Journal of Fluids and Structures最新文献_第5页

Transient flow analysis in pipes with extended deteriorations considering fluid-structure interaction: The role of support stiffness 考虑流固耦合的扩展劣化管道瞬态流动分析：支撑刚度的作用

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-11-17 DOI: 10.1016/j.jfluidstructs.2025.104466

Roohollah Zanganeh , Alireza Keramat , Arris Tijsseling

In prior research, the potential for misdiagnosis between the effects of Fluid-Structure Interaction (FSI) and pipe-wall Extended Deteriorations (EDs) has been highlighted for transient flow in a pipeline. Given the significant role of pipeline anchor stiffness in modulating FSI during waterhammer (WH), this study delves into the combined impacts of FSI and EDs on WH signals in a pipeline with elastic supports. A time-domain numerical solution, using the finite-element method (FEM) for the structure and the method of characteristics (MOC) for the fluid, is employed to scrutinise the transient pressure-head fluctuations owing to FSI and EDs. The results demonstrate that the stress wave reflections from EDs generate pressure head jumps during WH. Furthermore, the interaction of the stress wave in the pipe wall with the pressure wave reflected from EDs in a deteriorated pipeline affects the transient signature. FSI and the stiffness of pipe supports alter the timing, shape, and magnitude of pressure-head jumps caused by EDs. The support’s stiffness is varied to quantify its impact. The study underscores the importance of the excitation signal’s bandwidth (the valve closure time) in determining the prominence of FSI and ED signatures within transient signals. This research contributes to the fundament of the transient-based defect detection (TBDD) technique applied in pipelines.

在之前的研究中，流固耦合效应（FSI）和管壁延伸劣化（EDs）之间的潜在误诊已经在管道瞬态流动中得到了强调。考虑到管道锚固刚度在水击过程中对水击信号的调制作用，本研究探讨了弹性支撑管道中水击信号中水击强度和水击强度的联合影响。利用结构有限元法（FEM）和流体特性法（MOC）的时域数值解，仔细研究了由于FSI和EDs引起的瞬态压头波动。结果表明，在高压下，EDs的应力波反射会产生压头跳变。此外，管道内壁的应力波与老化管道中EDs反射的压力波的相互作用影响了瞬态特征。FSI和管道支架的刚度会改变由EDs引起的压头跳变的时间、形状和幅度。支持的刚度是可变的，以量化其影响。该研究强调了激励信号的带宽（阀门关闭时间）在确定瞬态信号中FSI和ED特征的显著性方面的重要性。该研究为瞬态缺陷检测技术在管道中的应用奠定了基础。

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引用次数: 0

A strongly coupled 3D BEM-FEM fluid–structure interaction model for the analysis of flexible biomimetic thrusters 柔性仿生推进器的强耦合三维BEM-FEM流固耦合模型

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-11-15 DOI: 10.1016/j.jfluidstructs.2025.104464

Dimitra Anevlavi, Kostas Belibassakis

Biomimetic propulsors that emulate the kinematics of famous thunniform swimmers, such as the Bluefin tuna and the humpback whale, offer an eco-friendly alternative to conventional propellers for autonomous underwater vehicles. Their advantages include low-frequency operation, advanced maneuverability, and high efficiency during long-distance cruising. Related research suggests that elasticity, advanced control, and properly tuned material parameters are key for emulating nature in thruster applications. The present work proposes a strongly coupled fluid–structure interaction model that addresses the hydroelastic response prediction problem, supporting the design of flexible flapping-foil thrusters. The developed 3D FSI model consists of an unsteady boundary element method for the lifting-surface problem and a finite element method, based on Discrete Kirchhoff Triangles for thin plates with stiffness variation, for the structural problem. The response of elastic wings is implicitly non-linear since deformations affect the hydrodynamic load excitation and vice-versa. Therefore, strong coupling is crucial for accurately capturing the underlying physics. Comparisons against experimental data support the validity of the developed FSI numerical scheme, suggesting that it can facilitate the design of concept thrusters with enhanced performance using optimization and elastic parameter tuning.

