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A computational fluid dynamics (CFD)-based aero-optics validation study was conducted at 1:1 scale in wind tunnel tests. Validation was based on fluid mechanical and optical measurements. A 12” diameter hemisphere-on-cylinder turret was tested in the US Air Force Academy 3 ft X 3 ft subsonic wind tunnel, at flow speeds ranging from Mach 0.3 to Mach 0.5. Flow validation was based on mean and rms velocity, mean pressure profile, rms unsteady pressure, and separation point. Optical validation was based on rms phase variance and in-flow phase correlation length derived from two-dimensional Hartmann wavefront sensor data, measured over a 5-inch beam diameter. The CFD code used a twoequation turbulence model with Partially-Averaged Navier-Stokes (PANS) approach. Measurement and prediction show generally good agreement over line-of-sight angles ranging from 60 to 132 degrees. Nomenclature CP = static pressure coefficient E{...} = expectation value F = spatial frequency M∞ = free stream Mach number p∞ = free stream pressure q = dynamic pressure 1 Engineer, Boeing-SVS, Albuquerque, NM, AIAA Member. 2 Technical Fellow, Boeing DES, West Hills, CA. 3 Engineer, Boeing DES, West Hills, CA. 4 Professor, University of Notre Dame Aerospace Dept, Notre Dame, IN, AIAA Fellow. 5 Research Assistant, University of Notre Dame Aerospace Dept, Notre Dame IN, AIAA Member. 6 Directed Energy Program Manager, Office of Naval Research, ONR 351, Washington DC. 7 Senior Research Physicist, Air Force Research Laboratory, AFRL/DE, Kirtland AFB, NM. 8 Director, Aeronautics Research Center, Department of Aeronautics, US AFA, Colorado Springs, CO, AIAA Associate Fellow. 38th AIAA Plasmadynamics and Lasers Conference In conjunction with the 16th 25 28 June 2007, Miami, FL AIAA 2007-4011 Copyright © 2007 by the American Institute of Aeronautics and Astronautics, Inc. The U.S. Government has a royalty-free license to exercise all rights under the copyright claimed herein for Governmental purposes. All other rights are reserved by the copyright owner. American Institute of Aeronautics and Astronautics 2 Rxx = autocorrelation function S = cross-spectrum U∞ = free stream velocity ρ∞ = free stream density φ = phase = time average |
