https://doi.org/10.1103/PhysRevFluids.8.014502

Grace, A. P., Stastna, M., Lamb, K. G., Scott, K. A. (2023) Gravity currents in the cabbeling regime. Physical Review Fluids, 8, 014502. 25 pages. https://doi.org/10.1103/PhysRevFluids.8.014502

In this study, we present a series of simulations of gravity currents where ambient and intruding temperatures are on opposite sides of the temperature of maximum density. We use these simulations to describe how cabbeling (mixing of parcels of fluid that leads to a parcel of fluid that is denser) affects the evolution of gravity currents. We show that initially buoyant currents (called hypopycnal currents) undergo mixing in the body and tail region of the gravity current, which generates dense water from cabbeling. We investigate the maximum distance that the initial current progresses as a function of a parameter controlling the nonlinearity of the equation of state (referred to as ?). We find that the maximum distance that the current progresses is a nonlinear function of ?. For low ? hypopycnal currents reverse direction after they begin flowing, and cabbeling occurs over a limited spatial extent. As ? is increased, currents achieve a larger maximum distance of propagation, allowing the dense water formed by cabbeling to sink and form a secondary current along the bottom of the domain (called a hyperpycnal current). As we increase the parameter controlling the nonlinearity of the equation of state, the hyperpycnal current becomes much larger in scale. We discuss some general characteristics of the hyperpycnal current and highlight that once it forms, larger values of ? lead to a larger spatial extent of the current but narrower distributions of density and temperature.

https://doi.org/10.1103/PhysRevFluids.8.014502