An experimental investigation of laminar boundary-layer transition on a sharp, 10° total angle, insulated cone at zero yaw was conducted in the AEDC-VKF12-in. and 40-in. supersonic wind tunnels at freestream Mach numbers from 3 to 6. This research was directed toward denning the relationship between the aerodynamic noise disturbances and boundary-layer transition Reynolds numbers [(Ret)d] in high-speed wind tunnels and has extended previously published planar results to include axisymmetric models. A significant increase in (Ret)s with increasing tunnel size (similar to the planar results) is shown to exist. Sharp cone transition Reynolds numbers from eleven facilities (12-54 in.) for freestream Mach numbers from 3 to 14 and a unit Reynolds number per inch range from 0.1 X 10 6 to 1.2 X 10 6 have been correlated using aerodynamic-noise-transition parameters. A quantitative correlation of the ratio between cone and planar (Re t )d values has been developed which demonstrates a strong Mach number dependence and also indicates a variation with tunnel size and unit Reynolds number.
Nomenclatureb = model nose bluntness, in. CF = mean turbulent skin-friction coefficient (tunnel wall) c = tunnel test section circumference, in. d = tunnel test section circumference of 12-X 12-in. tunnel (ci = 48 in.) I = model axial length, in. l m = axial distance from tunnel throat to model nose, in. l r -axial distance from tunnel throat to wall boundarylayer rake, in. M = Mach number p = surf ace probe Pitot pressure, psia PC -cone surface static pressure, psia PO = tunnel stilling chamber pressure, psia po' = total pressure downstream of a normal shock wave at freestream conditions, psia poo = freestream static pressure, psia p = root-mean-square of pressure fluctuation, psia #00 = freestream dynamic pressure, psia q = heat-transfer rate, Btu/f t 2 -sec (Rei)s = transition Reynolds number (based on local conditions), (Re t )s = (Re/m.)sx t Res or = inviscid flow local surface unit Reynolds number (Re/m.)s per in., Us/vs Re^ or = freestream Reynolds number per in., U^/v( Be/in.). T = static temperature, °R and/or °F To = tunnel stilling chamber total temperature, °R and/ or°F U = velocity, fps x = surface distance measured from cone apex, in. x t = surface distance location of boundary-layer transition, in. 3* = boundary-layer displacement thickness (tunnel wall), in. e c = cone half-angle, deg Presented as Paper 70-799 at
