<DOC>
<DOCNO>
338
</DOCNO>
<TITLE>
mass transfer cooling at mach number 4. 8.
</TITLE>
<AUTHOR>
leadon,b.m., scott,c.j. and anderson,g.e.
</AUTHOR>
<BIBLIO>
j. ae. scs. 25, 1958.
</BIBLIO>
<TEXT>
mass-transfer experiments on a 5 mil wire porous cone
of 20 total angle have been conducted at using
air and helium injection .  details of the experimental technique
are described in references 1 and 2 .  in the laminar boundary
layer the recovery factors and heat-transfer coefficients measured
with zero injection agreed within per cent with theory .
transition reynolds numbers observed on the porous cone with
zero injection were half as large as observed on a smooth, impermeable
model of identical geometry in the same channel, but
injection of large amounts of air or helium did not cause transition
to move forward from its zero-injection position on the
porous cone .  distributed roughness of this type apparently does
not disturb impermeable wall theory, but it masks whatever
effective roughness may be caused by discrete pore injection .
</TEXT>
</DOC>
