Acoustic Power Radiated from the Uniform Motion of a Source of Finite Size

A detailed analysis is presented for the acoustic power output and the angular distribution of such power emitted by the motion of a monopole sound source of finite size. The finite source continuously moves uniformly along a straight path, while its outer surface oscillates harmonically. A novel method of analysis is first briefly illustrated for a point source, and then it is quickly generalized for the finite source. The exact steady power output comes out expressed in terms of cosine-integral functions and logarithmic functions, for various values of the Mach number. The angular distribution of the power is obtained in exact analytic form via trigonometric functions, and also as a useful power series form. Pertinent graphs comparing the finite source to point source results are also given, as well as that for the spectrum of the finite source.