Flow visualization in supersonic air with the resonant Doppler velocimeter

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