[Thesis]. Manchester, UK: The University of Manchester; 2011.
Vortex shedding is an important mechanism, by which the flow around bluff bodies create
forces that excite vibratory motion. Vortex-induced vibration (VIV) is studied for
a single circular cylinder by means of Computational Fluid Dynamics (CFD) simulations.
An arbitrary Lagrangian Eulerian (ALE) formulation is used to achieve the grid deformation
needed for VIV. In this thesis, a multifaceted approach is undertaken by which response
dynamics and wake interaction are addressed. Four major aspects are considered in
the study: the Reynolds number (Re); the mass and damping; the degree-of-freedom for
VIV; and the mutual effect between VIV and heat transfer.As attention is paid towards
high pre-critical Re flow, the turbulent flow around the cylinder is treated by two
turbulence modelling approaches: unsteady Reynolds Averaged Navier Stokes (uRANS),
and Large Eddy Simulation (LES). The wake-VIV interaction is analyzed by looking at
mean velocities and Reynolds stresses, where decomposition of flow scales is undertaken
to explore the evolution of coherent eddy structures, downstream of the cylinder.
Conversely, the VIV response is analyzed by considering oscillation amplitude and
frequency, in addition to the excitation and inertial dynamics.High turbulence in
the separated shear layers disorders the cylinder's VIV response and induces higher
amplitudes. The sensitivity for Re is found more pronounced in cylinders with low
mass and damping. Meanwhile, VIV is found to enhance wake mixing, and to significantly
change the near wake Reynolds stresses. It is suggested that the increase in Re brings
a change to the wake patterns, which are known in VIV at lower Re. The kinetic energy
production, of near wake eddy structures, is qualitatively altered with the presence
of VIV. Furthermore, the surface heat flux is found to cause a noticeable increase
in VIV amplitude, as long as it does not disorder the wake correlation. The cylinder's
oscillation increases the average value of the Nusselt number (Nu), while the local
variance of Nu rises markedly post-separation.