Experimental and theoretical study on natural circulation flow under rolling motion condition

The effect of rolling motion on the natural circulation flow was studied experimentally and theoretically. The experiment was divided two parts. One analyzed rolling and the other non-rolling motion. The experimental results show that the rolling motion yields periodically fluctuating fluid flow, and the period of fluctuation is the same as the rolling period. The amplitude of fluctuation increased with increasing roll amplitude and frequency, but the volume circulating decreased due to the rolling motion. A mathematic model was developed to calculate the natural circulation flow under rolling motion. The calculated results are in reasonable agreement with the experimental data. The results show that an increase in the coefficient of resistance to flow is the main factor affecting the decrease in natural circulation volume flow in the presence of rolling motion.