**Contact Info**

Department of Applied Mathematics

University of Waterloo

Waterloo, Ontario

Canada N2L 3G1

Phone: 519-888-4567, ext. 32700

Fax: 519-746-4319

PDF files require Adobe Acrobat Reader

Wednesday, December 14, 2022 1:00 PM EST

MS Teams: Please email amgrad@uwaterloo.ca for the meeting link

Jesse Legaspi | Applied Mathematics, University of Waterloo

Exploration of the full nonlinear wave/potential-vortex mode decomposition of stratified turbulence DNS

Fluid motion in stratified turbulence is comprised of internal gravity waves and quasi-horizontal vortices. To fundamentally understand the dynamics of stratified turbulence, the two modes can be studied for their individual behaviour and the nature of their interactions. This necessitates some means of separating stratified turbulence into their wave mode and vortex mode. The wave/potential-vortex decomposition in Staquet and Riley (1989) (hereafter, SR89) is one such method developed for purely stratified flows with finite Froude number.

In the proposed project, the SR89 decomposition is implemented and includes a filtering method that preconditions the field variables, which removes problematic small-scale fluctuations. The method is examined for its convergence and the filter is analyzed for its effect on the kinetic energy spectra for both wave and potential-vortex modes. The examined simulations are configured so that kinetic energy spectra of both modes can be decently analyzed as the buoyancy Reynolds number and the stratification strength are varied. Next, as an important characterizing property, the potential vorticity will be studied by means of a spectral budget equation obtained for the potential enstrophy, a related quantity. Through the SR89 decomposition method, the potential-vortex mode is easily accessible and facilitates this analysis. Lastly, we make an excursion to very small length scales to study intermittency in stratified turbulence. Small-scale turbulence that the SR89 decomposition filters out can be retained and analyzed, primarily by examining distribution plots and computing statistical moments.

Event tags

**Contact Info**

Department of Applied Mathematics

University of Waterloo

Waterloo, Ontario

Canada N2L 3G1

Phone: 519-888-4567, ext. 32700

Fax: 519-746-4319

PDF files require Adobe Acrobat Reader

University of Waterloo

University of Waterloo

43.471468

-80.544205

200 University Avenue West

Waterloo,
ON,
Canada
N2L 3G1

The University of Waterloo acknowledges that much of our work takes place on the traditional territory of the Neutral, Anishinaabeg and Haudenosaunee peoples. Our main campus is situated on the Haldimand Tract, the land granted to the Six Nations that includes six miles on each side of the Grand River. Our active work toward reconciliation takes place across our campuses through research, learning, teaching, and community building, and is co-ordinated within the Office of Indigenous Relations.