Accession Number:

AD1173428

Title:

The Interaction of Wakes Generated by Submerged Propagating Objects with the Turbulent Subsurface Mixed Layer

Descriptive Note:

[Technical Report, Master's Thesis]

Corporate Author:

NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s):

Report Date:

2022-03-01

Pagination or Media Count:

49

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 object.

Subject Categories:

  • Undersea and Antisubmarine Warfare
  • Non-acoustic and Non-magnetic Submarine Detection

Distribution Statement:

[A, Approved For Public Release]