Vortex-induced vibrations (VIV) and galloping effects are studied for the case of two cylinders in tandem arrangement. Both cylinders are allowed to move in X and Y directions and rigidity is kept the same for both directions. The cross-flow around moving cylinders is computed using a specifically designed numerical method which has been thoroughly verified and validated with manufactured solutions and systematic comparisons between numerical and available experimental results. It consists of a monolithic finite element method for solving fluid-structure problems. After validation results, we present configurations for a center-to-center distance L/D = 4 and reduced velocities ranging from 4 to 16 at a laminar Reynolds number of 200.
We study vortex-induced vibrations (VIV), interference and galloping phenomena occurring when two and three circular cylinders arranged in-line are placed in a uniform flow. If VIV for single circular cylinders are well documented, VIV, interference and galloping phenomena studies for arrays of cylinders remain sparse since Bokaian and Geoola (1984) and Zdravkovitch (1985). Recent experiments by Germain et al. (2006) showed that wake-induced vibrations occur for reduced velocities far beyond than 10. In Germain et al. (2006) peak displacements of the rear cylinder are much larger than one diameter transversely and it is also shown that in-line peak vibration amplitudes may be larger than one diameter. Available numerical studies on XYoscillating in-line cylinders in cross-flow depict results below reduced velocities of 7 [see Fregonesi et al. (2001); Mittal and Kumar (2001, 2004); Potanza et al. (2005)]. In Etienne (2008), we presented results till values of 10 of the reduced velocity. To shed light on wake-induced vibrations and reveal some of the features highlighted in the work by Germain et al. (2006), much larger reduced velocities shall be studied. In this work the range of studied reduced velocities is extended to values of 16.
