An unsteady model for fluidelastic instability in an array of flexible tubes in two-phase cross-flow

The streamtube model for fluidelastic instability in single-phase flow was extended to two-phase flow by two kinds of two-phase flow model. One was the traditional HEM, and the other was the slip ratio model. The model based on slip ratio can represent the effect of velocity difference between gas and liquid phases, and was verified with the experimental data from the literature. Comparing to the conventional HEM model, the slip ratio model and the introduction of interfacial velocity could collapse the stability data from various studies, which is beneficial for predicting the fluidelastic instability of tube bundles from existing stability maps and methods.