Measurement of temperature field of a Rayleigh-Bénard convection using two-color laser-induced fluorescence

The two-color laser-induced fluorescence technique developed by Sakakibara and Adrian (1999) for the measurement of planar turbulent temperature fields in water has been refined to reduce the RMS error of the instantaneous measurement by an order of magnitude. The technique achieves higher sensitivity by employing two high-resolution 14-bit monochrome CCD cameras. Further refinement is achieved by post-processing the data using a convolution method that matches the degree of the image blurring of the two images. The method is demonstrated by application to turbulent Rayleigh-Bénard convection wherein the random error is shown to be less than 0.17 K.