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.
The structure of large-scale hypersonic boundary layer separation and reattachment is studied numerically using a flat plate/compression corner geometry. Apart from verifying the large scale separation characteristics in hypersonic flow, a detailed discussion of secondary separation and fragmentation into multiple vortices embedded within the main recirculation region is presented. The unique relation between the second minimum in shear stress and the scaled angle is highlighted in the context of the reverse flow singularity of Smith (Proc. R. Soc. Lond. A, vol. A420, 1988, pp. 21–52) and it appears that for a small wall temperature ratio, such a singularity is unlikely. It is shown that the size of the separation can be estimated in terms of Burggraf’s expression based on asymptotic theory.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.