Abstract
The following paper presents key findings from the Empire Wind monopile model tests. The tests were performed at SINTEF Oceans test facilities in late 2021 and early 2022 as part of FEED and early Detailed Engineering. Due to harsh weather conditions, with the potential for tropical hurricanes, combined with large monopile WTGs (Wind Turbine Generator), an extensive hydrodynamic test campaign has been conducted. The reason for this has been to test and validate the loads and response modes during extreme wave conditions over a variation of highly nonlinear sea states. This further allows for comparison with numerical analyses applied in both FEED and detailed design. As the Empire Wind WTGs are in waters occasionally visited by hurricanes, the attention to extreme events in a low damping configuration has been of particular interest. This implies global response due to ringing and slamming, as well as local effects from runup. Providing an accurate and representative description of such responses, is important. This is particularly true when dynamic properties of the WTGs are moved closer to the wave frequent area. This has also called for more advanced numerical methods to capture both the nonlinear irregular waves and the global structural response. The paper gives and introduction to both the model tests, and comparisons with the numerical analyses. Focus is placed on wave responses from selected sea states along the 50 and 500 year contours.
