On robustness to a topological perturbation in fluid mechanics

The robustness to topological perturbations in geometrical domains filled by a fluid flowing in Stokes–Darcy regime is considered. The cost functional is given by the energy dissipation in the fluid. The topological perturbation is carried out by the nucleation of an infinitesimal circular obstacle, which can be considered as a small measurement device. Our approach is based on the topological derivative method, which has been previously employed in the shape and topology optimization problems. The topological derivative (TD) measures the sensitivity of a given shape functional with respect to topological domain perturbations. The TD is used to determine the location of the small device placement, through a distributed control problem. By taking into account the effect of the disturbance term or uncertain input data in the TD expression, the problem of robustness to topological perturbation for the energy functional can be formulated as a minimax optimization problem with a pointwise observation. Numerical examples illustrate the efficiency of the proposed topological derivative method.