3-DIMENSIONAL RAINBOW SCHLIEREN TOMOGRAPHY OF A TEMPERATURE-FIELD IN GAS-FLOWS

We present quantitative rainbow schlieren deflectometry with tomograph y for measurements of temperature in three-dimensional gas flows. The schlieren apparatus with a continuously graded spectral filter of know n transmissivity was used to create color schlieren images of the test media. These images at multiple viewing angles were used to infer bea m deflection angles by the medium. The deflection data were used with a tomographic technique to reconstruct the refractive index and thus t he temperature field. The temperature distributions obtained by the ra inbow schlieren tomography agreed with those measured by a thermocoupl e probe. This research demonstrates that tomography can be used with f ull-field schlieren deflectometry to measure quantitatively temperatur e in asymmetric gas flows. The technique could be used to obtain relat ed properties such as pressure, density, and gas composition. (C) 1998 Optical Society of America.