Introduction of the Virtual Center of Wind Pressure for correlating large-scale turbulent structures and wind turbine loads

Abstract. For modern wind turbines, the effects of inflow wind fluctuations on the loads are becoming increasingly critical. Using field measurements of a full-scale operating wind turbine and simulated loads calculated with reconstructed wind fields from wind measurements from the GROWIAN campaign, we identify particular load events that lead to high values of the so-called damage equivalent loads. Remarkably, the simulations do not reproduce such load occurrences when standard synthetic turbulent wind fields are used as inflow. These standard wind fields are typically parameterized by statistics at a single measurement location (e.g., mean wind speed and turbulence intensity). In this article, we introduce a new characteristic of a wind field: the virtual center of wind pressure. The new feature is calculated from averages of the thrust force acting on a defined area, i.e., the rotor area of the turbine. We correlate these characteristics to the unusual load events observed in the operational measured data. Furthermore, we demonstrate that the introduced concept is an efficient tool to characterize large-scale structures within wind fields. We propose using the virtual center of wind pressure in conjunction with the well-defined single-location properties to consolidate improved descriptions of atmospheric wind and more accurate wind fields for turbine simulations.