Numerical Simulation of the Interaction Between Fluid Flow and Elastic Flaps Oscillations

Several numerical methods have been developed recently to solve problems including the interaction between viscous fluid flow and elastic solid structures. In this work, an in-house partitioned numerical solver is developed by using the open source C++ library OpenFOAM. Finite volume method is used to discretize the fluid flow problem on a moving mesh in an Arbitrary Lagrangian-Eulerian formulation and by using an adaptive time step. The structural elastic deformation is analyzed in a Lagrangian formulation using the St. Venant-Kirchhoff constitutive law. The solid structure is discretized by the finite volume method in an iterative segregated approach. The automatic mesh motion solver is based on Laplace smoothing equation with variable mesh diffusion. The strong coupling between the segregated solvers and the equilibrium on the fluid-structure interface are achieved by using an iterative implicit fixed-point algorithm with dynamic Aitken’s relaxation method. The solver is first validated on a benchmark largely used in the open literature. Then, a more complex case is studied including two elastic flaps immersed in a pulsatile fluid flow. The present solver predicts accurately the interaction between the complex flow structures generated by the flaps and the effect of the flaps oscillations on each other.