Investigation of boundary-layer transition on 10 degree cone in Langley 4- by 4-foot supersonic pressure tunnel at Mach numbers of 1.41, 1.61, and 2.01

Author / Creator

Sinclair, Archibald R., author

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Online

Summary

An investigation has been made to determine the transition Reynolds numbers on a 10 degree cone in the Langley 4- by 4-foot supersonic pressure tunnel at Mach numbers of 1.41, 1.61, and 2.01 and ov...

An investigation has been made to determine the transition Reynolds numbers on a 10 degree cone in the Langley 4- by 4-foot supersonic pressure tunnel at Mach numbers of 1.41, 1.61, and 2.01 and over a Reynolds number range from about 800,000 to 9,500,000 per foot. The results indicate that, on the average, the transition Reynolds numbers for a smooth cone increased with tunnel stagnation pressure from about 7,000,000 at a test Reynolds number of 4,000,000 per foot to approximately 8,000,000 at a test Reynolds number of 9,000,000 per foot for all test Mach numbers. There was no effect of Mach number on transition Reynolds number. The results also indicated that the transition point was unsteady and tended to oscillate approximately plus or minus 10 percent about the mean value of transition Reynolds number.

A single-element two-dimensional-surface roughness of one layer of 1/2-inch-wide and 0.003-inch-thick cellulose tape caused a larger decrease in transition Reynolds number than was experienced in low-speed or in other supersonic wind-tunnel investigations. The parameter of comparison was the ratio of transition Reynolds nuniberfor the rough cone to that for the smooth cone for the same value of roughness height to boundary-layer displacement thickness at the roughness station.

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