Pressure-Sensitive Paint system for measurements in a large low speed wind tunnel

Pressure-Sensitive Paint is an experimental technique that provides non-intrusive measurements of surface pressure with high spatial resolution. Pressure-Sensitive Paint systems have been deployed in several transonic wind tunnels as a standard instrument for production testing. Several successful tests in small low speed tunnels have also been demonstrated. These demonstrations generally require careful experimental procedures that are not practical in larger production tunnels. The Agency for Defense Development and Innovative Scientific Solutions have recently deployed a Binary Pressure-Sensitive Paint system in the 3-meter low speed tunnel in Taejon. This Binary Pressure-Sensitive Paint system uses a reference channel to compensate for errors that result from variations in temperature and illumination over the model surface. Experimental measurements on a model at speeds of 46, 60, and 80 meters per second were conducted and the results are presented here. The data from this first entry achieved an rms deviation of 150-Pa between the pressure paint and pressure taps. With minor modifications to the system, pressure paint measurements with an rms deviation of less than 100-Pa are expected in this low-speed wind tunnel.