STRONGLY COUPLED FLUID-STRUCTURE INTERACTIONS VIA A NEW NAVIER-STOKES METHOD FOR PREDICTION OF VORTEX-INDUCED VIBRATIONS

摘要

Numerical prediction of vortex-induced vibrations requires employment of the unsteady Navier-Stokes equations. Current Navier-Stokes solvers are quite expensive for three-dimensional flow-structure applications. Acceptance of Computational Fluid Dynamics as a design tool for the offshore industry requires improvements to current CFD methods in order to address the following important issues: (ⅰ) stability and computation cost of the numerical simulation process, (ⅱ) restriction on the size of the allowable time-step due to the coupling of the flow and structure solution processes, (ⅲ) excessive number of computational elements for 3-D applications, and (ⅳ) accuracy and computational cost of turbulence models used for high Reynolds number flow. The above four problems are addressed via a new numerical method which employs strong coupling between the flow and the structure solutions. Special coupling is also employed between the Reynolds-averaged Navier-Stokes equations and the Spalart-Allmaras turbulence model. An element-type independent spatial discretization scheme is also presented which can handle general hybrid meshes consisting of hexahedra, prisms, pyramids, and tetrahedral.