Optimal condition of boundary flex control for the systems governed by Boussinesq equation with the press boundary condition and mixed boundary condition

In this paper, the boundary flex control problem of non stationary equation governing the coupled mass and heat flow of a viscous incompressible fluid in a generalized Boussinesq approximation by assuming that viscosity and heat conductivity are dependent on temperature has been studied. The boundary condition for velocity of fluid is non -standard boundary condition: specifically the case where dynamical pressure is given on some part of the boundary and the boundary condition for temperature of fluid is mixed boundary condition has been considered. The optimal condition has been derived. Then, Pontryagin's maximum principle in the special case has been derived.