Experiment of Chaotic Vibration of Loosely Supported Tube Rows in Cross-Flow

A tube array supported by baffle plates in cross-flow may be subjected to fluidelastic instability in the tube-support-plate-inactive mode. An experimental study is presented to characterize the tube motion. Three series of tests were performed to measure tube displacements as a function of flow velocity for differing clearances. The motion was examined by root-mean-square values of tube displacements, power spectral densities, phase planes, Poincare´ maps, and Lyapunov exponents. The experimental data agree reasonably well with an analytical model based on the unsteady flow theory.