Experimental study of air-water interface properties in self-aerated flows

The microscopic air-water structures and the interface area properties in the self-aerated flows are important research issues in the high-speed self-aerated flows. The present experimental study concerns the mean and medium air chord length distributions in the self-aerated chute flows for different flow Reynolds numbers and air concentration conditions. The relationship between the microscopic and the macroscopic aerated properties in the air-water mixture region is analyzed. The distribution of the microscopic specific air-water interface area with the macroscopic air concentration variation is self-similar in the self-aerated region. In view of the difference of the air-water structure in high and low aerated regions, a new relationship is proposed for predicting the distributions of a specific air-water interface area, and the agreement between the measured and predicted results is satisfactory.