EFFICIENCY OF SOUND FIELD EXCITATION IN AN ELASTIC WAVEGUIDE

Abstract

Based on a comparative analysis of sound generation by a finite-sized source in an unbounded acoustic medium and forced oscillations in a semi-infinite elastic waveguide, fundamental differences in the efficiency of wave field excitation have been established. The radiation efficiency of the acoustic source was evaluated by analyzing the active and reactive components of the instantaneous power flow. It is demonstrated that, for an elastic waveguide, the active power flow component exhibits a resonant behavior, reaching its peak at the edge resonance frequency. At this frequency, the reactive component vanishes, resulting in maximum radiation efficiency. Furthermore, the reactive component of the instantaneous power flow displays two local maxima, where its magnitude significantly exceeds that of the active component.