Numerical Analysis of Vortex-Induced Yaw Motion of a Paired-Column Semi-Submersible in Currents
11th International Workshop on Ship and Marine Hydrodynamics (IWSH2019), Paper 70
Contribution to Conference
Vortex-induced motions (VIM) is a severe engineering problem for floating structures with slender columns. Moreover, recent studies on VIM of multi-column floating platforms showed that VIM also involves prominent yaw motions. In this paper, numerical simulations of VIM for a paired-column semi-submersible with transverse, inline and yaw degree-of-freedom are performed by our in-house CFD solver naoe-FOAM-SJTU. To avoid mesh distortion induced by yaw motion, a multi-block overset mesh is applied for the fluid domain. In order to accurately predict the flow separation and wake flow, the SST-DDES turbulence model is utilized. Vortex-induced yaw (VIY) is observed during VIM simulations. For high current velocity cases, multi-frequency component for yaw is discovered. The variation of yaw frequencies at different reduced velocities and current headings are discussed. Drag and lift, as well as rotational moment on each column member are analyzed.
Computational Fluid Dynamics (CFD)
Paired column semi submersible
Vortex induced yaw motions