Shear-driven stratified turbulence at variable Prandtl number

ORAL

Abstract

We present a series of direct numerical simulations (DNS) of stratified turbulence, forced by vertical shear, at various Prandtl (Pr=1,7,50) and buoyancy Reynolds (Reb=30-1000) numbers. Variations in bulk turbulent quantities such as the dissipation rates of kinetic energy and scalar variance are discussed, and are related to changes in local flow structures across the parameter space. Particular attention is given to the influence of increasing Prandtl number, which generates increasingly fine density structures at small scales that in turn strongly influence the bulk mixing statistics. We briefly compare the results of our DNS to experimental measurements of shear-driven turbulence observed in the stratified inclined duct geometry, and discuss potential applications to shear-driven flows occurring in nature.

*This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. MMPC acknowledges funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) through RGPIN-2024-06184.

–

Presenters

  • Miles MP Couchman

    • York University

Authors

  • Miles MP Couchman

    • York University

  • Adrien Lefauve

    • Imperial College London

  • Stephen M de Bruyn Kops

    • UMass Amherst
    • Department of Mechanical and Industrial Engineering, University of Massachusetts Amherst