Oscillatory or pulsatile flows are produced on a hydrodynamic bench by a volumetric gear pump. The moto-pump group is an original device which is very different from other systems. It is driven by a wave synthesizing generator which enables any flow rate to be produced especially oscillatory, pulsatile or physiological flow. The synthesizing generator delivers a periodic wave with variable amplitude, shape and frequency. The moto-pump group is controlled by an amplifying comparator; it produces a flow whose rate follows the control signal. A study of the modifications of flow patterns induced by models of vascular stenoses has been performed with this bench. The study of the velocity distribution has been effected with a pulsed Doppler ultrasonic velocimeter.