Hydrodynamics of a fish using fluid structure interaction

Abstract

Systems which involve flexible bodies interacting with surrounding fluid flow are commonplace. For example flapping flags and swimming fishes are becoming increasingly prevalent in bio-fluid engineering applications. These phenomena are challenging to model numerically on account of complex geometries and freely moving boundaries, which give rise to complicated fluid dynamics. In these systems, the flexible body acts on the surrounding fluid, forcing it to move with the moving boundary. On the other manner, the fluid exerts forces on the flexible body through pressure differences and viscous shear stresses. Collectively, the interactions between the fluid and the flexible-body can give rise to self-sustained oscillations such as the flapping of a flag. The fluid-flexible structure interaction is also an essential aspect of the tail and wing motions of swimming and flying animals. Fish is one of the oldest aquatic beings known to man. It has not only fascinated him but also has been a source of inspiration. A large number of scientists and engineers are working on developing a underwater vehicle with the efficiency of that of a fish. The current work aims at understanding the hydrodynamics involved in swimming of a fish using fluid structure interaction. The magnitude and frequencies of disturbances formed due to Von Karmen Vortex past the fish are calculated thus providing an insight into the drag effects due to these deformation on the fish.