| Summary: | 碩士 === 國立虎尾科技大學 === 飛機工程系航空與電子科技碩士班 === 106 === Closed wing has the advantage including low weight, high stiffness, low induced drag and good stability, and has great potential for development of HALE Solar UAV. This study focuses on reducing the structure weight as well as enhancing stability of maneuverability and environmental tolerance without comprising aerodynamic characteristics. The effects of configuration parameters and installation arrangement of the closed wing designed under different operational conditions have been discussed in detail for the aerodynamic performance. The 3D numerical simulation integrated SST k-ω turbulence module is performed to investigate the aerodynamic characteristics of closed wing in different vertical and horizontal distances of upper and lower wing, and the swept angle of lower wing.
The wing tip vortex influence to closed wing is less than SINGLE WING. For rectangular closed wings with 0≦D/c≦6 and 0.5≦H/c≦2, the CL grows as H/c increases initially and saturate as H/c=1.5 when D/c is fixed. Meanwhile, the CL grows as D/c increases when H/c is fixed. Comparing with the single wing, the average CL are 88.4%, 93%, 94.8% and 101.4% of SINGLE WING as D/c=0、1.5、3、6. For swept closed wings with 0≦D/c≦2, the CL decreases as D/c increases and D/c=0.5 has the best average CL. In the same aspect ratio, both L/Waf and L/W for BOXWING are all better than SINGLE WING. Comparing with the single wing, the maximum enhancement of L/Waf and L/W for BOXINNGWING are about 265% and 102%.
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