Wind turbine ice throw dynamics and aerodynamic interactions: A 6-DOF computational and statistical model for unsafe area identification

Abstract

The phenomenon of ice throw from modern wind turbines in cold regions poses significant safety and financial risks. This study develops a six-degree-of-freedom numerical model to predict the trajectory, rotation, velocity, and impact areas of ice fragments. The mathematical model is solved using Euler angles, Newton's second law, and Euler's laws of motion, and implemented using the Runge-Kutta method. This approach offers greater accuracy in simulating translation and rotation compared to previous methods. The study also provides a detailed examination of the concept of apparent mass and analyzes its effect along with the influences of angular velocity, aerodynamic forces and moments, wind velocity, and ice mass. Average values for lift, drag, and moments are generally considered. However, Theodorsen's unsteady lift is also considered in this study to examine the effect of apparent mass. The results of this study are used to identify unsafe areas around turbines, and the importance of identifying these areas is highlighted through a case study of a real turbine located near a highway. Finally, Monte Carlo simulations and random data were used to more accurately assess the simultaneous impact of various parameters on the unsafe areas around the turbines. The analysis shows that using 3000 samples provides a reliable estimate of the consequence distance with stable mean and standard deviation values. Increasing the number of samples beyond 3000 results in only marginal improvements in accuracy while significantly increasing computational costs. Therefore, 3000 samples represent an optimal balance between precision and efficiency in risk assessment. The findings of this study can be utilized for optimizing turbine placement and minimizing risks in cold climate conditions.