Study on transition to turbulence of rotating-disk boundary layer in a rotor-stator cavity with temperature gradient

A comprehensive approach, combining theoretical analysis and large -eddy simulation, is employed in this study to investigate the influence of temperature gradient on the stability phenomenon of the von K & aacute;rm & aacute;n boundary layer in a rotor -stator cavity. Further from previous studies, a temperature term is introduced to account for centrifugal buoyancy within the cavity. The focus is on analyzing the transitional behavior and the effects of centrifugal buoyancy on the boundary layer of the rotating disk under operating conditions characterized by a Reynolds number Re = Omega(D) b(2) /v = 4 x 10(5) . The findings highlight that a temperature gradient between the stationary and rotating disks establishes enhanced flow circulation within the cavity. Consequently, this temperature gradient significantly influences the base flow and alters the critical Reynolds numbers governing the rotatingdisk boundary layer transition. Specifically, in the rotating -disk boundary layer, centrifugal buoyancy causes the premature breakdown of some inviscid modes, leading to an earlier transition to turbulence at lower Reynolds numbers. However, there exists a minimum critical Reynolds number in the rotating -disk boundary layer, beyond which the increase in centrifugal buoyancy does not further reduce the critical Reynolds number. This research emphasizes the importance of considering temperature variations in rotor -stator cavities for improved control of the stability within the rotating -disk boundary layer flow.