Boundary-Layer Flow Effects on Aerodynamic Performance of Forward-Swept Wings
Publication: Journal of Aerospace Engineering
Volume 25, Issue 4
Abstract
The effects of a forward-sweep angle (), Reynolds number (), and angle of attack () on the boundary-layer flow and aerodynamic performance of a finite forward-swept wing (NACA 0012 airfoil) were experimentally investigated. The Reynolds number and the forward-sweep angle were and , respectively. The chord length was 6 cm, and the semiwing span was 30 cm; therefore, the semiwing aspect ratio was 5. The boundary-layer flow structures were visualized using the surface-oil-flow technique. Seven boundary-layer flow modes were identified by changing , , and : separation, separation bubble, secondary separation, leading-edge bubble, three-dimensional ()/bubble-extension flow, and bluff-body wake modes. Furthermore, a six-component balance measured the aerodynamic loadings. The aerodynamic performance related closely to the boundary-layer flow modes. The dimensionless bubble length () indicated that a high forward-sweep angle conducted a longer bubble length than that at a low forward-sweep angle. The pseudostall occurred in the bubble-extension mode, while , and of 19.5° at was about 1.16-fold larger than that of 9° at as . Namely, the forward-sweep angle retards the stall.
Get full access to this article
View all available purchase options and get full access to this article.
References
Abbott, I. H., and von Doenhoff, A. E. (1959). Theory of wing section, Dover, New York.
Bertin, J. J., and Smith, M. L. (1989). Aerodynamics for engineers, 2nd Ed., Prentice Hall, Englewood Cliffs, NJ.
Breitsamter, C., and Laschka, B. (2001). “Vortical flowfield structure at forward swept wing configurations.” J. Aircr., 38(2), 193–207.
Hoerner, S. F. (1958). Fluid-dynamic drag: Practical information on aerodynamic drag and hydrodynamic resistance, 2nd Ed., Hoerner Fluid Dynamics, Midland Park, NJ.
Hoerner, S. F., and Borst, H. V. (1975). Fluid-dynamic lift: Practical information on aerodynamic and hydrodynamic lift, Hoerner Fluid Dynamics, Brick Town, NJ.
Huang, R. F., and Lin, C. L. (1995). “Vortex shedding and shear-layer instability of wing at low-Reynolds numbers.” AIAA J., 33(8), 1398–1430.
Mueller, T. J. (1983). “Flow visualization by direct injection.” Fluid mechanics measurements, 1st Ed., R. J. Goldstein, ed., Hemisphere, New York, 307–340.
Mueller, T. J., and Delaurier, J. D. (2003). “Aerodynamics of small vehicles.” Annu. Rev. Fluid Mech. 35, 89–111.
Nangia, R. K. (1982). “Aspects of forward swept wing research at the University of Bristol.” Proc. Int. Conf. Forward Swept Wing Aircr., Univ. of Bristol, Bristol, U.K., I.9.1–I.9.24.
Redeker, G., and Wichmann, G. (1991). “Forward sweep—A favorable concept for a laminar flow wing.” J. Aircr., 28(2), 97–103.
Squire, L. C. (1961). “The motion of a thin oil sheet under the steady boundary layer on a body.” J. Fluid Mech., 11(2), 161–179.
Weeks, T. M., and Leet, L. H. (1982). “The X-29A forward swept wing advanced technology demonstrator program.” Proc. Int. Conf. Forward Swept Wing Aircr., Univ. of Bristol, Bristol, U.K., I.1.1–I.1.8.
Yen, S. C., and Huang, L.-C. (2009). “Flow patterns and aerodynamic performance of unswept and swept-back wings.” J. Fluids Eng., 131(11), 111101–111111.
Information & Authors
Information
Published In
Copyright
© 2012 American Society of Civil Engineers.
History
Received: Jan 2, 2011
Accepted: Jun 13, 2011
Published online: Jun 15, 2011
Published in print: Oct 1, 2012
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.