## 3pSP8. Theoretical model to describe the coupling between a vibrating membrane and thin gas layers.

### Session: Wednesday Afternoon, December 4

### Time: 4:05

**Author: Pierrick Lotton**

**Location: Lab. d'Acoust., assoc. au C.N.R.S., Inst. d'Acoust. et de Mecan., Univ. du Maine, Av. O. Messiaen, B. P. 535, 72017 Le Mans Cedex, France**

**Author: Michel Bruneau**

**Location: Lab. d'Acoust., assoc. au C.N.R.S., Inst. d'Acoust. et de Mecan., Univ. du Maine, Av. O. Messiaen, B. P. 535, 72017 Le Mans Cedex, France**

**Abstract:**

A theoretical model to describe the behavior of a membrane loaded by gas
films has recently been developed. This analytical model is required by the
current level of miniaturization of acoustical transducers and by new devices
and applications, especially in the high-frequency range (up to 100 kHz and
more). It is based on the fundamental acoustical and mechanical equations (the
Navier--Stokes equation, the conservation of mass equation, the Fourier equation
for heat conduction, the equation of motion of the membrane) and includes
realistic boundary conditions. These equations are simplified by making
assumptions based on the fact that the thicknesses of fluid films are very
small. Then, conventional models, based on equivalent electrical networks,
generally used to describe the behavior of electrostatic or piezoelectric
microphones or loudspeakers, are improved. For example, the influence of the
viscosity, the heat conduction, and the deformation of the membrane in the
high-frequency range can be accurately taken into account.

ASA 132nd meeting - Hawaii, December 1996