Stefan Puttinger, Andreas Mehrle, Walter Meile, Philipp Gittler,
"Numerical Optimization and Experimental Investigations on the Principle of the Vortex Diffuser"
, in Journal of Aircraft, Vol. 48, Nummer 3, Seite(n) 845-854, 2011, ISSN: 1533-3868
Original Titel:
Numerical Optimization and Experimental Investigations on the Principle of the Vortex Diffuser
Sprache des Titels:
Englisch
Original Kurzfassung:
The present work deals with numerical optimization of and experimental studies on aftmounted wingtip devices, or so-called vortex diffusers. The purpose of most kinds of wingtip devices is to reduce the induced drag by converting vortex energy into thrust. To obtain an optimal design for the vortex diffuser, the parameterized diffuser blade shape is optimized with respect to axial thrust within the framework of the lifting-line theory. Finite airfoil performance is accounted for by applying lift and drag coefficients from wind-tunnel data. The so-gained optimal design for the vortex diffuser blades is realized on a small-scale model, and wind-tunnel tests are carried out to investigate drag reduction of the vortex diffuser for comparison with numerical results. Furthermore, the goal is to gain some experience and data for preparation of real flight testing on an unmanned aerial vehicle. As the vortex diffuser can produce forces and moments in all three directions, a pure wing?body configuration with vortex diffusers instead of rudder, elevator, and ailerons would be possible. The wind-tunnel tests also deliver data to investigate basic flight mechanics of such a configuration. In the case of asymmetric vortex roll up, the paper demonstrates a way to optimize the vortex diffuser settings online in the wind tunnel. Experiments clearly show that the vortex diffuser is able to reduce drag in high-lift/high-angle-of-attack configurations. Wind-tunnel tests, however, also demonstrate some problems for practical design of the vortex diffuser.
Forschungs-