A series of numerical simulations were carried out to investigate the current generation performance in deepwater ocean engineering basin (DOEB) of KRISO. In the numerical simulations, unsteady Reynolds averaged Navier-Stokes (RANS) equations were solved to study the flow characteristics of the current generated in the basin. Three different current profiles, i.e. uniform, Gulf of Mexico (GoM) and Brazil profiles, were directly generated by applying the same current generation system as the DOEB and their accuracy was examined. In addition, an optimization algorithm based on cost function is newly proposed to control the inlet and outlet velocities of the multiple culverts for the desired current velocity profile. Through various numerical simulations, discussion are made on free surface elevation, effect of initial ramping operation, effect of false bottom plate, and full 3D simulation.
Nowadays, large amount of the total global production of oil and gas is composite of offshore resources which only may be reached with the help of new floating structures such as Floating Production Storage and Offloading (FPSO), Tension Leg Platform TLP, and SPAR platform, among others. Offshore systems are exposed to extreme environmental conditions for example wind, current and waves.
Current accounted largely in the total load of offshore systems with deep draft such as SPAR platforms. Risers experience vortex induced vibrations (VIV) due to current loads. Floating systems are affected by different current loads based on its depth and location in the world. Current velocity profile in Brazil, North Sea, Gulf of Mexico, Caspian Sea, Persian Gulf, and Yellow Sea among others have been monitored and studied. Characteristics of current velocity profiles were recognized at each particular site.
Hydrodynamics performance of offshore structures due to current loads are investigated through scaled model test. Current loads are modeled mainly in towing tank by towing the model at constant speed and ocean basin through a local jet and other techniques; however, previous method may model only uniform current profile and realistic current profiles cannot be generated. Therefore, some institutions and universities built a new kind of facilities which can generate more realistic environmental loads. Characteristics of these new facilities are described in Alho et al. (2008), Lu et al. (2010), and Bucher and de Wilde (2008). Representative numerical and experimental studies performed are presented next.
