UCLA

A new fluid-structure interaction approach for bio-inspired regime is presented. In this method, the incompressible fluid flow is discretized using the fast immersed boundary method with nullspace approach, previously developed by Colonius and Taira. The Lagrangian solid dynamics solver is greatly inspired from the virtual node algorithm by Zhu et al. The two system are coupled to satisfy the physical constraints at their interface.

A new weak formulation of the immersed boundary method coherently enforces the interface force balance and the no-slip condition. Boundary stresses are treated as Lagrange multipliers to maintain a strong coupling. Strongly coupled solver are known to handle problems on which weakly coupled methods encounter stability restrictions (problems including large density ratio for instance).

Numerical simulations have been conducted to model the vibrations of an initially perturbed elastic disk immersed in a fluid. Results have shown an inconsistency in the enforcement of the boundary stress term on the fluid system. Accuracy and convergence of the solid and the fluid solvers have been evaluated.