Figure 2: Iso-contours of the instantaneous axial velocity field at the inner and outer walls obtained by the eddy-resolving IIS-RSM in the concentric annulus with inner-cylinder rotation at N=0.858 (left) and outer cylinder rotation at N=1 (right). The colors denote the value from 0.1(blue) to 0.6(red), representing the instantaneous axial velocity at the inner and outer walls at y+ ≈ 5 obtained by the present eddy-resolving IIS-RSM model.