Density Measurements of a High-Speed, Compressible Flow Field Using Acetone Planar Laser Induced Fluorescence (PLIF)

Progress in the development of a density measurement technique using acetone planar laser induced uorescence (PLIF) is presented. PLIF data has been acquired in the separated shear layer and wake downstream of a wall-mounted hemisphere at transonic conditions (M1 0:78, ReD 9 10). An established acetone uorescence signal model was slightly modi ed and implemented to convert the raw images to density eld data. The uncertainty of the density measurement was determined to be approximately 8% due to uncertainty in local pressure and measurement noise. The density eld is marked by large scale structures and distinct vortex cores in the shear layer and wake region where density drops of up to 50% of the freestream density were observed. In addition, images of the shear layer reveal the formation of shock waves and lambda shocks at or near the separation point. This density data is used to calculate the aero-optical distortion for a planar wavefront passing through the ow eld. These results indicate that acetone PLIF is a viable technique for measuring density elds and studying aero-optical distortion in high-speed, compressible ows.