Measurements of Underwater Acoustic Intensity in the Nearfield of a Point Excited Periodically Ribbed Cylinder

Abstract

Vibrational energy from a machine mounted onto a hull propagates along the structure and radiates into the fluid. The propagating wavefield is shared between the structure and the fluid, so in order to understand the mechanisms by which energy propagates along the hull, it is necessary to investigate propagation in the fluid nearfield. To do this, grids of sound intensity measurements have been made on a representative structure: a periodically ribbed cylinder. The measurements are also intended to show how energy radiates to the far field, and the effects of the periodic ribs on the radiation. This work forms part of an overall study into the vibrational behaviour of a fluid loaded periodically ribbed cylinder. The measurement of the structural wavefield is reported in reference 1.