Temperature Gradient Effects on Stator Boundary-Layer Stability in a Rotor–Stator Cavity

Abstract

A comprehensive approach, combining theoretical analysis and direct numerical simulation, is employed in this study to investigate the influence of temperature gradient on the stability phenomenon of the stator boundary layer in a rotor–stator cavity. In contrast to 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 layers of the stationary disk under operating conditions characterized by a Reynolds number of [Formula: see text]. The investigation reveals that this temperature gradient significantly affects the base flow and alters the instability governing the boundary-layer transition on the stationary disk. Specifically, the centrifugal buoyancy induced by the higher temperature on the stationary side weakens the spiral mode perturbations without inducing changes in the azimuthal wavenumber of the spiral mode. However, when the centrifugal buoyancy effect exceeds a certain threshold, it directly suppresses the generation of the spiral mode and induces the formation of low-radius circular waves, thereby promoting a more stable boundary layer. This research emphasizes the importance of considering temperature variations in the rotor–stator cavity for improved control of stability within the boundary-layer flow.