Reply by Author to K. F. Stetson

Abstract

Stetson, K. F., Nosetip Bluntness Effects on Cone Frustum Boundary-Layer Transition in Hypersonic Flow, AIAA Paper 831763, July 1983. Reshotko, E. and Khan, M. M. S., ''Stability of the Boundary Layer on a Blunted Plate in Supersonic Flow, presented at IUTAM Symposium on Laminar-Turbulent Transition, Stuttgart, FRG, Sept. 1979. Wright, R. L. and Zoby, E. V., Flight Boundary-Layer Transition Measurements on a Slender Cone at Mach 20, AIAA Paper 77719, June 1977. Stetson, K. F., Thompson, E. R., Donaldson, J. C., and Siler, L. G., Laminar Boundary-Layer Stability Experiments on a Cone at Mach 8, Part 2: Blunt Cone, AIAA Paper 84-0006, Jan. 1984. Stetson, K. F., Thompson, E. R., Donaldson, J. C., and Siler, L. G., Laminar Boundary-Layer Stability Experiments on a Cone at Mach 8, Part 1: Sharp Cone, AIAA Paper 83-1761, July 1983. via the change in the boundary-layer edge conditions through the ''entropy wake generated by the curved bow shock. This change of inviscid flow characteristics is well predicted by the embedded Newtonian theory,' as has been demonstrated recently. Changes in wall temperature and unit Reynolds number do, of course, affect the viscous flow characteristics for both the sharp and the blunted cone. However, the effect of a geometric change from a sharp to a blunted cone is still inviscid in nature. Keeping the above in mind, a careful reading of Ref. 1 will provide all of the answers to the questions raised by Mr. Stetson, keeping in mind that the ratio dN/dB tells whether the conic frustum is long enough to experience the inviscid flow effects imprinted on the boundary layer by the entropy wake.