Journal of Fluids and Structures最新文献_第7页

Flow-induced noise of circular finite wall-mounted cylinders 壁挂式有限圆柱的流动噪声

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-10-17 DOI: 10.1016/j.jfluidstructs.2025.104437

Wenyu Chen , Con Doolan , Danielle Moreau

A finite-length circular cylinder mounted to a wall serves as a simplified model for bluff bodies encountering flow, with a wide range of relevant applications, including aircraft landing gear, automobile appendages, and wind turbine masts. In the present study, finite wall-mounted circular cylinders with different spanwise aspect ratios (

A R = L / D

where

L

is the length of the cylinder and

D

is its diameter) of 3.2, 6.5, 12.9 and 22.6 are examined at a Reynolds number of

R e = 12, 000

based on the cylinder diameter. The incoming boundary layer thickness on the wall to which the cylinder is mounted is

δ / D = 0.83

. Large Eddy Simulation (LES) is employed to simulate the turbulent flow, and the Ffowcs Williams–Hawkings equations are solved simultaneously to predict the far-field noise. The acoustic spectrum of the circular FWMCs is characterized by tonal peaks for aspect ratios

A R

= 3.2, 12.9, and 22.6 in which a primary tonal peak (P1) and lower frequency secondary peak (P2) are identified. The transition from dipole to quadrupole in the three-dimensional time-averaged vortical structures is also summarized. Notably, suppression of vortex shedding is observed for the cylinder with

A R = 6.5

, while cellular vortex shedding is observed in longer cylinders. The shedding cells near the junction and free tip exhibit lower shedding frequencies compared to the mid-span cell. Wake structures in-phase to the acoustic pressure are examined, confirming both the tip and mid-span related vortex shedding noise of the circular FWMCs. Furthermore, the in-phase structures associated with the primary (P1) peak are characterized by vertical vortex tubes that are well-organized downstream and exhibit strong consistency with Kármán vortex tubes shedding from the mid-span. The coherent structures corresponding to the secondary (P2) peak are found to be concentrated to the free end and are inclined in the downstream direction.

固定在壁上的有限长圆柱体是钝体遇到气流的简化模型，在飞机起落架、汽车附件、风力涡轮机桅杆等领域有着广泛的应用。在本研究中，在雷诺数Re=12,000的条件下，基于圆柱体直径，研究了不同展向纵横比（AR=L/D，其中L为圆柱体长度，D为圆柱体直径）分别为3.2、6.5、12.9和22.6的有限壁挂圆柱体。圆柱体所处壁面的来面层厚度为δ/D=0.83。采用大涡模拟（Large Eddy Simulation， LES）方法模拟紊流，同时求解Ffowcs williams - hawkins方程来预测远场噪声。在宽高比为AR = 3.2、12.9和22.6时，圆形fwmc的声谱特征为一个主音峰（P1）和一个低频次峰（P2）。总结了三维时均涡结构中偶极子向四极子的转变过程。值得注意的是，在AR=6.5的圆柱体中观察到涡脱落的抑制，而在更长的圆柱体中观察到细胞涡脱落。与跨中单元相比，靠近结和自由尖端的脱落单元表现出较低的脱落频率。研究了与声压相一致的尾迹结构，证实了圆形fwmc的尖端和跨中相关的涡脱落噪声。此外，与初级峰（P1）相关的同相结构以垂直涡管为特征，这些垂直涡管在下游组织良好，与Kármán涡管从跨中脱落具有很强的一致性。次级（P2）峰对应的相干结构集中在自由端，并向下游倾斜。

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引用次数: 0

Fully coupled hydroelastic analysis of a membrane-based offshore floating photovoltaic structure: Experimental and numerical studies 基于膜的海上浮动光伏结构的全耦合水弹性分析：实验和数值研究

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-10-08 DOI: 10.1016/j.jfluidstructs.2025.104427

