On buoyancy‐driven viscous incompressible flows with various types of boundary conditions

In this paper, we study the existence and uniqueness of solutions to the initial‐boundary‐value problem for time‐dependent flows of heat‐conducting incompressible fluids through the two‐dimensional channel. The boundary conditions are of two types: the so‐called “do nothing” boundary condition on the outflow and the so‐called Navier boundary conditions on the solid walls of the channel. A priori estimates play a crucial role in existential analysis, however, the considered mixed boundary conditions do not enable us to derive an energy‐type estimate of the solution. Our aim is to prove the existence and uniqueness of a solution on a sufficiently short time interval for arbitrarily large data.