  A volume penalization-based immersed boundary technique is developed and
thoroughly validated for fluid flow problems, specifically flow over bluff
bodies. The proposed algorithm has been implemented in an Open Source Field
Operation and Manipulation (OpenFOAM). For capturing the fluid-solid interface
more accurately, the grid is refined near the solid surface using topoSetDict
and refineMeshDict utilities in OpenFOAM. In order to avoid any numerical
oscillation, the present volume penalization method (VPM) is integrated with a
signed distance function, which is also referred to as a level-set function.
Benchmark problems, such as flows around a cylinder and a sphere, are
considered and thoroughly validated with the results available in the
literature. For the flow over a stationary cylinder, the Reynolds number is
varied so that it covers from a steady 2D (two-dimensional) flow to an unsteady
3D (three-dimensional) flow. The capability of the present solver has been
further verified by considering the flow past a vibrating cylinder in the
cross-stream direction. In addition, a flow over a sphere, which is inherently
three-dimensional due to its geometrical shape, is validated in both steady and
unsteady regimes. The results obtained by the present VPM show good agreement
with those obtained by a body-fitted grid using the same numerical scheme as
that of the VPM, and also with those reported in the literature. The present
results indicate that the VPM-based immersed boundary technique can be widely
applicable to scientific and engineering problems involving flow past
stationary and moving bluff bodies of arbitrary geometry.
