Topic
Lift-induced drag
About: Lift-induced drag is a research topic. Over the lifetime, 2861 publications have been published within this topic receiving 41094 citations.
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TL;DR: It was found that significant reductions in both the static and dynamic loads were possible, and a 25% increase in span using folding wing-tips resulted in almost no increase in loads.
Abstract: A recent consideration in aircraft design is the use of folding wing-tips with the aim of enabling higher aspect ratio aircraft with less induced drag while also meeting airport gate limitations This study investigates the effect of exploiting folding wing-tips in flight as a device to reduce both static and dynamic loads A representative civil jet aircraft aeroelastic model was used to explore the effect of introducing a wing-tip device, connected to the wings with an elastic hinge, on the load behaviour For the dynamic cases, vertical discrete gusts and continuous turbulence were considered The effects of hinge orientation, stiffness, damping and wing-tip weight on the static and dynamic response were investigated It was found that significant reductions in both the static and dynamic loads were possible For the case considered, a 25% increase in span using folding wing-tips resulted in almost no increase in loads
65 citations
TL;DR: In this paper, a flat plate placed upstream of and parallel to the cylinder has yielded an optimal geometrical configuration consisting of a plate height one-third the cylinder diameter placed 1.5 diameters upstream of the cylinder, and produces a system drag that is 38% that of the bare cylinder alone.
65 citations
64 citations
10 Dec 2002
TL;DR: In this paper, the authors applied new structured distributed control methods to an experimental apparatus representing aerial vehicles flying in close formation for the purpose of induced drag reduction, and found that the centralized controller will result in the smallest closed-loop gains, but that the distributed controller will perform substantially better than the decentralized controller.
Abstract: Applied new structured distributed control methods to an experimental apparatus representing aerial vehicles flying in close formation for the purpose of induced drag reduction. Four wings with roll and lateral degrees of freedom are set in a wind tunnel in a half-vee formation. Upon system identification via grey box modelling, the performance of three types of control were compared, by applying the control to a model of the experimental apparatus and to a simulation of a larger array of wings. The hypothesis states that the centralized controller will result in the smallest closed-loop gains, but that the distributed controller will perform substantially better than the decentralized controller. Experimental results support this hypothesis, so that the distributed, scheme can provide much of the performance of the centralized approach, while presenting a much more tractable synthesis problem.
63 citations
TL;DR: In this article, the effect of different jet strategies on the flow field properties has been investigated, and the obtained results show that the pentacle shape owns the best performance of the drag and heat reduction, and its value drops 23.6%.
63 citations