Surface coatings for optical pressure measurements

A relatively new technique that employs the tools of molecular spectroscopy to measure pressures optically is discussed. Measurements are made via pressure-sensitive molecules attached to the surface of interest. The measurement concept and data-acquisition as well as limitations of the technique are discussed. This paper is focused on identifying the research required to transform this concept into a robust measurement tool. Application goals include enhancement of current steady-state wind-tunnel capability by means of improving measurement accuracy and increasing the operational pressure range of the coatings. These developments will permit the measurement technique to be used in low-speed and high-Reynolds-number wind-tunnel applications. An improved operational range for the coatings will also accommodate studies in turbomachinery. In addition, a principal goal is improving the time response of the coatings to enable transient measurements