Acoustic wave diffraction by an ideal screen in a plane waveguide with thin elastic walls

Abstract

There is considered the diffraction problem for a plane waveguide with elastic walls. The boundary conditions yielding an identical mechanical mode of the waveguide walls and containing high order derivatives are not made specific. The natural acoustic wave from the waveguide depth is the field source. Diffraction of this wave by an ideal screen with a height half the waveguide width is studied. The screen is considered either absolutely rigid (Neumann condition), or absolutely soft (Dirichlet condition). Solutions are constructed for the case when plates capable only of bending vibrations are the walls and the boundary-contact conditions needed for unique solvability of the problem /1/ are selected here so that they describe the junction of the screen and one of the plates, are constructed as examples. There is also obtained a solution for the case of impedance conditions on the waveguide walls. A similar wave diffraction problem by a diaphragm in a waveguide with ideal walls (absolutely soft or absolutely rigid) but without matrix nature, is examined in /2/.