Publication:
Boundary Layer Tripping Studies of Compressible Dynamic Stall Flow

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Authors
Chandrasekhara, M.S.
Wilder, M.C.
Carr, L.W.
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Abstract
The challenging task of properly tripping the boundary layer of a leading-edge-stalling airfoil experiencing compressible dynamic stall at Reynolds numbers between 3.6 X 10⁵ and 8.1 X 10⁵ has been addressed. Real-time interferometry data of the flow over an oscillating airfoil have been obtained at freestream Mach numbers of 0.3 and 0.45. The airfoil was tripped by separately placing five different trips of varying lengths near the leading edge. The trip heights ranged from 40 to 175 µm. The resulting flow and airfoil performance were evaluated using the criteria of elimination of the laminar separation bubble that otherwise forms, delay of dynamic stall onset to higher angles of attack, and production of consistently higher suction peaks. Quantitative analysis of the interferograms showed that the laminar separation bubble was still present with the smallest trip and premature dynamic stall occurred with the largest trip. The right trip was determined to be a distributed roughness element extending from 0.5 to 3% chord. Its height was found to compare reasonably with the airfoil boundary-layer thickness at the dynamic stall vortex formation angle of attack, at a location slightly upstream of the vortex origin in the adverse pressure gradient region.
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(AIAA Paper 94-2340), AIAA Journal, Vol. 34, No. 1, Jan. 1996, pp. 96-103.
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ARO-MIPR-125-93
AFOSR-MIPR-93-0003
U.S. Naval Postgraduate School
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ARO-MIPR-125-93
AFOSR-MIPR-93-0003
U.S. Naval Postgraduate School
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8 p.
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M.S.Chandrasekhara, M.C.Wilder, and L.W.Carr, モBoundary Layer Tripping Studies of Compressible Dynamic Stall Flowヤ, (AIAA Paper 94-2340), AIAA Journal, Vol. 34, No. 1, Jan. 1996, pp. 96-103.
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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