Yifan Zhang , Xiantao Zhang , Hanyu Liu , Dengfeng Fu , Zhenguo Gao

Membrane-based floating photovoltaic (M-FPV) platforms represent an innovative approach to offshore floating photovoltaic systems, characterized by a circular floater and a thin membrane. This research introduces a fully coupled time-domain simulation method to analyze the hydroelastic response of the main structure of these platforms under regular and irregular wave conditions. Modal superposition is employed to assess both in-plane and out-of-plane deformations, while the hydrodynamic forces are obtained using linear potential flow theory, incorporating the modified Morison equation for in-plane loads on the floater. Experimental validation was performed using wave tests in a towing tank. The setup included a horizontal mooring system with four lines. Measurements focused on deformations of both the floater and the membrane, along with mooring forces and wave elevations. The numerical results exhibit good agreement with the experimental data. The wave test results demonstrate the complex interaction between platform flexibility and wave behavior. In regular wave tests, the Response Amplitude Operators (RAOs) reveal that platform flexibility allows the structure to better conform to the wave profile at lower frequencies, while higher frequencies are dominated by structural rigidity, highlighting a significant three-dimensional effect. A distinct difference in in-plane deformation between fore and aft parts under the influence of mooring lines was observed. In irregular wave tests, the vertical motion spectrum of the platform aligns with the wave spectrum, showcasing its flexibility. However, the in-plane longitudinal motion spectrum reveals an additional peak at a frequency approximately twice that of the wave spectrum, attributed to the platform’s surge resonance. This study offers a thorough analysis of M-FPV platforms’ hydroelastic response under regular and irregular waves, informing the design and optimization of offshore PV systems.

膜基浮式光伏（M-FPV）平台代表了海上浮式光伏系统的一种创新方法，其特点是圆形浮子和薄膜。本文采用全耦合时域模拟方法分析了平台主体结构在规则波和不规则波条件下的水弹性响应。模态叠加用于评估面内和面外变形，而水动力则采用线性势流理论，结合修正的Morison方程来计算浮子的面内载荷。通过拖曳槽的波浪试验进行了实验验证。该装置包括一个有四条缆绳的水平系泊系统。测量的重点是浮子和膜的变形，以及系泊力和波浪高度。数值计算结果与实验数据吻合较好。波浪试验结果表明，平台柔性与波浪特性之间存在复杂的相互作用。在常规波浪测试中，响应幅度算子（RAOs）显示，平台的灵活性使结构在较低频率下更好地符合波浪剖面，而较高频率则由结构刚度主导，突出了显著的三维效应。在系泊线的影响下，船首和船尾的面内变形有明显的差异。在不规则波浪测试中，平台的垂直运动谱与波浪谱一致，显示出其灵活性。然而，平面内纵向运动谱显示了一个额外的峰值，其频率大约是波谱的两倍，归因于平台的浪涌共振。本研究深入分析了M-FPV平台在规则波和不规则波作用下的水弹性响应，为海上光伏系统的设计和优化提供了依据。

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引用次数: 0

Dynamics and energies of a wall-clamped flexible membrane in two different cross-flows 夹壁柔性膜在两种不同交叉流中的动力学和能量

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-10-08 DOI: 10.1016/j.jfluidstructs.2025.104436

Zhiwei Liu , Hanfeng Wang , Jiaxuan Li , Ziqiang Zhang , Hui Tang

In order to provide useful guidelines for optimizing piezoelectric energy harvesting designs under near-wall conditions, we experimentally investigate and compare the dynamics and energies of a wall-clamped flexible membrane (FM) in two different cross-flows, i.e., a separated flow induced by a forward-facing step (FFS) and a boundary layer (BL) flow, aiming at revealing the combined effects of the incoming flow and wall contact on flapping dynamics. Four dynamic modes were identified in both the FFS and BL cases by varying flow velocity and FM length: quasi-steady, regular-flapping, tip-contact, and body-contact modes. In the FFS cases, the recirculation zone induced by the step prevents the FM from lodging, whereas in the BL cases, the FM exhibits suppressed amplitudes and near-wall flapping behavior. The evolution of the two contact modes was examined in details, and the variations in contact time and contact distance during the transition between these two modes were quantitatively evaluated. Three-dimensional effects manifest differently in each case, with the FFS showing primarily spanwise bending and the BL case exhibiting pronounced twisting that impacts flapping stability. Energy analysis further reveals that, at high flow velocity, the FM’s kinetic energy dominates over elastic strain energy, with significant energy dissipation occurring during wall contact.

