Existence and regularity for perturbed Stokes system with critical drift in 2D

Abstract: We consider a perturbed Stokes system with critical divergence-free drift in a bounded Lipschitz domain in $R^2$, with sufficiently small Lipschitz constant L. It extends our previous work in $\Bbb R^n, n\ge 3$, to two-dimensional case. For large drift in weak $L^2$ space, we prove unique existence of q-weak solutions for force in $L^q$ with q close to 2. Moreover, for drift in $L^2(\Bbb R^2)$ we prove the unique existence of $W^{1,2}$ solutions for arbitrarily large L. Using similar methods we can also prove analogous results for scalar equations with divergence-free drifts in weak $L^2$ space.