Determination of the angle of attack on the mexico rotor using experimental data

The reliability of airfoil data is an important factor to improve the prediction accuracy of aerodynamic loads and power using a Blade Element Momentum (BEM) code. The method of determination of angle of attack on rotor blades developed by Shen et al was successfully used to extract airfoil characteristics from experimental data on the MEXICO (Model Experiments in controlled Conditions) rotor.

Detailed surface pressure and Particle Image Velocimetry (PIV) flow field at different rotor azimuth positions were examined for determining the sectional airfoil data. It is worthwhile noting that the present technique uses simultaneously both PIV data and blade pressure data that include the actual flow conditions (for example, tunnel effects), so it is advantageous over other techniques that use only the blade loading (pressure data). the extracted airfoil data is put into a BEM code and the calculated axial and tangential forces are compared to those from BEM computations with Glauert's and Shen's tip loss correction models and experimental data.

The comparisons show that the present method of determination of AOA is correct, and the recalculated forces have good agreement with the experiment.