仿生推进器模仿著名的鳍状游泳者的运动学，如蓝鳍金枪鱼和座头鲸，为自主水下航行器提供了传统螺旋桨的环保替代品。其优点是运行频率低、机动性强、长距离巡航效率高。相关研究表明，弹性、先进的控制和适当调整的材料参数是在推进器应用中模拟自然的关键。本文提出了一个解决水弹性响应预测问题的强耦合流固耦合模型，为柔性扑翼型推进器的设计提供了支持。所建立的三维FSI模型包括求解升力面问题的非定常边界元法和求解结构问题的基于离散Kirchhoff三角形的有限元法。弹性翼的响应是隐式非线性的，因为变形会影响水动力载荷的激励，反之亦然。因此，强耦合对于准确捕获底层物理是至关重要的。通过与实验数据的比较，验证了所提出的FSI数值方案的有效性，表明该方案可以通过优化和弹性参数调整来促进概念推进器性能的提高。

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引用次数: 0

Experimental analysis of collapsible tube dynamics in pulsatile flow conditions 脉动流动条件下可折叠管动力学实验分析

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-11-11 DOI: 10.1016/j.jfluidstructs.2025.104468

Sifat Karim Chowdhury, Yan Zhang

This experimental study explores the influence of pulsatile flow on collapsible tube dynamics and the corresponding fluid–structure interactions, which are fundamental to understanding various biological flow phenomena. A hyperelastic tube model was tested in a closed-loop flow system under controlled transmural pressure variations. High-speed imaging and Particle Image Velocimetry (PIV) were employed to quantify tube wall deformation and fluid flow dynamics across varying Reynolds (Re) and Womersley (Wo) numbers. Results indicate that at highly positive transmural pressures, tubes remain distended with minimal oscillations, while at near-neutral conditions, cyclic buckling and propagation of wall deformation occur in axial direction. Under highly negative transmural pressures, self-excited oscillations emerge potentially caused by the instability under supercritical conditions. Flow limitation was observed as transmural pressure decreased, with mean Reynolds number having a stronger influence than pulsatile frequency. This research provides valuable insights into the complex dynamics in collapsible tubes under pulsatile flow, with potential applications in understanding various physiological systems such as the respiratory tract and circulatory system. The results offer benchmark data for validating computational fluid–structure interaction models and contribute to the broader field of biofluid mechanics.

本实验探讨脉动流动对可折叠管动力学的影响以及相应的流固相互作用，这是理解各种生物流动现象的基础。在控制跨壁压力变化的闭环流动系统中对超弹性管模型进行了试验。采用高速成像和粒子成像测速技术（PIV）对不同雷诺数（Re）和沃默斯利数（Wo）下的管壁变形和流体流动动力学进行量化。结果表明，在高正跨壁压力下，管道保持膨胀，振荡最小，而在近中性条件下，循环屈曲和壁面变形的传播发生在轴向。在高负跨壁压力下，超临界条件下的不稳定性可能引起自激振荡。随着跨壁压力的降低，流动受限，平均雷诺数比脉动频率的影响更大。该研究为脉动流作用下可折叠管的复杂动力学提供了有价值的见解，在理解呼吸道和循环系统等各种生理系统方面具有潜在的应用价值。这些结果为验证计算流固耦合模型提供了基准数据，并为生物流体力学的更广泛领域做出了贡献。

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引用次数: 0

Deflection of a floating ice sheet under a moving load: Influence of uniform current and elastic bottom 移动荷载作用下漂浮冰盖的挠度：均匀电流和弹性底的影响

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-11-11 DOI: 10.1016/j.jfluidstructs.2025.104465

