Visualization of Flows in Curved Channels with aModerate or High Rotation Speed

[摘要] Flows in channels with streamwise curvature and spanwise rotation are visualized in termsof end-view near the exit of the test sections through injecting smoke into the flows. Two testsections are used, i.e. the rectangular channels with the aspect ratio of and 10, respectively.The work focuses on visualization of Dean and Coriolis vortices under the effects of secondaryinstabilities and flows in the region with a relatively high rotation speed. The resultsshow that the secondary instabilities cause the Dean and Coriolis vortices oscillating invarious forms and the flows at high rotation speeds are controlled by the secondary instabilitiesrather than the primary instability. In particular, the secondary instabilities lead theflows to be unsteady and turbulent somewhat like the bursting flow in the turbulent boundarylayers.

[学科分类] 力学，机械学