<DOC>
<DOCNO>
625
</DOCNO>
<TITLE>
viscous and inviscid nonequilibrium gas flows .
</TITLE>
<AUTHOR>
whalen,r.j.
</AUTHOR>
<BIBLIO>
j. ae. scs. 29, 1962, 1222.
</BIBLIO>
<TEXT>
  the condition of immediate freezing of the mass fraction of
dissociated species of air at the equilibrium value behind the
shock envelope prevails over a major portion of the flight spectrum
associated with lifting re-entry vehicles .  this is observed
by means of order-of-magnitude considerations within the limits
of the present knowledge of chemical reaction rates for the constituents
of air .  accordingly, investigations of the viscous and
inviscid hypersonic flow about blunt and sharp leading edge
slender bodies are made .  the investigations are generalized to
consider an arbitrary degree of dissociation in the ambient free
stream .  this condition is included in order to allow comparison
with the flow field about a model in the test section of a hypersonic
facility with dissociated air species present in the free
stream .
  inviscid frozen flow investigations are made for blunt and
sharp leading edge slender body power-law geometries .  the
results indicate that the influence of a finite leading edge, in
inducing a pressure field far downstream (/blast-wave/ analogy),
is considerably diminished for this model .  this conclusion is
verified numerically by a characteristics solution for the hypersonic
flow about a /sonic-wedge/ slab .
  the viscous investigations consider the boundary-layer
interaction problem with a frozen degree of dissociation .  in
this case, as in the inviscid analysis, the governing parameter is
observed to be the ratio of the dissociation
energy to the free-stream kinetic energy .  the influence
of this parameter on the boundary-layer interaction
mechanism for a highly cooled, noncatalytic wall is presented .
the influence of a frozen flow field on skin friction and heat
transfer is also discussed .
  finally, since higher mach number gas flows may be generated
in wind tunnel nozzles where dissociation nonequilibrium effects
are present, the possibility of employing expansions with a
controlled degree of dissociation as a technique for aerodynamic
simulation is presented .
</TEXT>
</DOC>