Mahesh Kumar Nehra, Swaroop Nandan Bora

This study examines the wave response of a thin floating ice sheet due to a moving load subject to a uniform current and a flexible sea-bottom of finite depth. It takes into account the effects of both bottom elasticity and the uniform current on the ice sheet deflection by considering the flexible bottom as a thin elastic plate. The relevant dispersion relation is derived through mathematical analysis. Assuming the fluid to be incompressible, and inviscid, and the motion irrotational, the problem is formulated by following the linear water wave theory. Phase and group speeds of waves depending on various physical scenarios are explored using the dispersion relation. A particular type of loading function is taken into consideration, which depicts a line load that moves on the ice surface at a constant speed. The Fourier transform method is used to find out the deflection caused by the moving load and to examine the effects of the elastic sea-bed and uniform current. To make the procedure simple, the resultant integrals are transformed into a non-dimensional form. Furthermore, the ice sheet response for large time is examined using an asymptotic method. The phase speed, group speed, and ice deflection are further illustrated by graphical depictions to analyze the effects of the important aspects. The variation of the parameters of the elastic sea-bed and the current results in considerable alternation of the wave propagation due to the moving load on the ice sheet. The study indicates that both the uniform current and the elasticity of sea-bed have considerable effects on wave propagation and ice sheet deformation, presenting important insights into wave-ice-elastic bed interactions in geophysical habitats.

本研究考察了受均匀水流和有限深度柔性海底的移动载荷作用下薄浮冰的波浪响应。将柔性底板视为弹性薄板，同时考虑了底部弹性和均匀电流对冰盖挠度的影响。通过数学分析，导出了相关色散关系。假设流体不可压缩，无粘性，无旋转运动，该问题是按照线性水波理论来表述的。利用色散关系探讨了不同物理情形下波的相速和群速。考虑到一种特殊类型的加载函数，它描述了在冰面上以恒定速度移动的线载荷。利用傅里叶变换方法找出了移动荷载引起的挠度，并考察了弹性海床和均匀电流的影响。为了使过程简单，所得到的积分被转换成无量纲形式。此外，用渐近方法研究了大时间冰盖的响应。进一步用图形说明了相速度、群速度和冰的偏转，分析了这些重要方面的影响。弹性海床和海流参数的变化，在冰盖上的移动荷载作用下，波浪的传播发生了很大的变化。研究表明，均匀洋流和海床弹性对波的传播和冰盖的变形都有相当大的影响，为地球物理栖息地中波-冰-弹性床的相互作用提供了重要的见解。

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引用次数: 0

Impact loads and ice plate damage during the process of icebreaking and water exit for the vehicle 车辆破冰出水过程中的冲击载荷和冰板损伤

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-11-09 DOI: 10.1016/j.jfluidstructs.2025.104463

Zhiqiang Fu , Zhipeng Li , Longquan Sun , Guihui Ma , Siqiang Wang

Underwater vehicles in polar environments invariably encounter complex operating conditions, including interactions with ice and water. The substantial impact loads and hydrodynamic forces generated by the interaction among the vehicle structure, ice, and water during the processes of icebreaking and crossing the water can significantly affect the safety of the vehicle. Therefore, the processes of ice plate breakup, fluid flow characteristics, and the associated complex load dynamics during the icebreaking operations warrant thorough investigation. In response to this need, this paper presents a set of experimental systems designed to study vehicle icebreaking and water-exit. A type of breakable frozen model ice is used in the experiment, and research is conducted on icebreaking loads and the breakup of ice plates when vehicles impact ice plates of varying thicknesses and sizes at different speeds. The results of experiments indicate that radial cracks develop first, followed by the propagation of circumferential cracks. The study reveals that, due to the obstruction posed by the ice plate, an instantaneous pressure peak occurs at the vehicle's bow as it contacts the ice. This pressure is released once the ice sheet breaks, resulting in a splash. Furthermore, as the ice plate length increases, fluctuations in the pressure peak at the vehicle bow are noted. Concurrently, the axial force exhibits an overall upward trend as the size of the ice sheet increases. The findings of this study can serve as a valuable reference for the comprehensive design of marine structures intended for polar operations.

