Monday  |  Lakeshore A  |  03:00 PM–03:20 PM

#19262, Mitigating Pressure Pulses from Underwater Implosion using External Rings

An experimental study of the underwater collapse of cylindrical shells was conducted in an attempt to mitigate the pressure pulses emitted. This study explored three variations of an externally fitted device, called a ring, located near a sealed implodable volume which was brought to instability hydrostatically within a pressure vessel, simulating a free-field environment. This ring surrounded a portion of the implodable volume and only made contact with the implodable after it reached critical instability and began to deform. High-speed stereo photography coupled with 3D digital image correlation (DIC) provided full-field displacement histories of the implodable during the event. High frequency response dynamic pressure transducers placed at several locations around the shroud captured emitted pressure histories. The effects of varying ring diameter, shape, and placement along the implodable volume on the pressure signatures emitted by the implosion of thin metallic cylindrical shells were experimentally investigated. The rings mitigated the emitted pressure history by up to 60% in the underpressure region, and up to 80% in the overpressure region. The diameter of the ring affected the emitted pressure signature, with mitigation effects improving as the diameter approaches that of the incipient deformation of the implodable. The collapse shape of the implodable is governed by the ring diameter, with mode-2 shapes at largest ring diameters, and c-shape collapse at the smallest of ring diameters.

Victoria Reilly   University of Rhode Island
Dillon Fontaine   University of Rhode Island
Arun Shukla   University of Rhode Island