| Abstract: | The acoustic field of a source moving at a subsonic velocity in a regular waveguide with perfectly reflecting boundaries is considered. The acceleration of the source is assumed to be small. In a moving coordinate system, the asymptotics of the wave field is obtained. This asymptotics is inapplicable near the critical cross sections, for which the Doppler frequency of the source coincides with the frequency of the waveguide mode under consideration. It is demonstrated that, in this case, the wave field can be represented locally by a special type of integral, which is analyzed by the saddle-point method.Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 239, 1997, pp. 71–78.This work was supported in part by the Russian Foundation for Basic Research under grant 95-01-01285a. |
