We report the first use of the resonant Doppler velocimeter (RDV) for complete flow field visualization in a supersonic airflow. The RDV is a new nonintrusive diagnostic tool which takes advantage of laser absorption effects to measure the velocity, temperature, and pressure of a flowing gas. In this manner it eliminates particle lag, which is characteristic of standard laser Doppier velocimetry. Tracer atoms or molecules are seeded into the flowing gas under investigation and are excited by an intersecting laser beam. Since the gas is moving, the absorption frequency is Doppler shifted. This technique may be used for flow visualization. An expanded narrow linewidth laser beam may be tuned so that regions in the flow with a specific velocity component fluoresce brightly enough to be seen with the naked eye.
© 1982 Optical Society of AmericaPDF Article