Przepływ laminarny w kanale o zmiennym przekroju z ruchomymi i porowatymi ściankami

The problem is considered as a slightly disturbed Poisseuille flow, so the Navier-Stokes equations can be linearized with respect to small perturbations. The solution is obtained in an analytical form, containing an unknown pressure function which can be found from the ordinary linear differential equation derived here. The equation has been solved for some simple axisymmetric flows, each of them being influenced by only one of the three disturbance effects mentioned in the head of this paper. In this way pressure and velocity disturbance for the main flow and its perturbations has been obtained. Some remarks on the limitations of the method presented have also been included.