# Rotation

Multi-D models of the dynamical shear instability in a 20 solar mass star (Edelmann et al 2016, in prep.) using the SLH hydrodynamics code (Miczek, F.; Röpke, F. K.; Edelmann, P. V. F., 2015, A&A, 576A, 50M)

- 2D hydrodynamical simulations of dynamical shear
- 2D (equatorial plane) hydrodynamical simulations of dynamical shear. Panels show evolution of mean molecular weight (Abar, left) and Richardson number value (if Ri<1/4, then zone is unstable, right). The movie shows the dynamical shear instability developing after about 2000 seconds and its impact on Abar. The impact on the angular velocity (Omega) profile is similar.
- Time evolution of angular velocity (Omega) in 1D stellar evolution model
- Zones unstable to dynamical shear in 1D code are highlighted by red dots. The simulation domain corresponds to the interface between the carbon- and neon-rich layers post core oxygen burning.
- Time evolution of angular velocity (Omega) in 2D hydrodynamics simulation
- 2D hydrodynamics simulation to be compared to 1D stellar evolution model. In both 1D and 2D, the instability develops within an hour around radius, r=1.3e9 cm. We can see how the instability spreads out the initially steep omega gradient. Results will be published in Edelmann et al 2016 (in prep.)