为了对近壁条件下压电能量收集设计的优化提供有用的指导，我们实验研究并比较了壁面夹持柔性膜（FM）在两种不同的交叉流动中的动力学和能量，即由前向台阶（FFS）引起的分离流动和边界层（BL）流动，旨在揭示来流和壁面接触对扑动动力学的综合影响。通过改变气流速度和FM长度，在FFS和BL病例中均识别出四种动态模式：准稳态、规则扑动、尖端接触和身体接触模式。在FFS情况下，台阶诱导的再循环区阻止了调频倒伏，而在BL情况下，调频表现出振幅抑制和近壁扑动行为。详细分析了两种接触模式的演变过程，定量分析了两种模式转换过程中接触时间和接触距离的变化规律。三维效应在每种情况下表现不同，FFS主要表现为展向弯曲，而BL表现为明显的扭曲，影响扑动稳定性。能量分析进一步表明，在高流速下，FM的动能大于弹性应变能，在壁面接触过程中能量耗散明显。

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引用次数: 0

An integrated computational method for vibroacoustic coupling analysis of an underwater structure with a floating raft and acoustic coatings 浮筏-声学涂层水下结构振声耦合分析的综合计算方法

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-10-06 DOI: 10.1016/j.jfluidstructs.2025.104434

Yi-Ni Yang , Hao Wang , Ming-Song Zou , Ye Liu , Guo-Cang Sun , Pei Li

Based on three-dimensional sono-elasticity theory, this study proposes an integrated computational method for vibroacoustic coupling analysis of underwater structures equipped with a floating raft and acoustic coatings in finite water depth. The dynamic substructure method decomposes the complex system into three components: the main structure (including main hull, pedestal, bulkheads, and reinforcing ribs), vibration isolators, and the floating raft. Fluid-structure interaction is exclusively considered in the sono-elasticity coupling between the main structure and water, where the governing equations integrate modal superposition method, simple source boundary integral method, and mirror image virtual source method. The floating raft is modeled using the finite element method, its dynamic response is described by the modal superposition method. The isolators' vibration transmission characteristics are characterized using the four-terminal parameter method. Virtual modes are introduced to achieve dynamic coupling integration at connection boundaries. The impedance matrix model is derived to quantify the vibroacoustic transfer mechanism of acoustic coatings. The proposed methodology demonstrates significant advantages in structural optimization and acoustic performance analysis. Regardless of the modification of any component in the system, the overall response can be recalculated by updating the corresponding stiffness matrix, which substantially improves computational efficiency and engineering adaptability. The accuracy and engineering adaptability of the method are validated by numerical case studies and experimental results, and quantitative analyses are conducted on the influence of submergence depth and acoustic coating layout on acoustic radiation. This work provides theoretical foundations and engineering references for coordinated acoustic-stealth optimization of complex underwater structures.

基于三维声弹性理论，提出了一种有限水深条件下带有浮筏和声学涂层的水下结构振声耦合分析的综合计算方法。动力子结构法将复杂系统分解为三个组成部分：主结构（包括主船体、基座、舱壁和加强肋）、隔振器和浮筏。在主结构与水的声弹性耦合中，只考虑了流固耦合，控制方程集成了模态叠加法、简单源边界积分法和镜像虚源法。采用有限元法对浮筏进行建模，采用模态叠加法对其动力响应进行描述。采用四端参数法对隔振器的振动传递特性进行了表征。引入虚拟模式实现连接边界处的动态耦合集成。推导了阻抗矩阵模型，量化了声学涂层的振动声传递机理。该方法在结构优化和声学性能分析方面具有显著的优势。无论对系统中的任何构件进行修改，都可以通过更新相应的刚度矩阵来重新计算整体响应，大大提高了计算效率和工程适应性。通过数值算例和实验结果验证了该方法的准确性和工程适应性，并定量分析了淹没深度和声涂层布置对声辐射的影响。为复杂水下结构的协同声隐身优化提供了理论基础和工程参考。

