Bistatic Scattering from a Hemi-Spherically Capped Cylinder

Abstract

The bistatic scattering of an incident wave by a hemi-spherically capped cylinder is of particular interest because it has rarely been studied until the present day. The configuration of a hemi-spherically capped cylinder is similar to naval underwater weapons (submarines, mines, torpedos, etc.), but which is not exactly the same. This paper describes a novel laboratory experiment aimed at direct measurement of bistatic scattering by a hemi-spherically capped cylinder. Bistatic scattering by a hemi-spherically capped cylinder was measured in an acoustic water tank (5m long, 5m wide, 5m deep) using a high frequency projector (120kHz) and hydrophone. Measurements of monostatic scattering were also made under the same conditions. The bistatic scattering pattern by a hemi-spherically capped cylinder was measured against the incident angles (0 ∘ ,15 ∘ ,20 ∘ ,30 ∘ ,45 ∘ ,60 ∘ ,90 ∘ ) (0∘,15∘,20∘,30∘,45∘,60∘,90∘) in order to verify various scattering pattern characteristics by the change of incident angle. The results indicate that the bistatic scattering TS at a wide scattering angle is much stronger than the mono static scattering TS. In bistatic scattering, the forward scattering TS is significantly stronger than the backward scattering TS, and the forward scattering pattern is also broader. In case of seven incident angles, the maximum value of forward scattering TS is about 14dB stronger than that of backward scattering TS. It is also found that forward scattering varies with the incident angle of sound to a much less extent than backscattering, and it is not seriously affected by the incident angle. These features could be the advantages of using forward scattering for detecting underwater targets at long range and increasing detection area and probability.