Title: Fluidelastic instabilities in tube bundles exposed to nonuniform crossflow
Abstract: A mathematical model is presented for fluidelastic instabilities in tube bundles exposed to nonuniform crossflow to develop an equivalent flow velocity. The model incorporates all motion-dependent fluid forces based on the unsteady flow theory. Published fluid-force coefficients are compiled and examined; all fluid-force coefficients are approximately independent of the reduced flow velocity when it is large but are strongly dependent on reduced flow velocity when it is lower. The unsteady flow model is used to show that the mode-weighted averaging method is valid for large reduced flow velocity, but that it is incorrect at lower reduced flow velocity. In the lower reduced flow velocity range, an iterative procedure is needed to establish the critical flow velocity. The results from the unsteady flow model are compared with those of other mathematical models. A general procedure is recommended to predict the equivalent flow velocity under different situations. 24 refs., 20 figs., 5 tabs.