DOI: 10.1615/TSFP3
STUDY OF BOUNDARY LAYER FLOW IN ROTATING CURVATURE SYSTEM (THE OCCURRENCE AND GROWTH OF STREAMWISE VORTICES)
要約
The behavior of the boundary layer in rotating channels,
such as that in impeller passages of turbomachinery, 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 in the boundary layer, depending on its magnitude of the component normal to the wall boundary.
The purpose of the present study is to make clear experimentally the effects of Görtler type instability on the laminar boundary layer developing along the concave surface, focusing attention on transition process from laminar to turbulent state in the rotating system with streamline curvature. The longitudinal velocity and turbulent intensity have been measured near the concave surface in the channel whose radii of center line curvature is 1,OOO mm. When the Coriolis force
acts toward the concave wall due to the channel rotation, the occurrence of the Görtler vortices shifts upstream and the vortex structure is maintained in more downstream sections. In the earlier stage of vortex development an oscillation of flow was found to appear in the vortices despite of the rotating condition.