<DOC>
<DOCNO>
560
</DOCNO>
<TITLE>
a theoretical study of the effect of upstream transpiration-cooling
on the heat transfer and skin friction characteristics
of a compressible laminar boundary layer .
</TITLE>
<AUTHOR>
rubesin,m.w. and inouye,m.
</AUTHOR>
<BIBLIO>
naca tn.3969, 1957.
</BIBLIO>
<TEXT>
  an analysis is presented which predicts
the skin-friction and heattransfer
characteristics of a compressible,
laminar boundary layer on a
solid flat plate preceded by a porous
section that is transpiration cooled .
the analysis is restricted to a prandtl
number of unity and linear
variation of viscosity with temperature .
  the local skin friction has been
found to have a low value in the
region of transpiration cooling and then
to increase until it approaches
the value for a completely nonporous surface
asymptotically .  the initial
increase in local skin friction is rapid
as half of the ultimate increase
occurs in a distance beyond the porous
region that is about 20 percent of
the length of the porous region for all rates
of injection .  when the
total coolant flow rate is kept constant
and the porous length is varied,
it is found that the average skin friction
on a partially porous plate is
slightly lower than that on a fully porous plate .
  the local heat transfer behaves in
a manner similar to that of the
local skin friction .  it is found, in
an example, that the temperature
at the end of a partially porous plate
could be maintained at about the
same temperature as a fully porous plate
by doubling the total rate of
coolant flow .
</TEXT>
</DOC>
