Fluid-structure interaction of multi-body systems: Methodology and applications

TL;DR

This paper introduces a cost-effective, weakly coupled computational method for fluid-structure interaction in multi-body systems, validated through literature comparisons and demonstrated with bio-inspired three-dimensional applications.

Contribution

The paper develops a novel weakly coupled approach combining fractional-step and immersed boundary methods for multi-body fluid-structure interactions.

Findings

Method accurately simulates flexible airfoil and flag dynamics

Validated against literature for 2D and 3D cases

Successfully applied to bio-inspired 3D systems

Abstract

We present a method for computing fluid-structure interaction problems for multi-body systems. The fluid flow equations are solved using a fractional-step method with the immersed boundary method proposed by Uhlmann [J. Comput Phys. 209 (2005) 448]. The equations of the rigid bodies are solved using recursive algorithms proposed by Felis [Auton. Robot 41 (2017) 495]. The two systems of equations are weakly coupled so that the resulting method is cost-effective. The accuracy of the method is demonstrated by comparison with two- and three-dimensional cases from the literature: the flapping of a flexible airfoil, the self-propulsion of a plunging flexible plate, and the flapping of a flag in a free stream. As an illustration of the capabilities of the proposed method, two three-dimensional bio-inspired applications are presented: an extension to three dimensions of the plunging flexible plate and a simple model of spider ballooning.