TORQUE2026: Can the second tower mode become significant for fatigue loads of offshore wind turbine monopiles?

This repository presents the results of time domain simulations performed for three different reference wind turbines; the IEA 10 MW, IEA 15 MW, and IEA 22 MW, as part of a contribution for the 2026 edition of the TORQUE conferene. The simulations were performed with the aeroelastic software ASHES 3.31 and the here included data are the raw result of these simulations. The following assumptions were made for the simulations: The turbines are clamped at the mudline in a water depth of 40 m. Soil-Structure interaction is thus not included. Structural damping was included as Rayleigh damping with a damping ratio of 1 % for the first tower mode and 2 % for the second tower mode. Simulations were performed for a length of 700 s of which the first 100 s should be taken as an initial transient period. Simulations were performed for three wind-wave misalignment directions: Wind-wave aligned, 0 degrees. Wind-wave misaligned, 15 degrees. Wind-wave misaligned, 30 degrees. Simulations were performed with 6 seeds for wind and wave. Simulations were performed at rated wind speed for each turbine with turbulent wind based on the normal turbulence model (NTM) Simulations were performed with regular waves based on JONSWAP. Results were obtained for beam, node, and fatigue sensors at various locations along the monopile as well as tower top and tower bottom. Furthermore, results were also obtained from the rotor and sea sensor. See Ashes user manual for more details about sensors in Ashes The following metocean conditions were used for the simulations: Turbine Wind speed [m/s] Significant wave height [m] Peak wave period [s] IEA 10 MW 11 1.24 4.97 IEA 15 MW 10.59 1.05 4.59 IEA 22 MW 11 1.11 4.71 The following figure and table show the sensor locations along the monopile. Elevation [mSWL] IEA 10 MW IEA 15 MW IEA 22 MW 15 - MP1 MP1 10 MP1 - - 0 MP10/MP11 MP15/MP16 MP15/MP16 -20 MP30/MP31 MP35/MP36 MP35/MP36 -40 MP50 MP55 MP55