Measurements of Temperature Field of Rayleigh-Bernard Convection by Using Two-Color Laser Induced Fluorescence

Abstract

Time-dependent instantaneous planar distribution of water temperature in a Rayleigh-Bernard convection was measured by using two-color laser induced fluorescence technique. Two fluorescent dyes, Rhodamine B and Rhodamine 110,were used as temperature indicators. A laser light sheet excited the fluorescent dyes, and an optical system involving a color beam splitter gave the intensity distribution of the individual fluorescent dyes on the two separate high-resolution monochrome CCD cameras. The ratio of these fluorescence intensities at each point of the image was calibrated against the temperature to eliminate the effect of the fluctuation of illuminating light intensity. It was visualized that the mushroom-like thermal plumes were generated from bottom and top surfaces.