Measurement of structural intensity in submerged plates and shells using nearfield acoustical holography Free

Nearfield acoustical holography provides a complete mapping of the normal surface velocity distribution on the surface of a plate or cylindrical shell. For plates this measurement completely determines the full structural intensity (SI) in the plate and no assumptions need to be made about the wave field on the plate. In shells this normal velocity is not sufficient to determine the SI accurately (below the ring resonance) because of the coupling between in‐plane velocity and out‐of‐plane velocity. Several techniques are presented to predict the in‐plane velocities from a knowledge of the normal (radial) velocity taken from measured holographic data and the corresponding SI is calculated and compared. In addition, the instantaneous energy exchange between the shell and the nearfield in the fluid (the coupling between structural and acoustic intensity) is obtained from measured data and presented.