Astrophysical Fluid Dynamics via Direct Statistical Simulation

TL;DR

This paper introduces Direct Statistical Simulation (DSS), a new computational approach for modeling the statistical properties of astrophysical fluid flows, focusing on problems where flow details are less important than their overall statistical behavior.

Contribution

The paper presents DSS as a novel method tailored for astrophysical fluids, with a spectral implementation for spherical surfaces, applicable to hydrodynamics and MHD.

Findings

Demonstrated DSS on hydrodynamics and MHD on a rotating sphere

Showed DSS effectively captures statistical properties of astrophysical flows

Discussed potential extensions and applications of DSS

Abstract

In this paper we introduce the concept of Direct Statistical Simulation (DSS) for astrophysical flows. This technique may be appropriate for problems in astrophysical fluids where the instantaneous dynamics of the flows are of secondary importance to their statistical properties. We give examples of such problems including mixing and transport in planets, stars and disks. The method is described for a general set of evolution equations, before we consider the specific case of a spectral method optimised for problems on a spherical surface. The method is illustrated for the simplest non-trivial example of hydrodynamics and MHD on a rotating spherical surface. We then discuss possible extensions of the method both in terms of computational methods and the range of astrophysical problems that are of interest.