Restricted Research - Award List, Note/Discussion Page

Fiscal Year: 2014

2045  The University of Texas at San Antonio  (23605)

Principal Investigator: Bhaganagar, Kiran

Total Amount of Contract, Award, or Gift (Annual before 2011): $ 254,417

Exceeds $250,000 (Is it flagged?): Yes

Start and End Dates: 7/15/13 <> 6/30/16

Restricted Research: YES


Department, Center, School, or Institute: Center for Simulation, Visualization and Real Time Prediction (SiViRT)  

Title of Contract, Award, or Gift: Research: Entrainment in Dense Currents over a Rough Bottom

Name of Granting or Contracting Agency/Entity: National Science Foundation

Program Title: none
CFDA Linked: Geosciences


We propose to study the dynamics controlling the entrainment in dense overflows over rough sloping bottom topography. Such currents are fundamental to the formation, movement, and distribution of the densest water in the ocean; a cornerstone of the thermohaline circulation. Even when resolving the overflows, coarse resolution global circulation and climate models cannot resolve the entrainment processes that are often parameterized. To date the entrainment parameterizations focused on the entrainment occurring at the interface between the dense and ambient waters. However, for shallow dense current the turbulent eddies generated by the bottom roughness may contribute to the entrainment of ambient waters. The proposed study will address this shortcoming with a combined laboratory and numerical study focused on quantify the entrainment due to bottom drag using different roughness elements (i.e. with different shape, vertical extent, density, and spatial distribution). The objectives of the proposed study are: (i) to quantify the relationship between entrainment and the ratio of the dense current depth and the bottom boundary layer thickness; (ii) to determine the influence of the vertical extent, density, and spatial distribution of the roughness elements on the thickness of the bottom boundary layer in which turbulent eddies are expected to develop; (iii) to establish a new universal entrainment parameterization which takes into account the contribution to entrainment due to bottom drag. The approach is process-oriented, using numerical models (DNS) and laboratory experiments that directly measure the entrainment occurring in a dense current flowing over a rough bottom slope both in rotating and non-rotating experiments.

Discussion: No discussion notes


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