Dynamic and Static Characterization of Horizontal Axis Wind Turbine Blades Using Dimensionless Analysis of Scaled-Down Models

Abstract

The blade is the most important part of the horizontal axis wind turbine. As significant as its role in the efficient function of the turbine, stands the accurate predictions of static and dynamic performances of blades during the design phase for further developments. The objective of the current research is to develop a reliable approach, in which measurements and analysis of a scaled-down model can be used to predict the performance of full-scale wind turbine blades. The Buckingham π–Theorem has been applied to develop such approach. Two cases of the scaled-down models were investigated. The first case was a 0.3 m long adequate scaled-down blade built using 3D printing technology. This scaled-down model was examined experimentally and numerically to obtain dynamic characteristics then the measurements were used to predict the dynamic characteristics of 7 m long full-scale blade and validating its numerical model. Good agreement was found between the predictions of the full-scale blade and its numerical solutions.The second case was using the numerical model of scaled-down similitude of the full-scale blade. Tip deflection analysis and modal analysis were performed on the numerical model of similitude. Results were used to predict and validate the numerical solutions of the 7 m full-scale blade.  Better agreement was obvious.

Keywords

• Wind turbine blades; Dimensionless analysis; Buckingham π–theorem; Dynamic characteristics; Tip deflection; Modelling; 3D printing technology; Similitude theorem.

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