A critical assessment of the immersed boundary method for modeling flow around fixed and moving bodies

This paper reports the verification and validation of the immersed boundary methods implemented in the open-source toolbox FOAM-Extend version 4.0 and 4.1. Five test cases with increasing complexity are studied and the simulation results are compared with the experimental and numerical data found in the literature. A solver is developed based on the Immersed Boundary Surface Method (IBS) which is an advanced cut-cell finite volume immersed boundary technique. By integrating the Lagrangian equations of motion with the IBS, this solver is capable of simulating fluid-particle interactions. The benchmark studies indicated that the IBS yields excellent results for stationary immersed bodies. Even though the flow field is captured satisfactorily for moving bodies, spurious force oscillations are present in these cases. Simulating different size particles in a channel flow shows that the spurious force oscillations can negatively affect the prediction of particle dynamic motion, although the severity depends on the value of the particle Stokes number.