スピンするデルタ翼の空力特性について

Abstract

The experiments of a delta wing’s spin phenomena were conducted at the low speed wind tunnel of Nagoya University with its exit test section inclined vertically. The spin rate of the delta wing in the free rotation mode was measured as well as surface pressure distributions on the spinning delta wing. At low angles of attack the spin rate increases with sideslip angle, whereas near the stall angle, it decreases. At low angles of attack, when the wing has a sideslip angle, the upper surface pressures of the windward wing-half become lower than those of the leeward wing-half, while near the stall angle the latter become lower than the former. These asymmetric pressure distributions cause the spinning motion of the delta wing. It is evident from these pressure distributions and flow visualizations that a leading edge separation vortex makes an important role in spin phenomena of the delta wing. It is also found that at the equilibrium spin rate, the spanwise distribution of the pressure difference between upper and lower surfaces, ΔCp , shows a nearly symmetric pattern regarding the wing centerline.