Supersonic Acoustic Intensity for Sound Power Prediction

The noise of some consumer products comes from their structural vibrations. The sound power can be predicted in early product design phases through finite element, boundary element, and statistical energy analysis methods. This is done by propagating the simulated surface pressure and velocity outwards and integrating the intensity over an enclosing surface in the far field. The radiated sound power of physical products can be validated by measuring the surface pressure or velocity and propagating outwards with near-field acoustical holography and again by integrating intensity in the far field. However, recent research using supersonic intensity (SSI) has sought to improve on these methods by implementing wavenumber truncation of the simulated or measured surface pressure and/or velocity and integrating on the surface of the structure with no need to propagate to the far field to obtain the radiated sound power. Unfortunately, SSI either overestimates or underestimates the sound power depending on the SSI method implemented and the frequency considered. This work presents an analysis of several SSI methods that have been proposed, identifies an SSI method that accurately calculates the radiated sound power, and gives supporting evidence for use of this method.