An Explicitly Decoupled Variational Multiscale Method for Incompressible, Non-Isothermal Flows

We propose, analyze and test a fully decoupled, but still unconditionally stable and optimally accurate, variational multiscale stabilization (VMS) for incompressible, non-isothermal fluid flows. The VMS stabilization is implemented as a post-processing step, and thus can be used with existing codes. A full numerical analysis of the method is given that proves unconditional stability with respect to the timestep size, and that the method converges optimally in both time and space. Numerical tests are provided that confirm the theoretical results, and test the method on a benchmark problem for Marsigli flow.