Long-Term Simulation of Turbulence-Induced Loads Using the SNLWIND-3D, FAST, YawDyn, and ADAMS Numerical Codes

Notable progress was made in simulating the dynamic response of operating wind turbines during the past several years. In concert with these activities, the ability to adequately simulate the characteristics of the turbulent inflow, which is directly or indirectly responsible for much of the observed response, has also improved significantly. Recent investigations have shown that without such inflow simulations, it is often difficult to predict fatigue-load distributions that agree with observations. In this paper we discuss the results of a numerical experiment in which we simulated representative diurnal variations in the inflow environments for two distinct locations within a multi-row wind farm: upwind of the first and downwind of the last row of turbines. With the SNLWIND-3D turbulence simulation code, we created a series of 144, 10-minute inflow records that are likely to occur individually within a 24- hour period at each location. An upwind, rigid-hub, three-bladed turbine was modeled with the Yaw Dynamics (YawDyn) and Automatic Dynamic Analysis of Mechanical Systems (ADAMS) simulation codes while a downwind, teetered-hub, two-bladed turbine was simulated with the Fatigue, Aerodynamics, Structures, and Turbulence (FAST) code and ADAMS. We found good to excellent agreement between the codes themselves in predicting the flapwise bending load spectra, and with limited test data.