Experiments in Sound and Structural Vibrations Using an Air-Analog Model Ducted Propulsion System

摘要

The prediction of the radiated acoustic signature of underwater structures has been and will continue to be of great importance for the Navy. New and innovative designs of maneuvering and propulsion systems present challenging problems for the prediction of radiated acoustics. The present research focused on the development of structural acoustic experiments that use air as the working fluid. The test specimens were designed using very light weight structures such that the fluid loading effects would be non-negligible, and in some cases dominant. A number of configurations have been investigated, including flat membranes, rib-stiffened cylindrical structures, and a ducted rotor with elastic shell. The ducted rotor facility is part of a continuing effort involving the effects of inlet distortion on the elastic shell vibrations. A substantial database of flow field, acoustic, and vibration measurements has resulted. The data show a significant sensitivity of the structural vibration to the spatial distribution of the acoustic sources.