Note on the effect of grad-div stabilization on calculating drag and lift coefficients

In recent years, grad-div stabilization has become a popular technique for improving the mass conservation of a solution to the incompressible Navier-Stokes equations (NSE). Grad-div stabilization can be easily implemented in any code that already uses the very common Taylor-Hood finite elements. In this paper we do a close review of the grad-div stabilized and modular grad-div stabilized NSE applied to a well-known benchmark problem: 2D flow around a cylindrical obstacle. We show that using current methods grad-div stabilization can change the calculated drag and lift coefficients. We will then suggest a remedy for the given test problem and verify our results by showing the grad-div parameters agree with the reference values and those calculated using Scott-Vogelius finite elements.