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引用次数: 0

A frequency-domain flutter solver for rotary-wing aeroelasticity 旋翼气动弹性颤振频域求解器

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-10-04 DOI: 10.1016/j.jfluidstructs.2025.104435

David Quero

A frequency-domain flutter solver for rotary-wing aeroelasticity is presented. The method applies to linear time-periodic (LTP) aeroelastic systems, including helicopters in forward flight, propellers with yaw angle, and wind energy turbines. It assumes a frequency-domain representation of the aerodynamic model, using the aerodynamic harmonic transfer function (HTF), denoted here as the harmonic generalized aerodynamic force (GAF) matrix. This accounts for the effects of harmonics of the fundamental or forcing frequency. The harmonic GAF exhibits a nonlinear dependence on the Laplace variable, and after coupling with the structural model, the relevant subset of Floquet exponents is determined by solving a nonlinear eigenvalue problem.

This method extends the conventional flutter solvers used in fixed-wing aeroelasticity, which are based on a linear time-invariant (LTI) system. Specifically, it introduces harmonic extensions of the p-k and g flutter solvers, termed the h-p-k and h-g solvers, making them applicable to rotary-wing aeroelasticity. When applied to an LTI system, the method naturally reduces to the standard p-k and g flutter solvers used in fixed-wing aeroelasticity.

The proposed method is demonstrated on a two-degree-of-freedom rotor blade section in forward flight, incorporating an unsteady aerodynamic model based on potential flow theory. It accurately predicts the same advance ratio for flutter onset as the Floquet method while eliminating the need to construct the monodromy matrix. Furthermore, it enables stability analysis even when the aerodynamic model is not available in state-space form, allowing for the use of nonparametric aerodynamic representations.

提出了一种旋翼气动弹性颤振频域求解器。该方法适用于线性时间周期（LTP）气动弹性系统，包括前向飞行的直升机、具有偏航角的螺旋桨和风力涡轮机。它采用气动调和传递函数（HTF）作为气动模型的频域表示，在这里表示为调和广义气动力（GAF）矩阵。这解释了基频或强迫频率的谐波的影响。谐波GAF对拉普拉斯变量具有非线性依赖性，在与结构模型耦合后，通过求解非线性特征值问题确定相关的Floquet指数子集。该方法对传统的基于线性时不变系统的固定翼气动弹性颤振求解方法进行了扩展。具体来说，它引入了p-k和g颤振求解器的谐波扩展，称为h-p-k和h-g求解器，使它们适用于旋翼气动弹性。当应用于LTI系统时，该方法自然地简化为固定翼气动弹性中使用的标准p-k和g颤振求解方法。结合基于势流理论的非定常气动模型，在前飞的二自由度旋翼叶片截面上进行了验证。该方法可以准确地预测与Floquet方法相同的颤振发作提前比，而无需构建单矩阵。此外，即使在状态空间形式的空气动力学模型不可用时，它也可以进行稳定性分析，允许使用非参数空气动力学表示。

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引用次数: 0

Numerical analysis of vortex-induced vibration of deep-sea mining riser with auxiliary pipes based on discrete vortex method 基于离散涡法的深海矿用辅助管立管涡激振动数值分析

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-10-03 DOI: 10.1016/j.jfluidstructs.2025.104431

