The turbulent vortex shedding arising from the cross flow past a circular cylinder is analyzed using a Large Eddy Simulation (LES) procedure. In particular, no explicit sub-grid stress model is employed. Rather, the unresolved scales are dealt implicitly by a stabilized Petrov-Galerkin finite element formulation used in conjunction with a time-space adaptive scheme. The numerical results are compared with available experimental data on force coefficients and vortex shedding frequency.
Vortex induced vibration is a major concern in Offshore Engineering. The flow around marine structures causes vibrations that may lead to failure by fatigue. The problem is of particular importance in deep water oil exploitation systems, where risers and mooring lines can be viewed as flexible slender cylinders subjected to cross flow. Moreover, for deep water systems the variation of water currents from the ocean surface to the seabed may be large. There is some controversy among researchers on what is the most appropriate way to tackle the problem (Franciss, 1999). We think that the development of Computational Fluid Dynamics (CFD) will have an increasingly important role in the analysis of the vortex-induced vibrations of these slender structures subjected to depthvarying currents. Although the coupled transient three-dimensional simulation of flow and structure needed to address the problem directly is still a colossal task, the time is ripe for paving the way towards such an ambitious goal. In this paper we tackle the more basic, but challenging problem, of simulating the turbulent vortex shedding around a stationary cylinder at the high Reynolds numbers typical of Offshore Engineering applications. A Large Eddy Simulation (LES) procedure is used to study the turbulent flow around a circular cylinder.
