Abstract
Non-linear dynamic behavior of two-phase natural circulation flow instability under rolling motion condition was studied with non-linear time series analysis methods. Under certain conditions, natural circulation system under the rolling motion will turn out irregular complex flow oscillations whose periodic characteristic is not obvious. In this work, the dynamic behavior of the natural circulation flow instabilities under rolling motion was satisfactorily quantified with respect to its geometric characteristics. The correlation dimension, K_2 entropy and maximal Lyapunov exponent of the irregular complex flow oscillations, density wave oscillation and trough-type flow oscillation, which is used to estimate the orbital instability in the attractor, was used to obtain more dynamic information on the natural circulation instability. The results indicated that rolling motion strengthened the nonlinear characteristics of two phase flow instability; and the chaotic characteristic of irregular complex flow oscillations is more obvious than density wave oscillation and trough-type flow oscillation.
