Three dimensional rectangular wing morphed to prevent stall and operate at design local two dimensional lift coefficient

Abstract

The surface of a rectangular wing is morphed at high angles of attack such that it continues to operate at the reduced coefficient of lift (Cl) at which the baseline wing operates, but unlike the baseline wing, where the flow is separated, the flow remains attached on the morphed wing. A morphed surface is also generated to operate at a local design 2D (two-dimensional) Cl, which is obtained by incrementing the baseline Cl by a percentage at pre and post-stall angles of attack. The morphed surface is generated numerically using a novel ‘decambering’ technique, which accounts for the deviation of the coefficients of lift and pitching moment from that predicted by potential flow, analytically, using CFD and implemented experimentally by attaching an external Aluminium skin to the leading edge of the wing. Two different wing sections, NACA0012 and NACA4415, are tested on a rectangular planform. The effect of morphing on the aerodynamic performance is discussed, and aerodynamic characteristics are reported. Results indicate that significant improvement in aerodynamic performance is achieved at high angles of attack, especially at post-stall through this active morphed flow surface.