Wind Turbine Simulations Using CPU/GPU Heterogeneous Computing

• Published in: International journal of aeronautical and space sciences Vol. 25; no. 2; pp. 331 - 344
• Main Authors: Jung, Yong Su, Baeder, James
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Society for Aeronautical & Space Sciences (KSAS) 01-04-2024; 한국항공우주학회
• Subjects: Aerospace Technology and Astronautics; Engineering; Fluid- and Aerodynamics; Original Paper; 항공우주공학; Blade–tower interaction; Boundary-layer transition; Horizontal-axis wind turbine; CPU/GPU CFD
• ISSN: 2093-274X; 2093-2480
• DOI: 10.1007/s42405-023-00677-2

In this study, a heterogeneous solution framework using both CPUs and GPUs was used to numerically simulate flow over the National Renewable Energy Laboratory (NREL) Phase IV horizontal-axis wind turbine. An in-house line-based unstructured flow solver implemented on CPUs was coupled to an in-house structured solver implemented on GPUs via a lightweight Python-based framework within an overset mesh system. First, computations were conducted for an isolated rotor at three different wind speeds of 7 m/s, 10 m/s, and 20 m/s, and subsequently full wind turbine simulations that included the nacelle and the tower. The entire system was used to understand the blade–tower interference on both upwind and downwind configurations, and the predictions were compared with the experimental data in terms of blade airloads. The effects of the laminar–turbulent transition were also investigated on a blade using the two-equation transition model coupled with Spalart–Allmaras turbulence model, whose inclusion resulted in a more accurate torque prediction. The downwind tower interaction was much more severe than the upwind interaction on the blade owing to its blade–wake interaction. Finally, a normal wind profile model was used to simulate the freestream wind shear during the wind turbine operation in an atmospheric boundary layer. Even a small variation in the wind speed resulted in a high level of unsteadiness in the blade airloads, which could generate vibratory loads on the wind turbine.