Experimental Investigation of Thick, Axially Symmetric Boundary Layers on Cylinders at Subsonic and Hypersonic Speeds

An experimental investigation of the transverse curvature effect on laminar and turbulent axially symmetric boundary layers was conducted in two subsonic wind tunnels and in the GALCIT 5 x 5 inch hyper sonic wind tunnel. Subsonic turbulent skin friction coefficients were estimated from velocity profiles with axial flow on a 0.024 inch diameter cylinder and a 1.00 inch diameter cylinder. A considerable increase over the flat plate skin friction coefficient at the same momentum thickness Reynolds number was found. Hypersonic laminar and turbulent skin friction coefficients with axial flow on an insulated 0.250 inch diameter cylinder were measured by the floating element technique and indicated, respectively, several times, and 1.5 times the laminar and turbulent flat plate skin friction coefficients at the same momentum thickness Reynolds numbers. Turbulent skin friction coefficients were estimated from pi tot profiles with axial flow on a 0.064 inch diameter cylinder and on a 0.024 inch diameter cylinder at M_1 = 5. 8 and indicate double the value to be found for an insulated flat plate at the same momentum thickness Reynolds number.