Guangrui Zhang, Yanbin Wang, Deli Gao

Air injection and discharge pipes play an essential role in the deep-sea mining airlift process, and their influence on the flow field and riser vortex-induced vibration (VIV) is not fully investigated. In this study, the discrete vortex method is modified to incorporate the influence of multiple solid domains, and the flow field evolution in the presence of auxiliary pipes is simulated. Based on the assumption that the vortex structure is constant within a certain spanwise length, an analytical model is established by strip theory and a weakly coupled fluid-structure interaction approach to investigate riser VIV in the cross-flow direction. The results show that the auxiliary pipes will interfere with the vortex shedding of the main riser and inhibit the formation of a stable wake pattern, which leads to a reduction in both the amplitude and frequency of the lift force. The VIV exhibits a mixed behavior of standing and travelling waves, and multi-mode responses induced by temporal drift of the frequency can be observed. In addition, the auxiliary pipes suppress the VIV by disturbing vortex shedding and increasing the bending stiffness of the riser. Moreover, the effects of inflow angle, current velocity, and vessel navigational motion on the VIV response and power region distribution are investigated. Specifically, a 45° inflow angle provides optimal VIV suppression and leads to the narrowest power-in region, while vessel motion in either the upstream or downstream direction aggravates VIV and significantly alters the power region distribution.

注排气管在深海采矿气举过程中起着至关重要的作用，但其对流场和隔水管涡激振动的影响尚未得到充分的研究。本文对离散涡旋法进行了改进，纳入了多个固体域的影响，并模拟了辅助管道存在时的流场演化。基于涡结构在一定展长范围内不变的假设，采用条形理论和弱耦合流固耦合方法建立了横流方向上立管涡动的解析模型。结果表明，辅助管道会干扰主隔水管的涡流脱落，抑制稳定尾迹的形成，导致升力的幅值和频率降低。该系统表现出驻波和行波的混合特性，并且可以观察到频率随时间漂移引起的多模态响应。此外，辅助管通过干扰旋涡脱落和增加立管的弯曲刚度来抑制涡激振动。此外，还研究了入流角、流速和船舶航行运动对涡激振动响应和功率区域分布的影响。具体来说，45°入流角提供了最佳的涡激振动抑制，并导致最窄的动力区域，而船舶在上游或下游方向的运动加剧了涡激振动，并显著改变了动力区域的分布。

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引用次数: 0

Higher resonances improve the swimming performance of flexible bio-inspired propulsors 更高的共振提高了柔性仿生推进器的游泳性能

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-10-03 DOI: 10.1016/j.jfluidstructs.2025.104433

Patrick F. Musgrave , Charles M. Tenney

This study establishes the role of higher resonant frequencies on the swimming performance of flexible bio-inspired propulsors. Biological and bio-inspired swimmers typically swim at or near their first resonance to achieve high efficiency and thrust. These swimmers also have higher resonances that could yield the same performance benefits; however, the role of these higher resonances is not well understood. This study experimentally identifies the thrust, kinematics, and power performance of flexible propulsors across resonances and uncovers the fluid-structural mechanism that governs the performance. We experimentally test multiple propulsors that share a simplified design consisting of a constant cross-section beam excited by piezoelectric actuators in quiescent water and with stiffnesses in the range of biological swimmers. Our results demonstrate that higher resonances significantly improve the performance compared to the fundamental resonance yielding a

2 \times

increase in thrust to power ratio, up to

11 \times

increase in absolute thrust, while requiring

< 25 %

of the displacement amplitude.

While the higher resonances yield better overall performance, we show that higher resonances are less effective at converting tail velocity into thrust since the thrust coefficient depends on the mode shape. We determine that higher resonances engage less fluid mass, and show that the effective aspect ratio (wavelength normalized by width) is a predictor of performance across resonances. These results indicate that higher resonances could be a viable swimming option to improve the thrust and efficiency of stiffer bodied swimmers while yielding smaller displacement amplitudes that improve operation near obstacles.

本研究建立了高共振频率对柔性仿生推进器游泳性能的影响。生物和仿生游泳者通常在他们的第一共振处或附近游泳，以达到高效率和推力。这些游泳者也有更高的共振，可以产生同样的性能优势；然而，这些高共振的作用还没有得到很好的理解。本研究通过实验确定了柔性推进器跨共振的推力、运动学和动力性能，并揭示了控制性能的流固机制。我们实验测试了多个推进器，它们共享一个简化的设计，包括在静水中由压电致动器激发的恒定截面光束，其刚度在生物游泳者的范围内。我们的研究结果表明，与基本共振相比，更高的共振显著提高了性能，使推力功率比增加了2倍，绝对推力增加了11倍，而位移幅度需要<；25%。虽然较高的共振产生更好的整体性能，但由于推力系数取决于模态振型，因此较高的共振在将尾速度转换为推力时效果较差。我们确定较高的共振占用较少的流体质量，并表明有效纵横比（波长按宽度归一化）是跨共振性能的预测因子。这些结果表明，更高的共振可能是一种可行的游泳选择，可以提高身体较硬的游泳者的推力和效率，同时产生更小的位移振幅，从而改善在障碍物附近的操作。

