Simulation of Backward Facing Step Flow using Immersed Boundary Method by FVM

Abstract

The ability to handle complex geometries with fluid-solid interactions has been one of the most challenging issues in the field of Computational Fluid Dynamics (CFD) as most of the engineering problems that exist nowadays are dealing with complex geometries. There are two methods that have been studied and developed for now which are the immersed boundary method (IBM) and the body fitted mesh method (BFM). This paper studies about the simulations on backward facing step flow using immersed boundary method by finite volume method. The two different approaches which are the IBM represented by structured grid and BFM represented by unstructured grid were being studied throughout the research. Although 2D backward facing step is considered as one of the simplest flows, it is still widely studied by a lot of researchers as it is a benchmark problem in the engineering field and the physics involved in the flow is complicated. Comparisons of the two methods which are the IBM and BFM are made in terms of the differences in total pressure, velocity profiles and acoustics power level of different Reynold number. The grid and mesh are generated by ANSYS Workbench. IBM is considered as a better method in handling complex geometries than the BFM and it is easier to construct a uniform grid generation. The parameters of the Re are 100, 500, 1000, 2500, 5000 and 10000. From the obtained results, it showed that the most active region of this flow is at the downstream near the step. The total pressure, velocity magnitude and acoustics power level are fluctuating in that region as it is the recirculation region.