Near-field identification of vibration sources, resonant cavities, and diffraction using acoustic intensity measurements

Abstract

Near-field acoustic intensity measurements are a powerful analysis and diagnostic tool when all available measured quantities are utilized. The advantage of considering the reactive intensity and complex specific acoustic impedance along with the active intensity is stressed. An added feature to the data presentation is the pressure phase that is reconstructed from the time-independent measured data. The active intensity plots are thus enhanced by superimposing the lines of constant phase so that the wave-front propagation is visualized. In the first measurement configuration, an active source absorbing power is differentiated from a resonant cavity absorbing power and diffraction is localized. In the second configuration, the mode shape of a vibrating plate is identified.