Princeton Center for Heliophysics Seminar

Stellar fluids have a low Prandtl number, which distinguishes them from geophysical fluids by allowing for the existence of turbulence regimes that are diffusive yet non viscous. In this talk I will present recent results demonstrating the existence of several regimes of stratified turbulence in low Prandtl number fluids, using asymptotic analysis validated by direct numerical simulations. One of the major outcomes of this research is a map of parameter space for the turbulent diffusivity of a passive scalar and for the buoyancy flux, as a function of the Prandtl number of the fluid, and of the Reynolds number and Froude number of the large-scale flow driving the turbulence. This work is in collaboration with Greg Chini, Kasturi Shah, Laura Cope, and Colm-cille Caulfield.