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引用次数: 0

Experimental investigation of torsional effects on cross-flow oscillations in flow-induced vibrations of a triangular prism 三角棱镜流激振动中扭转效应对横流振荡的实验研究

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-10-01 DOI: 10.1016/j.jfluidstructs.2025.104428

Seyedmohammad Mousavisani, Farnaz Feyli, Banafsheh Seyed-Aghazadeh

This study experimentally investigates the flow-induced vibration (FIV) response of a rigid equilateral triangular prism with one and two degrees of freedom (DoF). The primary focus is on assessing how introducing rotational oscillations (a second DoF) influences cross-flow (CF) oscillations (the first DoF) through a series of water tunnel experiments. The system’s dynamic response is characterized at five initial angles of attack (

α = 0 °, 15 °, 30 °, 45 °, 60 °

), within a Reynolds number range of 525 to 3,817. For the one-DoF configuration in the CF direction, a galloping-type instability is observed at

α = 45 °

and

60 °

. However, when torsional motion is introduced as a second DoF, the onset of oscillations is delayed, and the amplitude of CF oscillations is significantly reduced. This suppression is attributed to changes in the mean angle of attack and the influence of periodic rotational oscillations. The periodic prism rotation modifies the flow-afterbody interaction, leading to weakened flow forces in the CF direction and further reducing the vibration amplitude. Particle Image Velocimetry (PIV) measurements reveal notable differences in the wake structures between the one- and two-DoF cases. In the two-DoF configuration, the prism’s rotation shifts the separation points, leading to asymmetric vortex shedding between the upper and lower sides. This asymmetry periodically modulates the wake dynamics and sustains the rotational oscillations of the prism.

实验研究了一自由度和二自由度刚性等边三角棱镜的流激振动响应。主要重点是通过一系列水洞实验来评估引入旋转振荡（第二自由度）对横流振荡（第一自由度）的影响。系统的动态响应在5个初始攻角（α=0°，15°，30°，45°，60°）下，雷诺数范围为525至3817。对于CF方向的单自由度构型，在α=45°和60°处观察到驰动型不稳定性。然而，当扭转运动作为第二自由度引入时，振荡的开始被延迟，并且CF振荡的幅度显着降低。这种抑制归因于平均攻角的变化和周期性旋转振荡的影响。周期性的棱镜旋转改变了流-后体相互作用，导致CF方向的流动力减弱，进一步降低了振动幅值。粒子图像测速（PIV）测量揭示了尾迹结构在单自由度和双自由度情况下的显著差异。在双自由度结构中，棱镜的旋转使分离点移位，导致上下两侧不对称的旋涡脱落。这种不对称性周期性地调节了尾流动力学，并维持了棱镜的旋转振荡。

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引用次数: 0

Three-dimensional fluid–structure interaction diagnostics using a single camera 利用单摄像机进行三维流固相互作用诊断

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-10-01 DOI: 10.1016/j.jfluidstructs.2025.104423

Bibek Sapkota, Holger Mettelsiefen, Vrishank Raghav, Brian S. Thurow

A new method for fluid–structure interaction (FSI) diagnostics to simultaneously capture time-resolved three-dimensional, three-component (3D3C) velocity fields and structural deformations using a single light field camera is presented. A light field camera encodes both spatial and angular information of light rays collected by a conventional imaging lens that allows for the 3D reconstruction of a scene from a single image. Building upon this capability, a light field fluid–structure interaction (LF FSI) methodology is developed with a focus on experimental scenarios with low optical access. Proper orthogonal decomposition (POD) is used to separate particle and surface information contained in the same image. A correlation-based depth estimation technique is introduced to reconstruct instantaneous surface positions from the disparity between angular perspectives and conventional particle image velocimetry (PIV) is used for flow field reconstruction. Validation of the methodology is achieved using synthetic images of simultaneously moving flat plates and a vortex ring with a small increase in uncertainty under

