Comparison of the Inflow Predictions of Three Wind Turbine Rotor Aerodynamic Analysis Codes

This document summarizes the research performed to date at the University of Illinois Wind Turbine System Design and Analysis Laboratory with developing a more accurate tip loss model for use with the blade element-momentum method. The calculation results indicate the Prandtl tip loss model over predicts the blade loading near the tip and under predicts it inboard of 80% span. The axially inducedflow calculated using traditional blade element-momentum theory together with the Prandtl tip loss model is compared with two separate methods that determine the wake effects (tip losses) directly. The computer code, PROPID, is used to calculate the rotor performance using blade element-momentum theory with the Prandtl tip loss model. The two performance predictions incorporating wake vortextheory are computed using RotorCRAFT and LSAF. The steps taken to validate the wake-based codes are described. Experimental data are presented for the vortex theory code validation.;