An IB-LBM for FSI Problems Involving Viscoelastic Fluids and Complex Geometries

Abstract

An immersed boundary-lattice Boltzmann method (IB-LBM) for fluid-structure interaction (FSI) problems involving viscoelastic fluids and complex geometries with a few validation cases is presented in this paper. In this method, the lattice Boltzmann method is used to solve the fluid dynamics and the constitutive equations of viscoelastic fluids. An artificial damping is introduced to enhance numerical stability in solving the constitutive equations. A hybrid of the finite difference method (2D and 3D rigid particles) and the finite element method (3D capsule) is employed to solve the structural dynamics. The interaction between the solid structure and the fluid is achieved by an immersed boundary method. The present method and models are validated by several cases including 2D Oldroyd-B channel flow, 2D lid-driven cavity flow, 2D Oldroyd-B flow over a confined cylinder, a 2D rigid particle migration in an Oldryod-B Couette flow, a spherical particle rotation in an Oldroyd-B shear flow, a spherical particle settling in a Newtonian fluid, and the deformation of a spherical capsule in a long channel filled with a Newtonian fluid.