1. A SIREN DEVICE COMPRISING A CASING AND A ROTOR HAVING AN AXIAL INLET CHAMBER AND AN OUTER SURFACE PARALLEL TO THE INNER SURFACE OF SAID CASING, CENTRIFUGAL FLOW PASSAGEWAYS IN SAID ROTOR EXTENDING IN STRAIGHT LINES THERETHROUGH FROM SAID AXIAL INLET CHAMBER TO A CYLINDRICAL SURFACE PORTION OF THE ROTOR PERIPHERY, AT LEAST ONE ELONGATED DISCHARGE NOZZLE PROJECTING THROUGH SAID CASING FROM AN INLET OPENING IN SAID CYLINDRICAL SURFACE PORTION SUBSTANTIALLY TANGENTIALLY THERETO SAID CYLINDRICAL SURFACE PORTION BEING COAXIAL WITH A CORRESPONDINGG CYLINDRICAL SURFACE PORTION OF THE INNER SURFACE OF THE CASING AND THE ENDS OF SAID PASSAGEWAYS BEING DIRECTLY ADJACENT TO SAID CYLINDRICAL INNER SURFACE PORTION, WHEREBY THE CENTRIFUGAL FLOW FROM SAID PASSAGEWAYS, WHEN SAID ROTOR IS ROTATING, WILL DIRECTLY DISCHARGE BY IMPULSES THROUGH SAID INLET OPENING.