Tube arrays exposed to air, gas or liquid cross-flow can vibrate due to vortex-shedding, turbulence, or fluidelastic instability. The major emphasis of this paper is on the phenomenon of fluidelastic instability (or fluidelastic vibration). A numerical model is applied to the simulation of fluidelastic vibration of representative tubes in a tube bundle, based on S. S. Chen’s unsteady flow theory. The results are validated against published data based on linear cases. The model is then applied to a nonlinear structure of a U-bend tube bundle with clearances at supports, and the computed results compared to those obtained by experimental testing. The numerical studies were performed using the ABAQUS-EPGEN finite element code using a special subroutine incorporating fluidelastic forces. It is shown that the results of both the linear and nonlinear modeling are in good agreement with experimental data.

An experimental study was conducted on the effect of tube-to-tube ties on the fluidelastic instability of an in-line tube array with a streamwise pitch ratio of 1.33 and a transverse pitch ratio of 2.0. Various arrangements of tubes clamped in the streamwise direction were examined. The results showed that clipping two tubes together had a stabilizing effect, but also exhibited substantial hysteresis. On the other hand, longitudinal clipping of three, four, or six tubes together increased the fluidelastic stability threshold by a factor of more than three. [S0094-9930(00)01501-8]

Tube-to-tube ties and their arrangement within the tube array are shown to affect the onset of fluidelastic instability. The influence of tie arrangement for a single tube row and for an in-line tube array is obtained by numerical simulation using S. S. Chen’s unsteady flow theory. Maps of dimensionless critical velocities for groups of tubes consisting of two, three, four, and five tubes tied to each other are developed for several design configurations. It is shown that the stability limits can be raised by appropriate choice of tube group and tie location.