Simulation of self-coordination in a row of beating flexible flaplets for micro-swimmer applications: Model and experiment study

In this study, we present a model that simulates hydrodynamic self-coordination in a row of flexible flaplets. We control the flaplets in order that their tips follow a fixed-amplitude oscillatory motion profile. When brought together at a low Reynolds-number environment, the flaplets interact with each other in the form of bending deflections at their tips, which causes the frequency of the individual oscillations to vary until a coordinated steady state is reached. The model design steps are experimentally verified and the coordination results of both the experiment and the model are compared. The model's internal states are then analysed for a better understanding of the synchronization collective effect. The coordination of the flaplets is found to settle in the direction of propulsion forces ascent. The stability of the resulted synchronization and propulsion forces are examined over long periods. The model is meant to be simplified and mostly linear so that it can be utilized for state forecasting in a real-time control application of a swimmer robot. Finally, we experimentally study the propulsion performance of five beating flaplets that follow prescribed oscillation profiles forming a metachronal wave. The flow results show that the flaplets, that beat in coordination, are efficient at generating a uni-directional steady-streaming transport of the fluid at their surface. (c) 2020 Elsevier Ltd. All rights reserved.