Preliminary investigation of the delay of turbulent flow separation by means of wedge-shaped bodies Page: 3 of 31
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NACA RM A50L12
small low-aspect-ratio wings to mix high-energy air from the outer flow
with the low-energy air near the surface on which boundary-layer control
is desired. It was reasoned that a wedge-shaped body would combine both
flow mechanisms and have the additional advantage of discharging the
oncoming boundary layer flowing up the ramp as a sheet of vorticity over
the oblique edge of the wedge. The discharged sheet of vorticity would,
in turn, roll up into a trailing vortex. Thus, the action of the wedge
would be threefold, and was expected to exert a powerful control on
The investigation, conducted in the Ames 7- by 10-foot wind tunnels,
consisted of, first, an exploration of the flow associated with indi-
vidual wedges when mounted on a flat plate, and, second, a determination
of the effectiveness of multiple wedges for delaying separation of the
turbulent boundary layer from the upper surface of a two-dimensional
The coefficients and symbols contained in this report are defined
b wing span, feet
c wing chord, feet
cd average section drag coefficient, corrected for jet-boundary effect
by the method of reference 3 drg)
6cd incremental section drag coefficient [(cd for airfoil with
wedges) - (cd for airfoil without wedges)]
c1 average section lift coefficient, corrected for jet-boundary effect
by the method of reference 3 ( ft)cb
cm average section pitching-moment coefficient referred to the quarter
chord, corrected for jet-boundary effect by the method of refer-
ence 3 pitching moment
LH local total-pressure decrement [ (free-stream total pressure) -
(local total pressure in boundary layer or trailing vortex)],
pounds per square foot
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McCullough, George B.; Nitzberg, Gerald E. & Kelly, John A. Preliminary investigation of the delay of turbulent flow separation by means of wedge-shaped bodies, report, March 1, 1951; (digital.library.unt.edu/ark:/67531/metadc58702/m1/3/: accessed January 19, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.