Investigation of an explicitly modeled solid ocean floor on a shallow water UNDEX event
Loading...
Authors
Walters, Adam P.
Subjects
Advisors
Kwon, Young W.
Date of Issue
2011-09
Date
Publisher
Monterey, CA; Naval Postgraduate School
Language
Abstract
Current practices for modeling the ocean floor in underwater explosion simulations call for application of an inviscid fluid with soil properties. A method for modeling the ocean floor as a Lagrangian solid, vice an Eulerian fluid, was developed in order to determine its effects on underwater explosions in shallow water using the DYSMAS solver. The Lagrangian solid bottom model utilized transmitting boundary segments, exterior nodal forces acting as constraints, and the application of prestress to minimize any distortions into the fluid domain. Elastic materials were used, though multiple constitutive soil models can be applied to improve the accuracy. This method is unable to account for soil cratering effects, however it provides the distinct advantage of modeling contoured ocean floors such as dredged channels and sloped bottoms absent in Eulerian formulations. The dynamic loading effects of the investigated bottom contours were found to be negligible in the analyzed cases as a result of the bulk cavitation zone which dominates the chosen fluid field and serves as a buffer to the target. In addition to its utility in bottom modeling, implementation of the non-reflecting boundary along with realistic material models can be used to drastically reduce the size of current fluid domains.
Type
Thesis
Description
Series/Report No
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Funder
Format
xviii, 114 p. : ill. ;
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.