Purpose

This paper aims to carry out the research on the influence of ground effect on the performance of robotic fish propelled by oscillating paired pectoral fins.

Design/methodology/approach

The two-dimensional ground effect model of the oscillating pectoral fin without considering flexible deformation is established by introducing a two-dimensional fluid ground effect model. The parameters of the influence of ground effect on the oscillating pectoral fin are analyzed. Finally, the ground effect test platform is built, and a series of hydrodynamic experiments are carried out to study the influence of ground effect on the propulsion performance of the robotic fish propelled by oscillating paired pectoral fins under different motion parameters.

Findings

The thickness of the trailing edge and effective clearance are two important parameters that can change the influence of ground effect on the rigid pectoral fin. The experimental results are consistent with that obtained through theoretical analysis within a certain extent, which indicates that the developed two-dimensional ground effect model in this paper can be used to analyze the influence of ground effect on the propulsion performance of the oscillating pectoral fin. The experiment results show that the average thrust increases with the decreasing distance between the robot fish and the bottom. Meanwhile, with the increase of oscillation frequency and amplitude, the average thrust increases gradually.

Originality/value

The developed two-dimensional ground effect model provides the theoretical basis for the further research on the influence of ground effect on the propulsion performance of the oscillating pectoral fin. It can also be used in the design of the bionic pectoral fins.

中文翻译：

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地面效应对成对的胸鳍振荡推动的机器鱼性能的影响研究

目的

本文旨在研究地面效应对由一对成对的胸鳍振荡引起的机器人鱼性能的影响。

设计/方法/方法

通过引入二维流体地面效应模型，建立了不考虑柔性变形的胸鳍摆动的二维地面效应模型。分析了地面效应对摆动的胸鳍的影响的参数。最后，建立了地面效应测试平台，并进行了一系列水动力实验，研究了地面效应对在不同运动参数下振动成对的胸鳍推动的机器人鱼推进性能的影响。

发现

后缘的厚度和有效间隙是可以改变地面效应对刚性胸鳍的影响的两个重要参数。实验结果在一定程度上与理论分析相吻合，表明本文建立的二维地面效应模型可用于分析地面效应对胸鳍振荡性能的影响。实验结果表明，平均推力随着机器人鱼与水底距离的减小而增大。同时，随着振荡频率和振幅的增加，平均推力逐渐增加。

创意/价值

所建立的二维地面效应模型为进一步研究地面效应对摆动式胸鳍推进性能的影响提供了理论依据。它也可以用于仿生胸鳍的设计。