The challenging task of 'properly' tripping the boundary layer near the leading edge of an airfoil experiencing compressible dynamic stall has been addressed. Real-time interferometry studies have been conducted on an oscillating airfoil undergoing compressible dynamic stall at free stream Mach numbers of 0.3 and 0.45, by separately placing five different trips of varying sizes. The trip heights ranged from 40 to 175; the estimated boundary layer thickness was 60 at the point of flow separation at a Mach number of 0.3. Quantitative analysis of the interferograms showed that the laminar separation bubble characteristic of low Reynolds number airfoil flows was still present with the smallest trip and premature dynamic stall occurred with the largest trip. A roughness element extending between 0.5% chord to 4% chord from the leading edge and of a height comparable to the boundary layer thickness at the point where the dynamic stall vortex forms was found to be the 'right' trip.
Boundary-Layer-Tripping Studies of Compressible Dynamic Stall Flow
1996
10 pages
Report
No indication
English
Fluid Mechanics , Aerodynamics , Compressible flow , Stalling , Flow separation , Boundary layer flow , Pressure gradients , Reprints , Real time , Turbulence , Vortices , Flow fields , Leading edges , Mach number , Unsteady flow , Boundary layer transition , Free stream , Laminar flow , Pressure distribution , Dynamic pressure , Reynolds number , Laminar boundary layer
Boundary Layer Tripping Studies of Compressible Dynamic Stall Flow
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