Pressure Sensitive Paint Studies of Vortical Flow at Low Speed

To demonstrate the capability of the pressure sensitive paint technique in a low-speed environment, a series of tests have been conducted in the NASA-Langley Basic Aerodynamics Research Tunnel to obtain detailed pressure measurements on geometries that generate strong vortical flow fields. Four configurations with highly swept leading edges were used. All models were instrumented with pressure ports to provide an in situ calibration and comparison with the pressure sensitive paint. Results from these tests showed good agreement between the paint and port pressure measurements. In order to achieve this good agreement, special considerations must be given to pressure-sensitive-paint tests at low speed. This paper discusses the practical considerations for applying this technique in a low-speed wind tunnel environment.