Abstract: A process for causing to vibrate at determined frequencies pieces having a relatively large surface, notably plane pieces, wherein a volume comprising the piece or pieces to be caused to vibrate is achieved, said piece or pieces are elastically connected to the walls of said volume wherein a fluid is running so that it supports the surface or surfaces to be caused to vibrate and vibrations are periodically generated in said fluid so as to generate shock-waves in succession which, in turn, cause the vibration at a frequency corresponding to that of the piece or pieces elastically mounted.