ASA 124th Meeting New Orleans 1992 October

3aSA10. The effect of irregularity on the scattering of acoustic waves from a ribbed plate.

Douglas M. Photiadis

Naval Res. Lab., Washington, DC 20375-5000

The scattered field from an irregularly ribbed fluid-loaded plate is ``measured'' using numerical simulations. The diffuse field scattered by the irregularity exhibits strong coherent features in the far-field scattering pattern associated with phase matching to locally propagating Bloch waves on the structure. These features are also apparent in the scattering from finite periodic arrays, but are strongly enhanced by irregularity. Some examples of the behavior of the system are presented and the scaling of the cross section with the number of scatterers and irregularity is determined.