Effect of actuation method on hydrodynamics of elastic plates oscillating at resonance
Effect of actuation method on hydrodynamics of elastic plates oscillating at resonance
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DOI：
10.1017/jfm.2020.915
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发表时间：
2021-01
影响因子：
3.7
通讯作者：
E. Demirer;Yu-cheng Wang;A. Erturk;A. Alexeev
中科院分区：
文献类型：
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作者：
E. Demirer;Yu-cheng Wang;A. Erturk;A. Alexeev
摘要本文研究了两种不同的激励方法对弹性矩形板共振振动的影响。板由根部的插入运动驱动，或由雷诺数在500和4000之间的分布内弯矩驱动。后一种驱动方法代表内部驱动的智能材料，并模仿游泳动物的自然能力，不断改变其形状与肌肉。我们进行实验与暴跌的弹性板和压电板致动器，使用完全耦合的三维计算模型的基础上的格子玻尔兹曼方法模拟。经过实验验证的计算模型，探测板流体动力学的参数范围很广，包括大的振荡幅度，提示非线性效应。两种驱动方法之间的比较表明，对于相同水平的尖端偏转，外部驱动板显着优于内部驱动板的推力产生和流体动力学效率。内部驱动板的性能降低与其次优弯曲形状有关，这导致后缘几何形状具有增强的涡量产生和粘性耗散。此外，驱动方法的差异影响表征板振荡的惯性系数，特别是对于大振幅。研究发现，惯性系数强烈依赖于尖端偏转振幅和雷诺数，和驱动方法，特别是对于较大的振幅。
Abstract In this work we investigate the effects of two distinct actuation methods on the hydrodynamics of elastic rectangular plates oscillating at resonance. Plates are driven by plunging motion at the root or actuated by a distributed internal bending moment at Reynolds numbers between 500 and 4000. The latter actuation method represents internally actuated smart materials and emulates the natural ability of swimming animals to continuously change their shapes with muscles. We conduct experiments with plunging elastic plates and piezoelectric plate actuators that are simulated using a fully coupled three-dimensional computational model based on the lattice Boltzmann method. After experimental validation the computational model is employed to probe plate hydrodynamics for a wide range of parameters, including large oscillation amplitudes which prompts nonlinear effects. The comparison between the two actuation methods reveals that, for the same level of tip deflection, externally actuated plates significantly outperform internally actuated plates in terms of thrust production and hydrodynamic efficiency. The reduced performance of internally actuated plates is associated with their suboptimal bending shapes which leads to a trailing edge geometry with enhanced vorticity generation and viscous dissipation. Furthermore, the difference in actuation methods impacts the inertia coefficient characterizing the plate oscillations, especially for large amplitudes. It is found that the inertia coefficient strongly depends on the tip deflection amplitude and the Reynolds number, and actuation method, especially for larger amplitudes.