Patent ID: 8218318

Claim:
A cooling device using pulsating fluid for cooling of an object, the device comprising: a transducer having a membrane adapted to generate pressure waves at a working frequency (f w ), and a cavity enclosing a first side of said membrane, said cavity enclosing the first side of said membrane having at least one opening adapted to emit a pulsating net output fluid flow towards said object, the at least one opening of cavity enclosing the first side of said membrane connected to the cavity via a channel, said channel having a length (L p ) less than λ/20, where λ is the wavelength in the fluid corresponding to f=f w , wherein the at least one opening of the cavity enclosing the first side of said membrane is in gaseous fluid communication with a second side of said membrane, and wherein said cavity is sufficiently small to prevent fluid in said cavity from acting as a spring in a resonating mass-spring system in the working range, such that a volume velocity (u 1 ) at the at least one opening of the cavity enclosing the first side of said membrane is substantially equal to a volume velocity (u 1 ′) at the second side of the membrane.