  This paper aims to compare and evaluate various obstacle approximation
techniques employed in the context of the steady incompressible Navier-Stokes
equations. Specifically, we investigate the effectiveness of a standard volume
penalization approximation and an approximation method utilizing high viscosity
inside the obstacle region, as well as their composition. Analytical results
concerning the convergence rate of these approaches are provided, and extensive
numerical experiments are conducted to validate their performance.
