STRATIFIED WAKE SIGNATURES GENERATED BY PROPAGATING SUBMERGED BODIES IN THE PRESENCE OF AN ACTIVE INTERNAL WAVE FIELD

This study characterizes the detectability of a stratified wake in the presence of background internal waves using numerical simulations. To achieve this, we conducted numerical simulations on Department of Defense high-performance computing systems using the Massachusetts Institute of Technology general circulation model, which we adapted for wake simulations. The internal waves were generated by forcing fluid motion over the seafloor with the frequency of semi-diurnal tides, while the topography is simulated based on a data-based stochastic model. By varying the magnitude of the forcing, we were able to perform a series of simulations with distinct initial intensities of the internal wave field in the range that reflects typical conditions in the ocean. The submerged body is characterized as an ellipsoid, whose depth and velocity were varied in order to analyze the strength of the signatures in relation to the background noise. Our analysis reveals limited influence of the wave field on the wake’s persistence. We also estimate the noise for the turbulent and thermal dissipation rates by taking a time average over a tidal cycle prior to the introduction of the submerged body. Using this noise, we show that, for our parameters, the wake from a submerged body would be undetectable after 30–60 minutes of passage. Finally, we observed that an interaction exists between the wake and the boundary layer that results in turbulence entrainment between both regions of the domain.

Department dc:contributor.department

Oceanography (OC)

Grantor dc:publisher

Monterey, CA; Naval Postgraduate School

Year dc:date.issued

2020

Author dc:creator

• Dougherty, Jack C.

Advisor dc:contributor.advisor

• Radko, Timour

Statement dc: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.

Handle dc:identifier.uri

https://hdl.handle.net/10945/65508

OAI identifier oai:identifier

oai:calhoun.nps.edu:10945/65508