The invention discloses a long flexible blade reduced
scale model design method suitable for a large fan wind tunnel experiment. The method comprises the following steps: selecting a reasonable
similarity criterion, selecting a section airfoil of a model blade, optimizing the distribution of chord length and torsion angle in the length direction of the blade, and optimizing a model rotor variable
pitch control strategy; the design objectives that the
thrust coefficient of the reduced-
scale model rotor in the experimental
wind speed range is equal to that of the original-size fan rotor in the corresponding original-size
wind speed range, and the first-order inherent frequency in the
flapping and shimmy directions of the blades of the reduced-
scale model is equal to that of the original-size blades are achieved, and the long flexible blade reduced-scale model is provided for a large-scale fan wind tunnel experiment. According to the method, the first-order inherent frequency of the
flapping and shimmy directions of the model blade and the blade of the original size is equal, the thrust coefficients are equal under multiple working conditions, the wind tunnel experiment
similarity criterion is met, different airfoil choices are appointed for different
design control sections, and the method has high optimization solution efficiency.