Study on the hydrodynamic performance of a self-propelled robot fish swimming in pipelines environment

Pipeline inspection technologies have become frontier topics. This paper proposes a method for pipeline inspection by using a self-propelled robot fish. To investigate the hydrodynamic performance of robot fish in pipelines environment, a series of numerical simulation and experimental test are performed. A continuous pipeline model which contains 4 types of different pipeline segments is established to study the hydrodynamic coefficients and flow field distribution of robot fish at different oscillating frequencies f and pipelines.The selfpropelled speed test experiments are conducted to further reveal the propulsion performance of robot fish in different pipelines. The results indicate that the self-propelled speed, hydrodynamic coefficients, propulsive efficiency, and swimming stability of the robot fish change with the size and shape of the pipelines. The effect of pipelines on the propulsive performance of robot fish occurs when the diameter of the pipeline decreases to a certain value. Square pipeline with the same feature size as circular pipeline has the smaller effect on the propulsive performance of robot fish. Moreover, changing the oscillating frequency f can obtain different hydrodynamic performance.