DOI: 10.1615/TSFP4
STUDY OF BOUNDARY LAYER FLOW IN ROTATING CURVATURE SYSTEM
(The effects of system rotation and streamline curvature on the secondary instability of the Görtler vortices)
要約
The behavior of the boundary layer in rotating channels, such as those in impeller passages of turbomachines, is dominantly influenced by the centrifugal and Coriolis forces due to the wall curvature and system rotation, respectively. The resultant force may promote or suppress the instability of the flow in the boundary layer, depending on the direction and magnitude of the component normal to the wall boundary.
The purpose of the present study is to make clear experimentally the effect of the Görtler type instability on a laminar boundary layer and the transition process. The longitudinal changes of velocity and turbulent intensity have been measured near the concave surface. When the Coriolis force whose magnitude exceeds to the centrifugal one acts opposite to the centrifugal force, the generation of the Görtler vortices is suppressed. When the resultant force acts toward the concave surface, the Görtler vortices are generated and develop downstream, resulting in the secondary instability, which leads the boundary layer into a turbulent state.