Technical Abstract Bulletin


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Measurements of Aerodynamic Heat Transfer and Boundary-layer Transition on a 10° Cone in Free Flight at Supersonic Mach Numbers Up to 5.9


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Abstract: Aerodynamic heat-transfer measurements were at six stations on the 40-inch-long 10° total-angle conical nose of a rocket-propelled model which was flight tested at Mach numbers up to 5.9. The range of local Reynolds number was from 6.6 x 106 to 55.2 x 106. Laminar, transitional, and turbulent heat-transfer coefficients were measured, and, in general, the laminar and turbulent measurements were in good agreement with theory for cones. Experimental transition Reynolds numbers varied from less than 8.5 x 106 to 19.4 x 106. At a relatively constant ratio of wall temperature to local static temperature near 1.2, the transition Reynolds number increased from 9.2 x 106 to 19.4 x 106 as Mach number increased from 1.57 to 3.38. At Mach numbers near 3.7, the transition Reynolds number decreased as the skin temperature increased toward adiabatic wall temperatures.










The Effect of Pressure Gradients on Transition Zone Length in Hypersonic Boundary Layers


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Boundary layer transition was measured in zero, favorable, and adverse pressure gradients at Mach 8 using heat transfer. Models consisted of 7 degrees half angle forecones 0.4826 m long, followed by flared or ogive aft bodies 0.5334 m long. The flares and ogives produced constant pressure gradients. For the cases examined, favorable pressure gradients delay transition and adverse pressure gradients promote transition, but transition zone lengths are shorter in favorable pressure gradient. Results of the effect of adverse pressure gradient on transition zone lengths were inconclusive.







NASA Scientific and Technical Reports


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