Experimental Study of the Stability of a Travelling Roll System in a Rotating Disk Flow

Abstract

Several studies have already adressed the problem of the stability of the two control parameters flow of a viscous fluid driven between a rotating and a stationary disk, when both the aspect ratio and the Reynolds number can be varied. The aspect ratio is defined as h/R where h is the axial distance between the two parallel disks and R their radius, and the Reynolds number is Re = ΩR²/v where Ω is the angular velocity of the rotating disk and v the kinematic viscosity of the working fluid. The experiments of San’kov and Smirnov (1984), Itoh (1988) or Sirivat (1991) revealed the existence of various bifurcation sequences for the transition to turbulence, depending on the considered aspect ratio, when the Reynolds number is increased. Recently, by exploring the two dimensionnal control parameter space (h/R, Re), we have determined the whole experimental transition diagram of this rotating disk flow (Schouveiler et al., 1996, and Schouveiler, 1998) which completes the previous experimental studies and summarizes the regimes of the flow and the bifurcation sequences.