This work consists of evaluating the performances of a new membrance separation process: an annular, swirling, decaying flow induced by a tangential inlet. For this purpose, we have compared the permeation flux obtained in swirling flow with that of a crossflow. We ultrafiltered a model suspension of bentonite in order to compare the performances of the two modules for different operating conditions. Parameters such as flow rate, Reynolds number and wall velocity gradient were studied, and this last one appears to be a significant hydrodynamic parameter to compare the performances of the two configurations. Indeed, this parameter takes into account the flow field nature and, more precisely, the shear stress at the membrane surface. improvement of the permeation flux induced by the swirling, decaying flow in comparison with that observed in cross-flow can reach more than 30% under specific conditions. The study of the energy consumption of these two cells allows us to confirm the interest of the swirling, decaying flow in order to design new types of membrane separation modules.