Transonic Nozzle-Afterbody Flow Field Measurements Using a Laser Doppler Velocimeter,
CALSPAN FIELD SERVICES INC ARNOLD AFS TN AEDC DIV
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An investigation is described for providing detailed nonintrusive laser Doppler velocimeter LDV flow field measurements for several nozzle-afterbody configurations with cold nitrogen exhaust jets. Pertinent information about the test facility and associated instrumentation system is given. The test articles, including one with a 15 deg. boattail afterbody and two having blunt bases, are described. The two-color, two-component LDV optical package and data acquisition system used for the flow field measurements are discussed. The effects of particle dynamics upon the LDV measurement uncertainty are reviewed. Recent work directed toward predicting and correcting for such effects is explained. Fluorescent seeding was used in conjunction with multiple seeding techniques to gain a more complete understanding of the complex flow interactions in the model base region. Test results are summarized and selected data are presented and discussed.