Fluid-structure interaction of a flapping flexible plate in quiescent fluid

Abstract

This paper presents the computational analysis of a fluid-structure interaction for a flapping flexible plate in quiescent fluid to investigate the effect of flexibility on the generation of propulsion that is critical for birds, insects, and micro-air vehicles with flapping wings. It is known that rotation of the flapping rigid plate or wing near the end of a translational stroke enhances propulsion. This study found that flexibility improves the efficiency of propulsion during the rotation process and creates an optimal point in the propulsion. The lattice Boltzmann method with an immersed boundary technique using a direct forcing scheme is used to simulate the fluid, while the finite element method with Euler beam elements is used to model structural deformation of the flexible plate. The direct forcing scheme of the lattice Boltzmann method was improved by introducing a participation ratio, which represents the ratio of fluid lattice points to effective interpolated points and modifies the force term for the zero-thickness plate.