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.
LI Bo (李 波), LIU Hong (刘 洪)
. Aero-Optical Characteristics of Supersonic Flow over Blunt Wedge
with Cavity Window[J]. Journal of Shanghai Jiaotong University(Science), 2011
, 16(6)
: 742
-749
.
DOI: 10.1007/s12204-011-1219-z
[1] Tromeur E, Garnier E, Sagaut P. Large-eddy simulation of aero-optical effects in spatially developing turbulent boundary layer [J]. Journal of Turbulence, 2006, 7 (1): 1-28.
[2] Sutton G W. Aero-optical foundations and applications [J]. AIAA Journal, 1985, 23 (10): 1525-1537.
[3] Wyckham C, Zaidi S H, Miles R B, et al. Measurement of aero-optic distortion in transonic and hypersonic, turbulent boundary layers with gas injection [C]// AIAA Plasmadynamics and Lasers Conference. Toronto, Canada: AIAA, 2005: 1500-1529.
[4] Fitzgerald E J, Cicchiello J M, Siegenthaler J P, et al. Optical characterization of the notre dame compressible shear-layer facility [C]// AIAA Plasmadynamics and Lasers Conference. Maui, USA: AIAA, 2002: 1600-1629.
[5] Gordeyev S, Jumper E J, Ng T T, et al. Aero-optical characteristics of compressible, subsonic turbulent boundary layers [C]// AIAA Plasmadynamics and Lasers Conference. Orlando, USA: AIAA, 2003: 1400-1429.
[6] Hugo R J, Jumper E J, Havener G, et al. Time-resolved wave front measurements through a compressible free shear layer [J]. AIAA Journal, 1997, 35 (4): 671-677.
[7] Wu Qi-fen, Chen Wei-fang, Huang Lin, et al. Rarefied gas dynamics [M]. Changsha, China: Defense Science University Press, 2004 (in Chinese).
[8] Augirre R C, Catrakis H. J. Aero-optical wavefronts and scale-local characterization in large-Reynolds-number compressible turbulence [J]. AIAA Journal, 2004, 42 (10): 1982-1990.
[9] Balakumar P. Stability of supersonic boundary layers over blunt wedges [C]// AIAA Plasmadynamics and Lasers Conference. San Francisco, USA: AIAA , 2006: 1400-1419.