水下航行器在极地环境中总是遇到复杂的操作条件，包括与冰和水的相互作用。在破冰和渡水过程中，车辆结构与冰、水相互作用产生的巨大冲击载荷和水动力会对车辆的安全性产生重大影响。因此，在破冰作业中，冰板破碎过程、流体流动特性以及相关的复杂载荷动力学需要深入研究。针对这一需求，本文设计了一套研究车辆破冰出水的实验系统。实验采用一种可破冰冰冻模型冰，研究车辆以不同速度撞击不同厚度和尺寸的冰板时的破冰载荷和冰板破碎情况。试验结果表明，径向裂纹首先形成，其次是周向裂纹的扩展。研究表明，由于冰板的阻碍，当车辆接触冰时，车辆的船头会出现瞬时压力峰值。一旦冰盖破裂，这种压力就会释放，导致水花飞溅。此外，随着冰板长度的增加，可以注意到车辆艏压力峰值的波动。同时，轴向力随冰盖尺寸的增大总体呈上升趋势。本研究结果可为极地作业海洋结构的综合设计提供有价值的参考。

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引用次数: 0

Aeroelastic response of an airfoil with structural freeplay in transonic buffeting flow 跨声速抖振流中具有结构自由的翼型气动弹性响应

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-11-08 DOI: 10.1016/j.jfluidstructs.2025.104445

Michael Candon , Vincenzo Muscarello , Wim Verhagen , Pier Marzocca , Oleg Levinski

Transonic shock buffet is a nonlinear, unsteady aerodynamic phenomenon characterized by self-sustained, periodic shock oscillations that can critically affect aircraft structural integrity. While the aerodynamic aspects of shock buffet have been widely studied, its interaction with nonlinear structural dynamics remains largely unexplored. This paper presents, for the first time, a numerical investigation of aeroelastic interactions arising from the coupling of shock buffet with a nonlinear structural model featuring pitch freeplay. Using Unsteady Reynolds-Averaged Navier–Stokes (URANS) simulations coupled with a two-degree-of-freedom heave–pitch airfoil model, the study reveals that structural nonlinearity can induce aerodynamic lock-in to superharmonics of the heave natural frequency, resulting in 2:1 and 3:1 lock-in mechanisms and large-amplitude heave limit cycles. These newly identified lock-in behaviors expand the current understanding of transonic aeroelastic instabilities. The influence of key parameters such as structural-to-fluid mass ratio and structural damping on these phenomena is also systematically examined. This work introduces a novel class of aeroelastic lock-in mechanism with significant implications for transonic flight dynamics and aircraft design.

跨声速冲击是一种非线性、非定常的气动现象，其特征是自我持续的周期性冲击振荡，可以严重影响飞机结构的完整性。虽然冲击冲击的气动方面已经得到了广泛的研究，但它与非线性结构动力学的相互作用在很大程度上仍然是未知的。本文首次用数值方法研究了振动冲击与具有俯距自由运动的非线性结构模型之间的气动弹性相互作用。利用非定常雷诺数-平均纳维-斯托克斯（URANS）模拟和二自由度重-俯仰翼型模型，研究表明，结构非线性会导致升沉固有频率超谐波的气动锁定，导致2:1和3:1的锁定机制和大振幅的升沉极限环。这些新发现的锁定行为扩展了目前对跨音速气动弹性不稳定性的理解。系统地研究了结构与流体质量比和结构阻尼等关键参数对这些现象的影响。这项工作介绍了一类新的气动弹性锁定机构，对跨音速飞行动力学和飞机设计具有重要意义。

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引用次数: 0

Experimental investigation of flexible trailing edge effects on airfoil turbulent-boundary-layer noise 柔性尾缘对翼型湍流边界层噪声影响的实验研究

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-11-08 DOI: 10.1016/j.jfluidstructs.2025.104467

Qian Liu , Reza Maryami , Lin Li , Yu Liu

The acoustic characteristics of the NACA 0012 airfoil with a flexible trailing edge (TE) are experimentally investigated. Measurements are conducted at chord-based Reynolds numbers ranging from

