Advances in Turbulence VI pp 409-410 | Cite as
Experimental Study of Artificial Hairpin Vortices
Abstract
Several features of turbulence cannot be addressed properly by statistics: the dynamics remain out of reach. These dynamics are necessary to understand aspects like: ‘How are new vortices generated near the wall?’ or ‘Why do longitudinal riblets cause drag reduction?’ Therefore, coherent structures are attracting interest, especially hairpin vortices. A problem in the experimental study of coherent structures in a turbulent background is the fact that these structures do not reproduce in a turbulent flow nor is it easy to detect and define them. To overcome this, artificially created coherent structures in a laminar environment have been studied by several researchers. Special interest was concentrated on the interaction with the wall. It was found that new hairpin vortices could be generated by the interaction of the vortex and the wall (Haji-Haidari, 1990). In addition, Walker made simulations indicating the effect of the velocity profile on the shape of the vortex (Hon < Walker, 1987).
Keywords
Wind Tunnel Coherent Structure Drag Reduction Laminar Boundary Layer Hairpin VortexReferences
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