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Influence of Finite Span and Sweep on Active Flow Control EfficacyActive flow control efficacy was investigated by means of leading-edge and flap-shoulder zero mass-flux blowing slots on a semispan wing model that was tested in unswept (standard) and swept configurations. On the standard configuration, stall commenced inboard, but with sweep the wing stalled initially near the tip. On both configurations, leading-edge perturbations increased CL,max and post stall lift, both with and without deflected flaps. Without sweep, the effect of control was approximately uniform across the wing span but remained effective to high angles of attack near the tip; when sweep was introduced a significant effect was noted inboard, but this effect degraded along the span and produced virtually no meaningful lift enhancement near the tip, irrespective of the tip configuration. In the former case, control strengthened the wingtip vortex; in the latter case, a simple semi-empirical model, based on the trajectory or "streamline" of the evolving perturbation, served to explain the observations. In the absence of sweep, control on finite-span flaps did not differ significantly from their nominally twodimensional counterpart. Control from the flap produced expected lift enhancement and CL,max improvements in the absence of sweep, but these improvements degraded with the introduction of sweep.
Document ID
20080023920
Document Type
Preprint (Draft being sent to journal)
Authors
Greenblatt, David (Technion - Israel Inst. of Tech. Haifa, Israel)
Washburn, Anthony E. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2008
Subject Category
Aerodynamics
Funding Number(s)
WBS: WBS 305311.43
Distribution Limits
Public
Copyright
Public Use Permitted.

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