Phenomenological models for post-stall airfoil characteristics of horizontal-axis wind turbines

Abstract

There exist significant differences in airfoil aerodynamic characteristics between wind tunnel test data (2-Dimensional flow) and field test data (3-D dimensional flow). Through the Combined Experiment Program (CEP), efforts have been made to investigate proper approaches to analyze such differences so that it enables us to incorporate the results into wind turbine rotor performance codes to assist in optimal design of a horizontal axis wind turbine. As a step towards a more indepth, theoretical analysis of various physical effects under field conditions, we first analyze the difference in airfoil characteristics from phenomenological point of view by developing correlations from experimental data. The correlations for the difference in lift coefficient and drag coefficient between 2-dimensional and 3-dimensional flow are developed to form a basis and are suggested to be modified and included in the PROP code.