Near field determination of the complex radiation efficiency and acoustic intensity distribution for a resonantly vibrating surface

An experimental procedure is described which allows both the resistive and reactive parts of the acoustic radiation efficiency of a resonantly vibrating surface to be determined from measurements in the acoustic near field. In addition, the procedure allows the precise quantitative location on the vibrating surfaces of acoustic sources which radiate energy to the far field. The method described here allows far greater detailed investigation of an acoustically radiating surface than is possible with alternative experimental procedures described in the literature.C.H. Hansen and D.A. Bie