Simulation of Flow Induced Vibrations of Tube Bundle in Cross Flow

Abstract

The flow-induced vibration of tubes in a rotated triangular array subject to cross flow is simulated numerically. In the study, the flow field around the tube bundle is computed by solving the continuity and Navier-Stokes equations with assumption of constant fluid properties, and the kε-model for turbulent Reynolds stress. With the flow field known, the fluid forces on the tube surfaces can be calculated, and then the displacement of each tube due to the fluid force can be evaluated. Iteration is needed to obtain the dynamic response of the tube structure in the fluid flow. The parameters in the study are inlet velocity of the cross flow and properties of the tube bundle including natural frequency, damping factor, and mass. Based on the tube response, the critical flow conditions of tube vibration are determined for varying mass damping. Once tube vibrations occur, it is shown that the vibrations of the tubes in the second and fourth tube rows are significant as compared to other tubes. The orbits of the tube vibration look like an ellipse with major axis in the cross-stream direction, implying large lift force on the tubes. The dominant frequency in the spectrum of lift coefficients of the tubes is the same as the natural frequency, and the corresponding amplitude is increased with increasing the inlet velocity. The calculated data predicted for the critical reduced velocity agrees well with the data by Kassera and Strohmeier [17].

A numerical study on fluid elastic vibrations of multiple cylinders in cross flow

“…These orbits were obtained by recording the displacement-time traces of the cylinder in the drag and lift directions for about ten cycles in final oscillation state. The experimental data of Lin (2002) are also shown in Figs. 10(d)-(f) for comparison.…”