Current Research | Biomimetics

Multi-body Dynamics Modelling on a Self-propelled Pufferfish with Rigid Fins

By Ruoxin Li, Dr Qing Xiao

In the present research, a self-propelled pufferfish with three rigid fins, i.e. caudal, dorsal and anal fins, is modelled with our in-house multi-body dynamics code. The model is extracted from a live fish experiment, which was tested at Shanghai Jiao Tong University (SJTU), China. The motion of the fish fins is also obtained from the experiment and the locomotion of the fish body is fully induced by the oscillating motion of fish fins and entirely determined by computation. Hydrodynamic forces are integrated using a Computational Fluid Dynamics method in the commercial software package Fluent.

The following animation shows the self-propelled fish motion in still water as well as the vorticity contour coloured by pressure. In this case, the phase angles of dorsal and anal fins are identical while there is a phase angle difference of pi for the caudal fin.