*Dept. of Ocean Engineering, Mokpo National University, Mokpo, Korea**School of Naval Architecture and Civil Engineering, Zhejiang Ocean University, Zhoushan, ChinaKEY WORDS: Computational fluid dynamics, Morison’s formula, High-order b oundary element method, Numerical wave tank, Wave load, Current load, Circular cylinder, Ocean wind turbine, Subs tructureABSTRACT: Numerical simulations were performed for the evaluation of wave and current loads on a fixed cylindrical substructure model for an ocean wind turbine using the ANSYS-CFX package. The numerical wave tank was actualized by specifying the velocity at the inlet and applying momentum loss as a wave damper at the end of the wave tank. The Volume-Of-Fluid (VOF) scheme was adopted to capture the air-wa ter interface. An accuracy validation of the numerical wave tank with a truncated vertical circular cylinder was accomplished by comparing the CFD results with Morison’s formula, experimental results, and potential flo w solutions using the higher-order boundary element method (HOB EM). A parametric study was carried out by alternately varying the length and amplitude of the wave. As a meaningful engineering appl ication, in the present study, three kinds of conditions were considered, i.e., cases with current, waves, and a combination of current and progressive waves, passing through a cylindrical substructure model. It was found that the CFD results showed reasonable agreement with the results of the HOBEM and Morison’s formula when only progressive waves were consider ed. However, when a current was included, CFD gave a smaller lo ad than Morison’s formula.Corresponding author Wu-Joan Kim: 1666 Youngsan-ro, Cheonggye-m yeon, Muan-gun, Jeonnam, Korea, 061-450-2766,kimwujoan@mokpo.ac.kr