Simultaneous planar measurements of velocity and pressure fields in gas flows using laser-induced fluorescence.

The development of a nonintrusive spectroscopic technique is reported which permits simultaneous spatially resolved measurements of two velocity components and pressure in a plane of a compressible gaseous flow field. The technique is based on the detection of fluorescence from an absorption line excited with a narrowbandwidth laser. Doppler shift and pressure broadening of the line are exploited to extract velocity and pressure information, respectively. The fluorescence is detected at a 90 degrees angle with an image-intensified 100 x 100 element photodiode-array camera which is interfaced with a laboratory computer. Results of the implementation in a Mach 1.5 underexpanded supersonic jet are presented.