Numerical analysis on the aerodynamics of HAWTs using nonlinear vortex strength correction

Nonlinear vortex strength correction method (NVCM) based on potential flow, is developed for improvement of vortex lattice method which has difficulties to predict the separated flow conditions and the viscous effect. In this method, the bound vortex strength is determined by matching the lift force from VLM with the lift force from aerodynamic coefficients table as the same value of circulation is added to or subtracted from all chord wise vortices. For considering the nonlinearities due to the neighboring sections of the blade, sophisticated Newton–Rapson algorithm is applied. The validation of this method was done by comparing the simulations with the measurements on the NREL Phase-VI horizontal axis wind turbine (HWAT) in the NASA Ames wind tunnel under uniform and yawed flow conditions. This method gives good agreements with experiments in most cases.