THE INTERACTION OF WAKES GENERATED BY SUBMERGED PROPAGATING OBJECTS WITH THE TURBULENT SUBSURFACE MIXED LAYER

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Authors
Lee, Hwanhee
Subjects
anti-submarine warfare
turbulent wakes
the interaction of wakes
submerged propagating objects
subsurface mixed layer
surface thermal signatures
high-resolution numerical simulations
submerged body
SB
mixed layer depth
MLD
Advisors
Radko, Timour
Date of Issue
2022-03
Date
Publisher
Monterey, CA; Naval Postgraduate School
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Abstract
In this study, the numeral simulations were conducted using OpenFOAM to investigate how changes in mixed layer depth (MLD), speed and depth of a submerged body (SB) affect observable signatures of the SB moving beneath a mixed layer. We studied the effect of these factors on both surface and interior temperature perturbations. This study has shown that the wake generated by an SB in the presence of a mixed layer has a greater surface temperature signature than that without it. Furthermore, the deeper the MLD, the greater the thermal signal. This is because when the mixed layer is present, the region is more weakly stratified than it would be without a mixed layer, and the reduced buoyancy force permits fluid entering the mixed layer to penetrate farther. Through variation in speed and depth of SB, we found that faster SB results in stronger turbulence, greater temperature change, and larger areas of surface wake penetration. Also, deeper SB motion levels result in greater surface temperature signals by dredging up colder water from the SB surroundings to the surface. This study confirmed the possibility of detection through surface temperature changes formed by wakes inevitably generated by submerged objects.
Type
Thesis
Description
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Department
Oceanography (OC)
Organization
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Sponsors
Office of Naval Research, Washington, DC 20375
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Distribution Statement
Approved for public release. Distribution is unlimited.
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