*Neal Tetervin*

*naca-tn-4350*

*Sep 1958*

The laminar-boundary-layer thickness, the boundary-layer Reynolds number and minimum critical Reynolds number, and the roughness Reynolds number have been calculated by an approximate method for a sphere and disk in the supercritical Reynolds number region. The calculations for the sphere show that the boundary-layer at the stagnation point of a sphere is much thicker than that on the airfoil, that the boundary-layer thickness increases very slowly with an increase in distance from the stagnation point, that the boundary-layer over the forward portion of a sphere is highly stable at large Reynolds numbers with respect to the Tollmien-Schlichting type of waves, and that roughness of a given height produces the largest roughness Reynolds numbers at about 57 degrees from the stagnation point.

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http://naca.central.cranfield.ac.uk/reports/1958/naca-tn-4350.pdf