Investigation of shallow UNDEX in littoral ocean domain

Abstract

With recent delivery of littoral combat ships, the impact of operating in shallow or littoral ocean domain (LOD) during the duration of their life cycle is of interest, and a shock trial or hardening test and validation for this class is needed. For this study, the theories of underwater shock phenomena as applied within the boundaries of LOD, specific to the Eulerian fluid domain were conducted. The results of varying ocean depth show clear distinction in UNDEX characterization at depths shallower than 300ft. Varying charge size and depth showed that charge size of less than 300lbs of HBX-1 displayed a linear relationship while changing the charge depths to near water-air or water-bottom interface also resulted in amplified characteristics of UNDEX parameters. In addition, varying lateral boundary showed that as its distance is brought inside the radius of bulk cavitation, the UNDEX behavior also became increasingly chaotic due to similar effects seen in the shallower bottom depth. Lastly, adding blocked cells prior to a full scale coupled run showed that fluid behaves more erratically as these small rigid boundaries are situated within the radius of forming bulk cavitation.