1.93 \times 1 0^{5}

and

1.16 \times 1 0^{6}

, with the airfoil set at a zero angle of attack. Flexible TEs made of polyethylene terephthalate, polypropylene, and polyvinyl chloride strips are employed to assess their impact on noise reduction. To elucidate the effect of TE deformation on acoustic performance, the out-of-plane deformation is recorded using high-speed cameras and analyzed with a digital image correlation algorithm. The acoustic results demonstrate that flexible TEs reduce noise by 1–3 dB within the mid-frequency range, with its upper limit shifting to higher frequencies as the free-stream velocity increases, following a scaling law of

f \sim U^{1.5}

. However, noticeable tonal noise persists across various free-stream velocities, with its frequency remaining relatively consistent. Deformation analysis shows that the vibration of the flexible strip plays a key role in generating vortex shedding, which in turn leads to tonal noise. This is further supported by proper orthogonal decomposition (POD) analysis, which indicates that bending deformation, especially near the tip of the strip, is the primary mechanism driving vortex shedding. This bending deformation, associated with lower-order POD modes, generates large-scale flow structures that propagate acoustic waves to the far field, thereby contributing to the observed tonal noise.

对NACA 0012柔性后缘翼型的声学特性进行了实验研究。测量是在弦为基础的雷诺数范围从1.93×105和1.16×106进行，与翼型设置在零迎角。采用聚对苯二甲酸乙二醇酯、聚丙烯和聚氯乙烯条制成的柔性TEs来评估它们对降低噪音的影响。为了阐明TE变形对声学性能的影响，利用高速摄像机记录了TE变形的面外变形，并用数字图像相关算法进行了分析。声学结果表明，柔性TEs在中频范围内降低了1-3 dB的噪声，随着自由流速度的增加，其上限向更高的频率移动，遵循f ~ U1.5的比例定律。然而，在不同的自由流速度下，明显的音调噪声仍然存在，其频率保持相对一致。变形分析表明，柔性带材的振动是产生涡旋脱落的主要原因，而涡旋脱落又导致了调性噪声的产生。适当的正交分解（POD）分析进一步支持了这一点，表明弯曲变形，特别是在带钢尖端附近的弯曲变形，是驱动旋涡脱落的主要机制。这种弯曲变形与低阶POD模式相关联，产生大规模的流动结构，将声波传播到远场，从而导致观察到的音调噪声。

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引用次数: 0

Experimental study on ice breaking by flexural-gravity waves induced by a moving submerged spheroid 水下运动球体诱导弯曲重力波破冰的实验研究

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-11-08 DOI: 10.1016/j.jfluidstructs.2025.104451

Hao Tan , Linhua Sun , Baoyu Ni , Shan Wang , Hua-Dong Yao , C. Guedes Soares

A prolate spheroid model is towed beneath an ice sheet in outdoor ice-tank experiments to study the effects of a moving pressure source, which can induce flexural-gravity waves in an ice sheet. To replace the previous cable-driven system, a new underwater towing setup is developed, constraining both the spheroid's horizontal and vertical motions. For the first time, the hydrodynamic forces acting on the body beneath the ice sheet can be directly measured using this setup. Results demonstrate that the spheroid velocity, submergence depth, and ice thickness jointly govern the maximum ice deflection, damage severity, and the drag and lift characteristics of the spheroid. The drag and lift coefficients vary non-monotonically with the velocity, exhibiting distinct differences from the spheroid moving beneath a free surface or a rigid wall. A new dimensionless parameter is proposed to improve the existing ice failure criteria. This new criterion is based on measured ice deflection and a characteristic length scale of the ice sheet, providing a practical and robust parameter for wave-induced ice failure.

