesh represents a threshold, beyond which significant changes in both upstream junction flow and downstream wake behaviour become apparent.

本研究通过实验研究了包裹在九启动双向螺旋网格中的紧急壁挂式圆柱体周围的流动。其动机是为了减少水力和海上结构的局部冲刷，在这些地方，传统的多孔涂层容易被沉积物堵塞。所提出的双向网格作为一种被动的流动控制方法来改变尾迹动力学，也有可能增强针鳍应用中的传热。评估了三种具有固定间距2d和变化高度0.01d， 0.02 2d和0.04d（其中d为圆柱体直径）的网格配置。实验在雷诺数为14500（基于圆柱体直径）的条件下，采用粒子图像测速技术（PIV）捕获了详细的速度场并分析了流动结构。在较低的网格高度，只有轻微偏离基线（裸圆柱）流动被观察到。然而，0.04d网格明显降低了尾流平均速度，延长了再循环区域，并扭曲了近床尾流结构。瞬时速度场和概率密度函数分析表明，在0.04d的情况下，分离剪切层在中尾流处的扑动增强。两点相关分析表明，该配置增加了近层相干结构尺寸，而较小的网格高度则降低了空间相干性。在柱体上游，水流表现为双峰非定常，在回流和零流模式之间间歇性转换，表明马蹄形涡系统对网格高度敏感。圆柱床结合部的雷诺应力分布进一步强调，0.04d网格代表了一个阈值，超过这个阈值，上游结合部流动和下游尾迹行为的显著变化就会变得明显。

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