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Computational study of optical distortions by separated shear layers and turbulent wakes

  • ALI MANI (a1), PARVIZ MOIN (a1) and MENG WANG (a2)
Abstract

The flow over a circular cylinder at ReD = 3900 and 10000 and M = 0.4 is considered a platform to study the aero-optical distortions by separated shear layers and turbulent wakes. The flow solution is obtained by large eddy simulation (LES) and validated against previous experimental and numerical results. The fluctuating refractive index obtained from LES is used in a ray-tracing calculation to determine wavefront distortions after the beam passes through the turbulent region. Free-space propagation to the far field is computed using Fourier optics. The optical statistics are analysed for different conditions in terms of optical wavelength, aperture size and the beam position. It is found that there exists an optimal wavelength which maximizes the far-field peak intensity. Optical results at both Reynolds numbers are compared. The optical distortion by the downstream turbulent wake is found to be Reynolds number insensitive. However, due to their different transition mechanisms, distortions by the near wake regions are different in the two flows. The aero-optical effects of different flow scales are examined using filtering and grid refinement. Through a grid convergence study it is confirmed that an adequately resolved LES can capture the aero-optics of highly aberrating flows without requiring additional subgrid scale model for the optics.

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Corresponding author
Email address for correspondence: alimani@stanford.edu
References
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Beaudan P. & Moin P. 1994 Numerical experiments on the flow past a circular cylinder at sub-critical Reynolds number. Tech Rep. TF-62. Department of Mechanical Engineering, Stanford University.
Cassady P. E., Birch S. F. & Terry P. J. 1989 Aero-optical analysis of compressible flow over an open cavity. AIAA J. 758–762.
Catrakis H. J. & Aguirre R. C. 2004 New interfacial fluid thickness approach in aero-optics with applications to compressible turbulence. AIAA J. 42, 19731981.
Catrakis H. J., Aguirre R. C., Ruiz-plancarte J., Thayne R. D., McDonald B. A. & Hearn J. W. 2002 Large-scale dynamics in turbulent mixing and the three-dimensional space–time behavior of outer fluid interfaces. J. Fluid Mech. 471, 381408.
Childs R. E. 1993 Prediction and control of turbulent aero-optical distortion using large eddy simulation. Paper 93-2670. AIAA.
Dimotakis P. E., Catrakis H. J. & Fourguette D. C. 2001 Flow structure and optical beam propagation in high-Reynolds number gas-phase shear layer and jets. J. Fluid Mech. 433, 105134.
Dong S., Karniadakis G. E., Ekmekci A. & Rockwell D. 2006 A combined direct numerical simulation–particle image velocimetry study of the turbulent near wake. J. Fluid Mech. 569, 185207.
Freeman A. P. & Catrakis H. J. 2008 Direct reduction of aero-optical aberrations by large structure suppression control in turbulence. AIAA J. 46, 25822590.
Gilbert K. G. 1982 Overview of aero-optics. (ed. Gilbert K. and Otten L. J.) In Progress in Astronautics and Aeronautics: Aero-Optical Phenomena, American Institute of Aeronautics and Astronautics, New York, N.Y. vol. 80, pp. 19.
Gordeyev S., Jumper E. J., Ng T. T. & Cain A. B. 2003 Aero-optical characteristics of compressible, subsonic turbulent boundary layers. Paper 2003-3606. AIAA.
Ho C. M. & Huerre P. 1984 Perturbed free shear layers. Annu. Rev. Fluid Mech. 16, 365424.
Hugo R. J., Jumper E. J., Havener G. & Stepanek C. 1997 Time-resolved wave front measurements through a compressible free shear layer. AIAA J. 35, 671677.
Jones M. I. & Bender E. E. 2001 CFD-based computer simulation of optical turbulence through aircraft flowfields and wakes. Paper 2001-2798. AIAA.
