(a) WTG operated at optimal tip speed ratio
(b) Stationary disk
Figure 12: Spanwise profiles of the time-averaged streamwise ( ) velocity at (( ) = (0, 0, 0) indicates the center of the rotor; see Figure 3). The profiles are observed at (○), (□) and (), where is the rotor diameter. The streamwise velocity and the spanwise position on the -axis are normalized by the uniform inflow velocity, , and , respectively. The -coordinate of the rotor is shown with arrows.