Numerical study of propulsion performance in swimming fish using boundary element method

Abstract

In this paper, hydrodynamic simulation of fish-like swimming for two types of aquatic animals including tuna fish and giant danio is presented. We employ an unsteady three-dimensional inviscid boundary element method including time stepping algorithm to capture the wake sheet and flow features around swimming fish in a straight course. At each time step, an unsteady Bernoulli equation was used to find the pressure distribution and thrust generated by the animal. To couple fluid solver with kinematic equations of flexible body, undulating motions of backbone were defined using a prescribed continuous function. Although the flexible motion mechanism controls the fish swimming but no structural model has been considered for the body, there is no fluid–solid interaction. To validate the model, we compare our results with the numerical work of Zhu et al. [1] and experimental results of Barrett et al. [2] and show that this methodology could be fast and reliable approach for the prediction of flexible propulsors.