A Flow Visualization Study of Acoustically Enhanced Hairpin Vortices
Abstract
For many years the turbulent boundary layer was thought to be composed of totally chaotic and random eddies. However, recent work has shown that a very organized array of structures exist in this regime. These structures, named hairpin, horseshoe or V-inversed shaped vortices, compose a major portion of the turbulent boundary layer and may be responsible for the increased heat transfer seen in turbulent regimes. The hairpin vortex is a vortex line that has been lifted off of the surface and through mutual induction of its legs forms a loop. This loop is composed of two counter-rotating legs, oriented at 45 degrees to the wall, with a head that joins the two legs together. These legs act like tornados sweeping along the wall. They transport air adjacent to the wall up through the legs and into the head. Research at the University of Washington has shown that this 'tornado effect' increased the heat flux away from the wall. If this capability can be harnessed and enhanced, the effects of film cooling in turbine Engines can be dramatically increased.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1993
- Accession Number
- ADA275467
Entities
People
- Stephen A. Whyte
Organizations
- Air Force Institute of Technology