Accession Number : ADA563707


Title :   Yip - Development and Application of a High-Speed Three-Dimensional Density Measurement Technique for Aero-Optic Applications


Descriptive Note : Final rept. Apr 2008-Mar 2011


Corporate Author : AUBURN UNIV AL DEPT OF AEROSPACE ENGINEERING


Personal Author(s) : Thurow, Brian S


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a563707.pdf


Report Date : 25 Mar 2011


Pagination or Media Count : 96


Abstract : A density measurement technique based on the planar laser induced fluorescence (PLIF) of acetone vapor was developed and shown to be practical for 2-D density measurements in a high speed wind transonic wind tunnel. The random uncertainty in density measurements was estimated to be on the order of 8% without pixel binning and as low as 3% with pixel binning, thus showing that acetone PLIF is a viable technique for measurement of density in compressible flow fields. The technique was applied to visualize the shock induced separation and turbulent wake of a hemisphere mounted in a Mach 0.78 free stream. Density images clearly showed the presence of shock waves, a flapping wake structure and significant density drops within the cores of vortices formed in the separating free shear layer. The density drops could reach magnitudes up to 50% from the free stream value confirming that compressibility effects on density fluctuations within a weakly compressible shear layer are significant and cannot be explained through mixing models alone.


Descriptors :   *OPTICS , COMPRESSIBLE FLOW , DENSITY , FLOW FIELDS , IMAGES , LASER INDUCED FLUORESCENCE , TRANSONIC WIND TUNNELS , WAKE


Subject Categories : Optics


Distribution Statement : APPROVED FOR PUBLIC RELEASE