• Version
• 181 Downloads
• 1.49 MB File Size
• 1 File Count
• November 2, 2016 Create Date
• November 2, 2016 Last Updated

National Advisory Committee for Aeronautics, Report - An Investigation of the Effects of Heat Transfer on Boundary Layer Transition on a Parabolic Body of Revolution (NACA RM-10) At a Mach Number of 1.61

An investigation has been made of the ejects of heat transfer
on boundary-layer transition on a parabolic body of revolution
(NAO'A RM—10 without jins) at a Mach number of 1.61 and
overaReynolds number range from 2.6 X 10°to35 X 10“. The
maximum cooling of the model used in these tests corresponded
to a temperature ratio (ratio of model-surface temperature to
free—stream temperature) of 1.12, a value somewhat higher than
the theoretical value required for infinite boundary-layer sta-
bility at this Mach number. The maaimum heating corre-
sponded to a temperature ratio of about 1.85. Included in the
investigation was a studyof the ejects of surface irregzdarities
and disturbances generated in the airstream on the ability of
heat transfer to influence boundary-layer transition.

The results indicated that cooling the model increased the
Reynolds number for which laminar flow could be maintained
over the entire length of the body, whereas heating the model
decreased this transition Reynolds number. The trend of the
experimental results is in good agreement with that predicted
by boundary-layer stability calculations. The highest transi-
tion Reynolds number obtained with cooling was 28.5 X 10“.
At this Reynolds number the classical Tollmien-Schlichting
wave type of boundary-layer instability was apparently over-
shadowed by surface roughness ejects. Heating the model so
that the ratio of model-surface temperature to free—stream tem-
perature was 1.85 decreased the transition Reynolds number to
about 3 X 10“. The effects of heat transfer on transition were
considerably larger than previously found in similar investiga-
tions. It appears that, if the boundary-layer transition Rey-
nost number for zero heat transfer is large, then the sensitivity
of transition to heating or cooling is high; if the zero-heat-
transfer transition Reynolds number is low, then transition
is relatively insensitive to heat-transfer ejects. The results
also indicated that, when transition was fixed by surface irregu-
larities or airstream disturbances, cooling was not efective in
obtaining laminar flow behind the irregzdarity or disturbance.