Kravchenko A. G. & Moin P. 1998 B-spline methods and zonal grids for numerical simulations of turbulent flows. Tech Rep. TF-73. Department of Mechanical Engineering, Stanford University.
Kravchenko A. G. & Moin P. 2000 Numerical studies of flow over a circular cylinder at Re D = 3900. Phys. Fluids 12, 403417.
Lilly D. K. 1992 A proposed modification of the Germano subgrid-scale closure method. Phys. Fluids A 4, 633635.
Mahajan V. N. 1983 Strehl ratio for aberration in terms of their aberration variance. J. Opt. Soc. Am. 73, 860861.
Malley M., Sutton G. W. & Kincheloe N. 1992 Beam-jitter measurements of turbulent aero-optical path differences. Appl. Opt. 31, 44404443.
Mani A., Wang M. & Moin P. 2006 Statistical description of free-space propagation for highly aberrated optical beams. J. Opt. Soc. Am. A 23, 30273035.
Mani A., Wang M. & Moin P. 2008 Resolution requirements for aero-optical simulations. J. Comput. Phys. 227, 90089020.
Mittal R. & Moin P. 1997 Suitability of upwind-biased finite-difference schemes for large-eddy simulation of turbulent flows. AIAA J. 35, 14151417.
Moin P., Squires K., Cabot W. & Lee S. 1991 A dynamic subgrid-scale model for compressible turbulence and scalar transport. Phys. Fluids A 3, 27462757.
Nagarajan S., Lele S. K. & Ferziger J. H. 2003 A robust high-order compact method for large eddy simulation. J. Comput. Phys. 191, 392419.
Ong L. & Wallace J. 1999 The velocity field of the turbulent very near wake of a circular cylinder. Exp. Fluids 20, 441453.
Press W. H., Teukolsky S. A., Vetterling W. T. & Flannery B. P. 2007 Numerical Recipes: The Art of Scientific Computing. Cambridge University Press.
Rizzetta D. P., Visbal M. R. & Blaisdell G. A. 2003 A time-implicit high-order compact differencing and filtering scheme for large-eddy simulation. Intl J. Numer. Methods Fluids 42, 665693.
Saleh B. E. A. & Teich M. C. 1991 Fundamentals of Photonics. John Wiley & sons.
Sinha N., Arunajatesan S., Seiner J. M. & Ukeiley L. S. 2004 Large-eddy simulations of aero-optic flow fields and control application. Paper 2004-2448. AIAA.
Smith R. & Truman C. 1990 Prediction of optical phase degradation using a turbulent transport equation for the variance of index-of-refraction fluctuations. Paper 90-0250. AIAA.
Sutton G. W. 1969 Effect of turbulence fluctuations in an optically active fluid medium. AIAA J. 7, 17371743.
Sutton G. W. 1985 Aero-optical foundations and applications. AIAA J. 23, 15251537.
Tromeur E., Garnier E. & Sagaut P. 2006 Large eddy simulations of aero-optical effects in a spatially developing turbulent boundary layer. J. Turbul. 7 (001).
Tromeur E., Garnier E., Sagaut P. & Basdevant C. 2003 Large eddy simulations of aero-optical effects in a turbulent boundary layer. J. Turbul. 4 (005).
Truman C. R. 1992 The influence of turbulent structure on optical phase distortion through turbulent shear flows. Paper 92-2817. AIAA.
Truman C. R. & Lee M. J. 1990 Effects of organized turbulence structures on the phase distortion in a coherent optical beam propagating through a turbulent shear flow. Phys. Fluids A 2, 851857.
Tsai Y. P. & Christiansen W. H. 1990 Two-dimensional numerical simulation of shear-layer optics. AIAA J. 28, 20922097.
Visbal M. R. & Rizzetta D. P. 2008 Effect of flow excitation on aero-optical aberration. Paper 2008-1074. AIAA.
Wolfe W. L. & Zizzis G. J. 1978 The Infrared Handbook. Office of Naval Research, Department of the Navy.
Zdravkovich M. M. 1997 Flow around Circular Cylinders. Oxford University Press.
Zeldovich B. Y., Mamaev A. V. & Shkunov V. V. 1995 Speckle-wave Interactions in Application to Holography and Nonlinear Optics. CRC Press.
Zubair F. R. & Catrakis H. J. 2007 Aero-optical resolution robustness in turbulent separated shear layers at large Reynolds numbers. AIAA J. 45, 27212728.
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