Sound excitation by a pulse source in a pipe

Acoustic wave excitation by a pulse source in a pipe with rigid walls filled with moving liquid is considered. Formulas for acoustic fields and radiated power are derived. It is found that the radiation output of an acoustic monopole is maximum when it is located near the waveguide wall, and minimum when it is at the waveguide axis. Effects of medium motion and pulse duration on the radiation spectrum and the total radiated energy are studied. Algorithms for estimating these energy characteristics are presented.