Comparison of Potential Flow Wake Models for Horizontal-Axis Wind Turbine Rotors

摘要

Potential flow (PF) methods are a promising alternative to mainstream wind turbine aerodynamics tools such as blade element momentum (BEM) methods and mesh-based computational fluid dynamics (CFD) approaches. PF is relatively easy to setup and robust with respect to geometry. The advent of the fast multipole method (FMM) brings computational speed to PF methods. These attributes make PF suitable for integration with multidisciplinary design optimization (MDO) tools. A C++ library employing a Weissinger lifting-line model and several PF wake models has been developed. The library utilizes FMM to accelerate the N-body computation of PF element interactions. This paper compares the numerical accuracy and computational speed of PF wake models according to their compositions of vortex particles, filaments, and sheets. A standard three-bladed horizontal-axis wind turbine (HAWT) wind rotor under steady tower-free operation and prescribed elliptic circulation is presented. The effects of numerical artefacts such as wake discretization, truncation, and FMM tuning parameters are explored. Finally, computational speed enhancement is confirmed.