Authors: Y.-N. Young; N.N. Mansour; A. Kosovichev; M. Miesch
Affiliation: Center for Turbulence Research; NASA Ames Research Center; Stanford
University; National Center for Atmospheric Research, High Altitude Observtory
Understanding the complex dynamics in the solar convection zone is crucial for gaining insight into the solar dynamo problem. Many solar observations have generated revealing data with great details of large-scale motions in the solar convection zone. For example, a strong differential rotation is observed: the angular rotation is observed to be faster at the equator than near the poles, not only near the solar surface, but also deep in the convection zone. On the other hand, due to the wide range of dynamical scales of turbulence in the solar convection zone, both theory and simulation have limited success. Thus, cutting edge solar models and numerical simulations of the solar convection zone have focused more narrowly on few key features of the solar convection zone. We use Large Eddy Simulation methodology to simulate the solar convection zone. In our approach we resolve the large eddies and simulate the effects of the small eddies on the large eddies using a Smagorinsky type model. We modify the Smagorinsky-Lilly model that was developed for stratified flows to take into account some of the effects of rotation on turbulence. This new model was implemented into the ASH (anelastic spherical harmonic) code. We find that the model reproduces the differential rotation observed by helioseismology and simulated by various authors. Our results show more radial flow structures than observed with mixing-length type models. We compare our results to previous simulations, showing the effect of the model on differential rotation and meridional flows.