Physical Oceanography & Meteorology Seminar
Marek Stastna
University of Waterloo
Title:
“That other nonlinearity: how the nonlinear equation of state modifies winter time dynamics in Canadian lakes”
Location:
Riley Room O3652
LSC, Oceanography wing
Abstract:
It is well known that the material derivative leads to a host of nonlinear behaviours in fluid flows. From the steepening of waves as they shoal, to the turbulent cascade that controls the exchange of momentum across scales the effects of this simple to write down bit of mathematics are readily observable in the field. There is a second, weaker nonlinearity in the governing equations that manifests in certain special situations. This nonlinearity is contained in the buoyancy term, through the equation of state that relates density to the temperature, salinity and pressure. I will present examples of the manifestations of this nonlinearity in wintertime freshwater lakes. I will demonstrate that in this quiet regime the nonlinearity is essential, and leads to strange physics and dynamics that remains only partially understood. I will present results of large direct numerical simulations, as well analysis tools that have been developed to track some of these phenomena. I will conclude with some thoughts about how turbulence should be parametrized in these regimes.
There will be pizza!
If anyone would like to meet with Marek while he is in town, please contact Ruth at Ruth.Musgrave@dal.ca.
The next POMS seminar will be on October 9th, from our very own Hana Hourston.
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