MOVEMENT OF A FILM OF DISSIPATIVE FLUID I N AN ENCLOSED AREA UNDER THE INFLUENCE OF AN EXTENDED SOURCES

In recent years, the growing demand for miniaturized transducers and t he widespread use of silicon technology, has focused interest on the d esign of condenser or electret microphones on a silicon chip. But the theoretical models used are those existing for conventional microphone s, which do not remain valid for miniaturized transducers, if good acc uracy is expected. The main purpose of the paper is to consider the fo rced vibrations of the membranes (or plates), driven by an external so urce (here an incident acoustic pressure field), backed by a very thin layer of fluid and a rigid plane wall, and surrounded by a reservoir around its periphery. The ''exact'' statement of the problem is obtain ed by taking into account effects of heat conduction, bulk and shear v iscosity, impedance of the surrounding cavity, and so on, avoiding the approximations currently in use. An improved analytical solution is o btained and some new features are indicated.