在室外冰槽实验中，研究了移动压力源对冰盖弯曲重力波的影响。为了取代以前的缆索驱动系统，开发了一种新的水下拖曳装置，既限制了球体的水平运动，也限制了球体的垂直运动。这是第一次，用这种装置可以直接测量作用在冰盖下身体上的水动力。结果表明，球体速度、淹没深度和冰厚共同决定了球体的最大冰挠度、损伤程度以及阻力和升力特性。阻力和升力系数随速度非单调变化，与在自由表面或刚性壁面下运动的球体表现出明显的不同。提出了一种新的无量纲参数来改进现有的冰破坏准则。该准则基于实测冰的挠度和冰盖的特征长度尺度，为波浪引起的冰破坏提供了一个实用且可靠的参数。

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引用次数: 0

Evaluation of calculation methods for time-averaged hydrodynamic forces on tandem flapping flexible plates: Velocity–pressure integration versus vorticity-based formulations 串联扑动柔性板上时间平均水动力计算方法的评价：速度-压力积分与基于涡度的公式

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-11-06 DOI: 10.1016/j.jfluidstructs.2025.104450

Dehan Yuan , LinLin Kang , Weicheng Cui , Dixia Fan

This study examines the relationship between the complex wake of tandem flexible plates and the time-averaged force, while comparing the strengths and limitations of two time-averaged force theories. Expressions for the time-averaged force are derived at both the velocity–pressure and vortical levels and analyzed in comparison. The findings indicate no direct correlation between the wake velocity profile and the time-averaged force. Accurate force predictions require both velocity and pressure information from the wake. The vortical-level theory, which omits pressure information, offers practical advantages in experimental fluid mechanics by linking fluid structures to time-averaged forces. In contrast, the velocity–pressure perturbation theory enables force predictions using near-field velocity data. A systematic comparison of the two theories is provided, with recommendations for the decomposition of the physical mechanisms of time-averaged forces in flow field diagnostics and the selection of appropriate control volumes.

本文探讨了柔性板复合尾迹与时均力之间的关系，并比较了两种时均力理论的优缺点。推导了速度-压力和垂直水平下的时间平均力表达式，并进行了比较分析。研究结果表明，尾迹速度剖面与时间平均力之间没有直接关系。准确的力预测需要来自尾流的速度和压力信息。涡流水平理论忽略了压力信息，通过将流体结构与时间平均力联系起来，为实验流体力学提供了实用的优势。相比之下，速度-压力摄动理论可以使用近场速度数据来预测力。对这两种理论进行了系统的比较，并对流场诊断中时间平均力的物理机制分解和适当控制体积的选择提出了建议。

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引用次数: 0

Energy harvesting from vortex-induced vibrations using a pendulum 利用钟摆从涡激振动中收集能量

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Journal of Fluids and Structures

Pub Date : 2025-11-06 DOI: 10.1016/j.jfluidstructs.2025.104449

F.J. Huera-Huarte

This paper presents an experimental investigation into energy harvesting from vortex-induced vibrations (VIV) using a pendulum-based arrangement. A series of experiments were conducted in a water channel to examine the effects of flow velocity and applied braking torque on the pendulum shaft. The motion of the pendulum and the fluid loading were measured and analyzed to assess the power output and dynamic response of the system under varying flow and braking conditions. Results indicate that energy extraction is maximized within a narrow range of flow velocities that induce lock-in response, particularly for the highest braking torques that allow motion on the system. A constant (limited) braking torque was applied to evaluate mechanical power at the shaft, and while the braking function was not optimized, the study demonstrates that the system can achieve energy conversion efficiencies comparable to other VIV-based energy harvesting configurations.

本文介绍了一种利用摆结构收集涡激振动能量的实验研究。在水道中进行了一系列试验，考察了流速和制动扭矩对摆轴的影响。通过测量和分析摆的运动和流体载荷，评估系统在不同流量和制动条件下的功率输出和动态响应。结果表明，在引起锁定响应的狭窄流速范围内，能量提取是最大的，特别是对于允许系统运动的最高制动扭矩。采用恒定（有限）制动扭矩来评估轴处的机械功率，虽然制动功能没有优化，但研究表明，该系统可以实现与其他基于viv的能量收集配置相当的能量转换效率。

引用次数: 0