Wing-sails의 공력 해석과 최적 설계

Abstract

The sailing ship is a eco-friendly vessels that using wind energy to produce the additional thrust by the hull above the wing-sails. In this study, we performed the aerodynamic analysis around wing-sails by considering the interaction of wing-sails in fixed angle of attack. The wind direction that produces the maximum thrust of wing-sails can be obtained by calculating the thrust of wing-sails with respect to the wind direction. In the aerodynamic analysis, we used three-dimensional compressible Navier-Stokes equation and hybrid grid to predict more viscous flow of boundary layer. We investigated that the maximum thrust of wing-sails at wind direction of 90 degree. After studying on the flow characteristic around wing-sails and effect of interaction, through derivative free based genetic algorithm and kriging surrogate model method to substitute a objective function evaluation we searched the optimal angle of attack that maximize the thrust of wing-sails. The result of optimization about wind direction of 45, 90 and 135 degree, we acquired about 7~23% of trust increment with trend of increasing the rear wing-sails’s angle of attack by the interaction of wing-sails. Also we confirmed the thrust enhancement of 2~18% by conducting a three-dimensional validation.