Experimental investigation of variations of simulated ice shapes on aerodynamic performance of a finite wing

Abstract

A multi-entry experimental study was conducted to investigate the effects of roughness, simulated ice shapes, and various combinations of roughness and simulated shapes on aerodynamic performance of a reflection plane wing model. All testing was conducted at the Wichita State University 7 ft by 10 ft wind tunnel facility. Roughnesses tested included 12, 16, 20, 24, 40, 80 and 100 grit sandpaper in coverages including 5%c on the lower surface to 5%c on the upper surface, 10%c on the lower surface to 10%c on the upper surface, and 20%c on the lower surface to 20%c on the upper surface. Simulated ice shapes tested included 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, and 12.7 mm quarter round step ice shapes along with a 1 mm round ice shape. Locations for step ice placement included 1%c, 3%c, 5%c, 8%c, 10%c, 12%c, 15%c, 20%c, 25%c, and 36%c on the upper surface in addition to 1%c, 5%c, 10%c, and 15%c on the lower surface. Combinations of step ice and roughness to simulate observed ice shapes from an icing tunnel test and an aluminum leading edge ice shape to simulate a long growth ice accretion were also investigated. The various components of the simulated configurations were varied do ascertain which features drove performance degradation. Results indicated that most configurations decreased the slope of the lift curve. CLstall was reduced by as much as 46.5% with respect to the clean wing when the SI12-15-US configuration was installed on the wing. At the other end of the range of changes to CLstall, the SI4-15-US configuration caused an increase of 12%. The leading edge ice shape caused the largest movement in aerodynamic center of any configuration tested. The largest increase in minimum drag was seen with the LEice-R10 configuration at an increase of nearly 110%. All ice shapes exhibited a positive slope for the CM curve with the leading edge ice shape having the highest observed slope. Control surface deflections had a relatively uniform impact on all aerodynamic forces impact regardless of the installed ice shape. Installations of simulated ice shapes on the lower surface primarily impacted drag performance with minimal degradation to lift performance.