T. Ikeda, T. Ueda, Nagoya University, Nagoya, Japan; S. Masuda, IHI Corporation, Yokohama, Japan
A Smart Vortex Generator (SVG) concept for aircraft has been proposed, where SVG autonomously transforms between an upright vortex-generating position in take-off and landing and a flat drag-reducing position during a cruise. This SVG is made of shape memory alloy (SMA), and super-elasticity and shape memory effect of SMA and approximately 70 K difference in ambient temperature between a cruise altitude and a ground are harnessed to transform. SMA in SVG is in austenite phase and memorizes the upright position at higher temperatures in the take-off and landing. At low temperatures during ascent SMA transforms into a martensite phase, and SVG lies flat against a base structure due to external or/and internal forces. In this paper, two types of external forces are examined for the transformation into the drag-reducing position. One is a counter spring to be hooked to SVG, and the other is an aerodynamic force being applied to SVG during flight. To analyze deformation behavior of SVG, numerical simulations are performed using a simplified mathematical model composed of an SMA line element with an applied stress corresponding to the two forces. The aerodynamic force is calculated by a commercial CFD program. Numerical results show that this SVG can transform between the two positions when the counter spring is used. When the aerodynamic force is harnessed, SVG can take a drag reducing position, but is not flat, by reducing the stiffness of SVG.
