Application of a high-speed laser-induced fluorescence technique for studying the three-dimensional structure of annular gas-liquid flow.

The wavy structure of liquid film in annular gas-liquid flow was studied using a high-speed modification of the laser-induced fluorescence (LIF) technique, which was adapted for three-dimensional measurements. The three-dimensional structure of different types of waves in regimes with and without liquid entrainment was investigated. A comparison of the circumferential size of different types of waves was performed. Disturbance waves at high liquid Reynolds numbers were shown to be circumferentially non-uniform, and it was shown that this non-uniformity affects the generation of ripples. [ABSTRACT FROM AUTHOR]