SMOOTHING EFFECT AND WELL-POSEDNESS FOR 2D BOUSSINESQ EQUATIONS IN CRITICAL SOBOLEV SPACE

In this paper, we investigate the fractional dissipation 2D Boussinesq equations with initial data in the critical space u(0) is an element of H2-2 alpha(R-2) and theta(0) is an element of H2-2 beta(R-2). The local well-posedness for the equations is firstly established by using some a priori estimates for the solution in L-p(0, T; H2-p-1/p2 alpha(R-2)) x L-p(0, T; H2-p-1/p2 beta (R-2)) with some suitable p. And then the generalized blow-up criterion and smoothing effect are obtained in turn, which improves some of the previous results for (critical, subcritcial or supcritical) Boussnesq equations. The results of the present paper are based on the Littlewood-Paley theory and the nonlinear lower bounds estimates for the fractional Laplacian, and can be treated as a generalization of results for 2D quasi-geostrophic equation.