Optimal control for quasi-Newtonian flows with defective boundary conditions

We consider a generalized-Newtonian fluid with defective boundary conditions where only flow rates or mean pressures are prescribed on parts of boundary. The defect boundary condition problem is formulated as an optimal control problem in which a Neumann or Dirichlet boundary control is used for matching given flow rates or mean pressures. For the constrained optimization problem an optimality system is derived from which a solution of the problem is obtained. Computational algorithms are discussed and numerical results are also presented.