Abstract: The optical rays that form the image of
an object and propagate a supersonic flow over a vehicle are
refracted by the density variations. A numerical analysis of the
aero-optical characteristics of supersonic flow over blunt wedge
with a cavity window is carried out. A hybrid method of Reynold
averaged Navier-Stokes and direct simulation Monte Carlo (RANS/DSMC)
is employed to simulate the flowfield. Refraction factor is
introduced to evaluate the flowfield's aero-optical characteristic.
The results show that mean flow's aero-optical effects are mainly
caused by the shock wave, the expansion wave and the turbulent
boundary layer. Fluctuation flow's aero-optical effects are mainly
caused by the turbulent boundary layer and the shock wave induced by
the cavity window. The aero-optical effects at the leading side of
window are caused by the mean density variations, while the effects
at the trailing side are caused by the density fluctuations.
Different draft angles of the cavity window are investigated. The
airborne optical devices of supersonic vehicle should be mounted in
the middle of the cavity window with a large draft angle.

Key words:

aero-optics| supersonic flow| blunted wedge|
cavity window

摘要： The optical rays that form the image of
an object and propagate a supersonic flow over a vehicle are
refracted by the density variations. A numerical analysis of the
aero-optical characteristics of supersonic flow over blunt wedge
with a cavity window is carried out. A hybrid method of Reynold
averaged Navier-Stokes and direct simulation Monte Carlo (RANS/DSMC)
is employed to simulate the flowfield. Refraction factor is
introduced to evaluate the flowfield's aero-optical characteristic.
The results show that mean flow's aero-optical effects are mainly
caused by the shock wave, the expansion wave and the turbulent
boundary layer. Fluctuation flow's aero-optical effects are mainly
caused by the turbulent boundary layer and the shock wave induced by
the cavity window. The aero-optical effects at the leading side of
window are caused by the mean density variations, while the effects
at the trailing side are caused by the density fluctuations.
Different draft angles of the cavity window are investigated. The
airborne optical devices of supersonic vehicle should be mounted in
the middle of the cavity window with a large draft angle.

关键词:

aero-optics| supersonic flow| blunted wedge|
cavity window