Multiple states in turbulent plane Couette flow with spanwise rotation

Turbulence is ubiquitous in nature and engineering applications. Although Kolmogorov's (C. R. Acad. Sci. URSS, vol. 30, 1941a, pp. 301-305; Dokl. Akad. Nauk URSS, vol. 30, 1941b, pp. 538-540) theory suggested a unique turbulent state for high Reynolds numbers, multiple states were reported for several flow problems, such as Rayleigh-Benard convection and Taylor-Couette flows. In this paper, we report that multiple states also exist for turbulent plane Couette flow with spanwise rotation through direct numerical simulations at rotation number R-o = 0.2 and Reynolds number R-ew = 1300 based on the angular velocity in the spanwise direction and half of the wall velocity difference. With two different initial flow fields, our results show that the flow statistics, including the mean streamwise velocity and Reynolds stresses, show different profiles. These different flow statistics are closely related to the flow structures in the domain, where one state corresponds to two pairs of roll cells, and the other shows three pairs. The present result enriches the studies on multiple states in turbulence.