<DOC>
<DOCNO>
946
</DOCNO>
<TITLE>
exploratory investigation of the effect of a forward
facing jet on the bow shock of a blunt body in a mach
number 6 free stream .
</TITLE>
<AUTHOR>
romeo,d.j. and sterrett,j.r.
</AUTHOR>
<BIBLIO>
nasa tn.d1605, 1963.
</BIBLIO>
<TEXT>
  the effect of a forward-facing jet on
the bow shock of a blunt body in a
mach 6 free stream was investigated
experimentally .  the models tested had forwardfacing
jets using air and helium exhausting
at mach numbers from 1 to 10.3 and
were run through a range of the ratio of jet
total pressure to free-stream total
pressure of 0.03 (jet off) to 2.5 .  the ratio
of body diameter to jet-exit diameter
varied from 1.12 to 55.6 and the angle
of attack was varied from 0 to 35 .
  the experimental results show that the
main-stream shock can be affected by
the jet in two significantly different ways .
one way is simply to move the strong
shock away from the body without altering its
shape .  the second and perhaps more
interesting case occurs when the jet causes a
large displacement of the main shock
and considerably changes its shape .  it was
found that the ratio of jet total
pressure to free-stream total pressure necessary
to obtain the large displacements
of the main-stream shock depended on the ratio
of body diameter to jet-exit diameter
and also on the jet-exit mach number .  the
maximum amount the shock could be
displaced in percent of body diameter was seen
to increase with increasing jetexit
mach number and also with decreasing ratio
of body diameter to jet-exit diameter
.  for the models that were investigated
through an angle-of-attack range, the
displacement became very unsteady and fell off
sharply as the angle of attack was
increased .
  simplified theoretical considerations applied
to the shock-displacement
phenomena provide a possible explanation for the
two different types of mainstream
shock displacement .  theoretical curves
show the regions where these types
of displacement would occur for different exit
mach numbers and pressure ratios
for a forward-facing jet in a mach 6 stream .
</TEXT>
</DOC>
