Heave damping of spar platform for offshore wind turbine with heave plate

Abstract

This paper presents the effects of heave plate on heave damping of spar with single and two heave plates for supporting the offshore wind turbine. Heave free decay tests are carried out experimentally on 1:50 scale model of spar with single and two heave plates for finding the heave damping. Heave dampings are also obtained numerically using Computational Fluid Dynamics (CFD) simulation and validated with the experimental results. Detailed parametric studies are conducted numerically on spar with single and two heave plates. Effects of scaling ratio (1–50), diameter ratio (1–2), heave plate position to diameter of heave plate ratio (0.2–1), heave plate position to draft ratio (0.2–0.8), relative spacing (0.2–1) and spacing between heave plates to draft ratio (0.2–0.8) are examined. Results show that the heave damping increases with increase in scaling ratio and diameter ratio. It is found that the diameter ratios of 1.2–1.4, position to diameter of heave plate ratio of 0.8, position to draft ratio of 0.4, relative spacings of 0.4–0.6 and spacing to draft ratios of 0.2–0.4 are more favorable conditions to reduce the heave motion.