75th Annual Meeting of the APS Division of Fluid Dynamics (November 20, 2022 — November 22, 2022)

V0121: Stratified Underflow and Kelvin-Helmholtz Instabilities

Authors

• Cary Troy, Purdue University, Lyles School of Civil Engineering
• Jeffrey Koseff, Stanford University, Department of Civil and Environmental Engineering

DOI: https://doi.org/10.1103/APS.DFD.2022.GFM.V0121

In this laboratory experiment, we release a dense saline fluid down a slope into a reservoir of fresh water.  Such "gravity currents" are ubiquitious in the environment, seen as fog creeping down the San Francisco hills or the daily sea breeze invading the streets of Chicago during summer.  Kelvin-Helmholtz instabilities form in the shear layer at the edge of the gravity current; these billows pair, grow, and collapse under their own weight, in turn mixing the two fluids.