Abstract:
Acoustic waves scattered by an object in a stratified ocean are much different from acoustic waves in a homogeneous medium. In a stratified medium, the scattered energy is not spread out spherically. Therefore, the scattered far field consists of two components: the free-wave far field and the guided-wave far field. In many cases only the free-wave far field or only the guided-wave far field can be measured. This research concerns the problems of determining the shape of submersible from the incomplete far-field data. It has been found that the choice of incident waves is very important in determination of the shape of the unknown object from only the free-wave far field or only the guided-wave far field. Computational results demonstrate the importance of selection of incident waves. Sufficient conditions on incident waves are found for uniqueness in shape determination using incomplete data. [This research was supported in part by the NSF Grant No. BES-9402539, the UTC Summer Grant, and the China--Cornell Fellowship.]