Numerical analysis on fishlike swimming with immersed boundary method

Abstract

The immersed boundary method is an effective way to handle complex geometries and moving geometries within a flow field. In this paper, two-dimensional numerical simulations of fishlike swimming are conducted based on the immersed boundary method. In the process of calculation, the velocity and pressure coupling is solved using a second-order pressure correction method and the Lagrangian force density is calculated using Physical Virtual Model. In order to verify validity and feasibility of the algorithm, flow around a circular cylinder and moving cylinder in stationary flow are simulated, and then the results are compared with other researches. After that, the modeling and simulation of fish-like swimming are conducted. At each time step, the shape and position of the fish is updated and the Lagrangian force density is calculated. The shape and position of the fish are calculated based on the motion equation and the forces acting on the boundary. Furthermore, the impacts on performance of motion frequency, wavelength and amplitude are studied.