In order to improve the endurance mileage and the sailing speed of micro underwater vehicles, it is critical to reduce the drag of underwater devices. However, the existing underwater drag reducers are not suitable for micro underwater device due to its large size and complex structure. Inspired by the adaptive deformation of fish to achieve traveling wave drag reduction when the flow field changes, a micro piezo-actuated traveling wave drag reducer (PTWDR, the size of 30 mm × 28 mm × 0.75 mm), which can be embedded into the wall of the micro vehicle and hardly increasing the volume and weight of the vehicle, is proposed in this work to realize active drag reduction. The mechanism of active disturbing the turbulent boundary layer by piezoelectric micro-amplitude traveling waves to achieve drag reduction has been revealed. The drag reduction performance control method, which can meet different drag reduction requirements, is given. The experimental results of frictional drag and total drag indicate that the designed micro PTWDR is feasible to reduce the drag. The maximum local drag reduction rate of 47 % can be achieved at resonance frequency, which can improve the maneuverability of micro vehicles. While when the low frequency is applied, it cannot only obtain a certain drag reduction rate in a large drag reduction area, but also realize net energy saving. This work provides a novel and effective theoretical and technical reference for realizing active drag reduction and net energy saving, which can be applied for micro underwater vehicles.

中文翻译：

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利用微压电致动器实现行波减阻

为了提高微型水下航行器的续航里程和航行速度，降低水下装置的阻力至关重要。然而，现有的水下减阻器由于其尺寸较大、结构复杂，不适合微型水下装置。受流场变化时鱼体自适应变形实现行波减阻的启发，设计了一种微压电驱动行波减阻器（PTWDR，尺寸为30 mm×28 mm×0.75 mm），可嵌入到鱼体中。本工作提出了微型车辆壁的设计，并且几乎不增加车辆的体积和重量，以实现主动减阻。揭示了压电微幅行波主动扰动湍流边界层实现减阻的机理。给出了满足不同减阻要求的减阻性能控制方法。摩擦阻力和总阻力的实验结果表明，所设计的微型PTWDR降低阻力是可行的。在共振频率下可实现最大47%的局部减阻率，可提高微型车辆的机动性。而采用低频时，不仅能在大减阻面积内获得一定的减阻率，还能实现净节能。该工作为实现主动减阻和净节能提供了新颖有效的理论和技术参考，可应用于微型水下航行器。