Direct numerical simulation of turbulent Taylor-Couette flow with grooved walls

We present direct numerical simulations of Taylor-Couette flow with grooved walls up to inner cylinder Reynolds number of $Re_i=3.76\times10^4$, corresponding to Taylor number of $Ta=2.15\times10^9$. The simulations are performed at a fixed radius ratio $\eta=r_i/r_o=0.714$. The grooves are axisymmetric V-shaped obstacles attached to the wall...