Author(s): Tuomo Karna; Helge Gravesen; Lennart Fransson; Sveinung Loset
Linked Author(s):
Keywords: No Keywords
Abstract: This paper addresses a condition where a vertical offshore structure is subjected to actions of level ice. We show first that the reactive actions posed by a wind farm or an offshore platform on the drifting ice floe may significantly influence the local ice speed. Second, a special-purpose software PSSII is used to simulate the dynamic response of a wind turbine structure to ice actions. The simulations show that the dynamic response to ice action is a complicated phenomenon in cases where the structure has several eigenmodes in the frequency range below 10 Hz. Our model predicts events where the superstructure experiences vibrations due to frequency lock-in at one of the lowest modes while to topside experiences similar vibrations at two other modes. Physical explanations to this complicated phenomenon are proposed and supported by experimental results.
Year: 2010