The Effect of Uniformly Distributed Roughness on Turbulent Skin Friction Drag at Supersonic Speeds

Citation

Goddard, Frank Eber (1957) The Effect of Uniformly Distributed Roughness on Turbulent Skin Friction Drag at Supersonic Speeds. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/BA5G-7H43. https://resolver.caltech.edu/CaltechETD:etd-07132004-115342

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. An experimental program was carried out in the 18 x 20-inch supersonic wind tunnel of the Jet Propulsion Laboratory at the California Institute of Technology to determine the effect of uniformly distributed sand-grain roughness on the skin friction drag of a body of revolution for the case of a turbulent boundary layer. The Mach-number range covered was 1.98 to 4.54 and the Reynolds number varied from about [...] to [...]. Some data were also obtained at a Mach-number of 0.70. At speeds up to a Mach number of 5 and for roughness sizes such that the quadratic resistance law holds, the compressibility effect is indirect and the skin friction drag is a function only of the roughness Reynolds number, [...], just as in the incompressible case. The critical roughness below which the surface is hydraulically smooth is [...] and this is equal to the thickness of the laminar sublayer for a smooth surface for both compressible and incompressible flows. Over the range of roughness sizes considered here there appears to be no wave drag associated with the drag due to roughness. The shift in the turbulent velocity profile [...] for a rough surface at supersonic speeds is a function only of the roughness Reynolds number, [...], and quantitatively follows identically the same law as in the incompressible case.

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