\sim

0.5 microlenses observed in both flow and structure measurement compared to independent measurements. The method is experimentally verified using a flat plate translating along the camera’s optical axis in a flow field with varying particle concentrations. Finally, simultaneous reconstructions of the flow field and surface shape around a flexible membrane are presented, with the surface reconstruction further validated using simultaneously captured stereo images. The findings indicate that the LF FSI methodology provides a new capability to simultaneously measure large-scale flow characteristics and structural deformations using a single camera.

提出了一种利用单光场相机同时捕捉时间分辨三维三分量（3D3C）速度场和结构变形的流固耦合诊断方法。光场相机对传统成像镜头收集的光线的空间和角度信息进行编码，从而允许从单个图像中对场景进行3D重建。在此能力的基础上，开发了一种光场流固相互作用（LF FSI）方法，重点关注低光通道的实验场景。采用适当的正交分解（POD）对同一图像中包含的粒子和表面信息进行分离。引入了一种基于相关深度估计的流场重建技术，利用角度视差重建瞬时表面位置，而传统的粒子图像测速法（PIV）用于流场重建。该方法的验证是使用同时移动的平板和涡流环的合成图像来实现的，与独立测量相比，在流量和结构测量中观察到的~ 0.5微透镜下的不确定性略有增加。通过实验验证了该方法在不同颗粒浓度流场中沿相机光轴平移的平板。最后，同时重建了柔性膜周围的流场和表面形状，并使用同时捕获的立体图像进一步验证了表面重建。研究结果表明，LF FSI方法提供了一种使用单个相机同时测量大规模流动特性和结构变形的新能力。

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引用次数: 0

Analytical solutions for the flexural–gravity and capillary–gravity wave resistances due to a steadily moving concentrated load 稳定移动集中荷载下挠曲重力波和毛细重力波阻力的解析解

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-09-30 DOI: 10.1016/j.jfluidstructs.2025.104430

D.Q. Lu

The interfacial flexural–gravity waves due to a concentrated load steadily moving on the thin elastic plate floating on the interface between two immiscible fluids of different densities are investigated analytically. The two inviscid fluids are assumed to be incompressible and homogeneous, and the motion be irrotational. The equation of motion for the plate, including the elastic force, the compressive force and the inertial force, is imbedded in the dynamic boundary conditions on the interface. Based on the linear potential theory for small-amplitude waves, the integral solutions for the interfacial wave profiles and wave resistances are derived by the Fourier transform. The dispersion relation and the exact solutions for the wave numbers are explicitly deduced. It is found the wave dynamical behaviors depend on the relation between the moving speed and the minimal phase speed. The maximal allowable value for the compressive force is obtained, at which the minimal phase speed is zero and the wave motion can be stimulated with any nonzero moving speed of the load due to the presence of compressive stress in the plate. The effects of the flexural rigidity and the fluid density ratio are also explored. The solutions for the capillary–gravity wave can readily be recovered by discarding the elastic force in the present formulation.

本文分析研究了在两种不同密度的非混相流体界面上漂浮的弹性薄板上，集中载荷稳定运动所引起的界面弯曲重力波。假定这两种无粘流体是不可压缩和均匀的，运动是无旋的。将弹性力、压缩力和惯性力的运动方程嵌入到界面的动态边界条件中。基于小振幅波的线性势理论，用傅里叶变换导出了界面波剖面和波阻的积分解。明确地推导了色散关系和波数的精确解。研究发现，运动速度与最小相速之间的关系决定了波的动力特性。得到了压应力的最大允许值，在该值下，最小相速为零，由于板内存在压应力，载荷的任何非零移动速度都可以激发波的运动。探讨了抗弯刚度和流密度比的影响。通过抛弃本公式中的弹性力，可以很容易地恢复毛细管重力波的解。

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引用次数: 0