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Measurements of Skin Friction of the Compressible Turbulent Boundary Layer on a Cone with Foreign Gas InjectionMeasurements of average skin friction of the turbulent boundary layer have been made on a 15deg total included angle cone with foreign gas injection. Measurements of total skin-friction drag were obtained at free-stream Mach numbers of 0.3, 0.7, 3.5, and 4.7 and within a Reynolds number range from 0.9 x 10(exp 6) to 5.9 x 10(exp 6) with injection of helium, air, and Freon-12 (CCl2F2) through the porous wall. Substantial reductions in skin friction are realized with gas injection within the range of Mach numbers of this test. The relative reduction in skin friction is in accordance with theory-that is, the light gases are most effective when compared on a mass flow basis. There is a marked effect of Mach number on the reduction of average skin friction; this effect is not shown by the available theories. Limited transition location measurements indicate that the boundary layer does not fully trip with gas injection but that the transition point approaches a forward limit with increasing injection. The variation of the skin-friction coefficient, for the lower injection rates with natural transition, is dependent on the flow Reynolds number and type of injected gas; and at the high injection rates the skin friction is in fair agreement with the turbulent boundary layer results.
Document ID
20150020404
Document Type
Reprint (Version printed in journal)
Authors
Pappas, Constantine C. (NASA Ames Research Center Moffett Field, CA, United States)
Ukuno, Arthur F. (NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
November 3, 2015
Publication Date
May 1, 1960
Publication Information
Publication: Journal of Aerospace Sciences
Volume: 27
Issue: 5
Subject Category
Aerodynamics
Distribution Limits
Public
Copyright
Other