Interactive numerical simulation of riser interference phenomena in offshore structure

An integrated simulation environment for unsteady flow and flow-structure interaction problems has been developed for two-dimensional incompressible flows. The motivating problem, interference effects between flexible risers in offshore structures, presents a significant challenge to numerical simulation due to the heavy dependence on structural and flow parameters, the large-scale deformation possible in the risers, and the need to accurately visualize time-dependent phenomena.; To meet these challenges in the most efficient manner, an interactive simulation environment is developed which consists of a semi-implicit projection solver for the incompressible Navier-Stokes equations, automatic routines for mesh deformation and adaptation, algorithms for visualization of unsteady vector fields on arbitrary mesh topologies and interpolants, and flexible, cross-platform interactive steering processes. In each of these areas, a combination of established and novel techniques are used to provide efficiency and accuracy.; Results presented include extensive validation on standard benchmark problems and both unsteady flow and flow-structure interaction simulations for isolated cylinders and cylinder pairs. These results indicate that the developed methods provide an extremely powerful means to explore complex, unsteady simulations of relevance to offshore design.