Hydrodynamic Forces for HVDC Cable Bundles Under Wave and Steady Current Conditions

A collaborative study between The University of Western Australia (UWA), Southern Cross University (SCU), Aurora Offshore Engineering (AOE) and Jan de Nul (JDN) was undertaken to investigate the hydrodynamic forces experienced by a single cable and cable bundle at various angular orientations under steady and oscillatory flow conditions. Physical model testing was undertaken at the UWA Large O-Tube (LOT) Facility, which is located at UWA’s Coastal Ocean Research Laboratories (CORL). This testing was conducted at 1:1 scale, with the capacity of the O-Tube able to replicate flow conditions relevant for design. Computational Fluid Dynamics (CFD) modelling was undertaken to complement the physical testing and aid in interpretation of the results, including flow visualization and accounting for the effects of flow blockage in the water flume. These test results represent novel contributions to the understanding of hydrodynamic forces for HVDC single pipe and bundle configurations accounting for the influence of a number of critical flow parameters, including Reynolds number (current velocity), Keulegan-Carpenter number (wave characteristics), surface roughness (pipe features), incoming turbulence intensity and bundle orientation. It is anticipated that these improvements in understanding contribute very helpfully to improving the safe workable range of metocean conditions in which these cables may be installed, lowering the risks of cable damage and improving the costs of installing the cables.