Decoupled stabilized finite element methods for the Boussinesq equations with temperature-dependent coefficients

In this paper, the decoupled stabilized finite element methods are developed for the Boussinesq equations with temperature dependent coefficients. In our numerical schemes, the original problem is decoupled into the linearized Navier-Stokes equations and a parabolic problem, the low order mixed finite element pairs are used to approximate the spatial spaces and the backward Euler scheme is adopted to treat the time terms. Furthermore, the linear terms are dealt with the implicit scheme while the nonlinear terms are treated by the semi-implicit scheme, then, a lot of storage and computational cost are saved. The advantages for our numerical schemes are parameter-free, unconditionally stable, and constant matrix at each time level. Finally, some numerical tests are presented to verify the theoretical results of the developed numerical methods, and show that our schemes not only keep good accuracy but also save a lot of computational times.