The high-enthalpy, hypersonic flow over a compression corner has
been examined
experimentally and theoretically. Surface static pressure and heat
transfer distributions, along with some flow visualization data, were obtained
in a free-piston shock
tunnel operating at enthalpies ranging from 3 MJ kg−1 to
19 MJ kg−1, with the Mach
number varying from 7.5 to 9.0 and the Reynolds number based on upstream fetch
from 2.7×104 to 2.7×105. The flow was
laminar throughout. The experimental data
compared well with theories valid for perfect gas flow and with other relevant
low-to-moderate enthalpy data, suggesting that for the current experimental
conditions,
the real gas effects on shock wave/boundary layer interaction are
negligible. The
flat-plate similarity theory has been extended to include equilibrium
real gas effects.
While this theory is not applicable to the current experimental conditions,
it has been
employed here to determine the potential maximum effect of real gas behaviour. For
the flat plate, only small differences between perfect gas and equilibrium gas flows
are predicted, consistent with experimental observations. For the compression corner,
a more rapid rise to the maximum pressure and heat transfer on the ramp face is
predicted in the real gas flows, with the pressure lying slightly
below, and the heat
transfer slightly above, the perfect gas prediction. The increase in
peak heat transfer
is attributed to the reduction in boundary layer displacement thickness due to real
gas effects.