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Full-Text Articles in Physics
Turbulent Mixing And Layer Formation In Double-Diffusive Convection: 3d Numerical Simulations And Theory, Erica Rosenblum, Pascale Garaud, Adrienne L. Traxler, Stephan Stellmach
Turbulent Mixing And Layer Formation In Double-Diffusive Convection: 3d Numerical Simulations And Theory, Erica Rosenblum, Pascale Garaud, Adrienne L. Traxler, Stephan Stellmach
Physics Faculty Publications
Double-diffusive convection, often referred to as semi-convection in astrophysics, occurs in thermally and compositionally stratified systems which are stable according to the Ledoux criterion but unstable according to the Schwarzschild criterion. This process has been given relatively little attention so far, and its properties remain poorly constrained. In this paper, we present and analyze a set of three-dimensional simulations of this phenomenon in a Cartesian domain under the Boussinesq approximation. We find that in some cases the double-diffusive convection saturates into a state of homogeneous turbulence, but with turbulent fluxes several orders of magnitude smaller than those expected from direct …
Numerically Determined Transport Laws For Fingering ("Thermohaline") Convection In Astrophysics, Adrienne L. Traxler, Pascale Garaud, Stephan Stellmach
Numerically Determined Transport Laws For Fingering ("Thermohaline") Convection In Astrophysics, Adrienne L. Traxler, Pascale Garaud, Stephan Stellmach
Physics Faculty Publications
We present the first three-dimensional simulations of fingering convection performed in a parameter regime close to the one relevant for astrophysics, and reveal the existence of simple asymptotic scaling laws for turbulent heat and compositional transport. These laws can straightforwardly be extrapolated to the true astrophysical regime. Our investigation also indicates that thermocompositional "staircases," a key consequence of fingering convection in the ocean, cannot form spontaneously in the fingering regime in stellar interiors. Our proposed empirically-determined transport laws thus provide simple prescriptions for mixing by fingering convection in a variety of astrophysical situations, and should, from here on, be used …