Comparison of spheroidal and eigenfunction-expansion trial functions for a membrane in an infinite baffle.
The on-axis far-field pressure response of a circular membrane in an infinite baffle when driven by a uniformly distributed electrostatic force is calculated using two different trial functions for the surface velocity distribution. The first is an expansion based upon a solution to the free space wave equation in oblate spheroidal coordinates, which has already been derived in a previous paper [J. Acoust. Soc. Am. 120(5), 2460-2477 (2006)], and the second is a membrane eigenfunction expansion (or Bessel series), which is rigorously derived in this letter. Although the latter can be used as a basis for calculating a number of different radiation characteristics such as the radiation impedance or directivity, etc., only the on-axis far-field sound pressure is considered here. The results are compared and discussed.
Nokia UK Ltd., Nokia House, Summit Avenue, Farnborough, Hants GU14 0NG, United Kingdom. tim.mellow@nokia.com
Tim
T
Mellow
Leo
L
Kärkkäinen
D000162:Acoustics; D004548:Elasticity; D007700:Kinetics; D008433:Mathematics; D008567:Membranes, Artificial; D008962:Models, Theoretical; D012542:Scattering, Radiation; D014465:Ultrasonics; D014783:Viscosity
D008567:Membranes, Artificial