Accession Number:

ADA624737

Title:

Direct Measurements of Reynolds Stresses and Turbulence in the Bottom Boundary Layer

Descriptive Note:

Annual rept.

Corporate Author:

JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF MECHANICAL ENGINEERING

Personal Author(s):

Report Date:

2001-09-30

Pagination or Media Count:

11.0

Abstract:

The long-term goals are to a. Measure the Reynolds stresses, velocity profile, vorticity distribution and transport, dissipation rate, and turbulent spectra in the bottom boundary layer of the coastal ocean using Particle Image Velocimetry PIV. The objective is to obtain data that is free of wave contamination. b. Quantify the temporal variation of turbulent stresses, turbulence production, dissipation and spectra in relation to the oceanographic parameters that represent the local environment, such as waves, currents, vertical density gradient, internal waves and the nature of the water-sediment interface. The conclusions will quantify the relative importance of different mechanisms that control the flow and turbulence in the benthic boundary layer. c. Study the mechanisms and extent of sediment re-suspension process, while measuring the details of the evolving flow structure causing this entrainment. The data will enable us to determine whether sediment re-suspension is caused by large scale eddies, as small scale laboratory studies and atmospheric boundary layer data seem to indicate, shear caused by the mean flow over the bottom, or interaction of mean flow with ripples or other bottom features. d. Use oceanic PIV data for addressing Sub-Grid Scale Modeling issues for Large Eddy Simulation. e. Examine the structure of the flow, vertical vorticity transport, formation and upward migrations of large coherent vortex structures. Presently there is very little information on the dynamics and impact of large coherent structure in the bottom boundary layer on turbulence and sediment entrainment.

Subject Categories:

  • Physical and Dynamic Oceanography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE