Three-dimensional computation for flow-induced vibrations of two circular cylinders in tandem arrangement with narrow spacing

Abstract

Flow-induced vibrations of two circular cylinders in tandem arrangement which are mounted in a three-dimensional flow field are investigated at a high Reynolds number of 20,000. A third-order upwind finite element scheme and the arbitrary Lagrangian–Eulerian (ALE) formulation are used to solve the three-dimensional incompressible Navier–Stokes equations. Two circular cylinders which are treated as rigid bodies are free to vibrate in both in-line and cross-flow directions. Accordingly, both cylinders are assumed as a two-degree of freedom system. The upstream cylinder is set in a smooth flow and the downstream cylinder lies in the wakes which are shed from the upstream one. Spacing S between center-to-center of the cylinders is 2D and 3D (D is the diameter of the cylinders ) less than the critical spacing. The Scruton number Sc with respect to the flow-induced vibration is given as 0.99. The excitation vibrations to the in-line direction occur in the low range of the reduced velocity because of the low Scruton number. In addition, large cross-flow amplitudes of both cylinders are observed in the high range of the reduced velocity.