Sensor number requirements for sound power prediction using two different mode decomposition methods

Normal velocity distribution on the vibrating surface can be used for sound radiation prediction, where the normal velocity distribution is commonly reconstructed by using the velocities measured at some individual locations on the surface. In this communication, by considering the precision of the mode amplitude estimation, the number requirements of velocity sensors are compared between using the vibration mode decomposition method (VMD) and the radiation mode decomposition method (RMD) for sound power prediction. For low damped baffled simply supported rectangular plates, it is shown that employing RMD requires fewer sensors below the first resonance frequency than employing VMD, while employing VMD at structural resonance frequencies requires fewer sensors than that employing RMD.