The paper aims to illustrate the algorithm developed in the paper [6] in some specific problems of shape optimization issued from fluid mechanics. Using the fictitious domain method with penalization, the fluid equations will be solved in a fixed domain. The admissible shapes are parametrized by continuous function defined in the fixed domain, then the shape optimization problem becomes an optimal control problem, where the control is the parametrization of the shape. We get the directional derivative of the cost function by solving co-state equation. Numerical results are obtained using a gradient type algorithm.