|Date: Friday, November 03, 2017
Location: 1084 East Hall (3:00 PM to 4:00 PM)
Title: Turbulence and mixing in stably-stratified shear flows
Abstract: Oceanic overflows, wind-driven thermocline layers and river estuaries are important geophysical examples of stably-stratified shear flows. Although field measurements are an essential tool in characterizing these complex flows, a combination of laboratory experiments, numerical simulations, and theory is crucial for interpreting the results. We realize a turbulent stably-stratified shear flow in the laboratory and use modern experimental techniques of laser-induced fluorescence and particle image velocimetry to examine the properties of these flows. The controlling dimensionless number that characterizes the competition between shear and buoyancy is the Richardson Number Ri but it is very challenging to relate experimental measurements of Ri with the corresponding parameter in numerical simulations and linear theory. Using conditional averaging, we show how results can be interpreted in such a manner to be consistent with the linear stability results of Miles and Howard. Our analysis suggests a dynamical way to think about evolving mixing layers with potential application to real world oceanographic situations.
Speaker: Robert Ecke
Institution: Los Alamos National Lab
Event Organizer: Charlie Doering firstname.lastname@example.org