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The initial lift and drag of an impulsively started airfoil of finite thickness

Published online by Cambridge University Press:  20 April 2006

Chuen-Yen Chow
Affiliation:
Department of Aerospace Engineering Sciences, University of Colorado, Boulder, Colorado 80309, USA
Ming-Ke Huang
Affiliation:
Department of Aerospace Engineering Sciences, University of Colorado, Boulder, Colorado 80309, USA

Abstract

The method of apparent masses is utilized to compute the initial lift and drag of an airfoil that starts impulsively from rest. Analytical solutions are obtained for in viscid incompressible flow past a slightly cambered airfoil at a small angle of attack. For a Joukowski airfoil with a cusped trailing edge, it is found that increasing camber or angle of attack will cause increases in both initial lift and drag, whereas increasing thickness will result in an opposite effect. Effects of trailing-edge angle are examined by considering the symmetric Kármán-Trefftz airfoil. The result shows that both lift and drag vanish at the initial instant if the airfoil has a finite trailing-edge angle.

Type
Research Article
Copyright
© 1982 Cambridge University Press

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References

Basu, B. C. & Hancock, G. J. 1978 The unsteady motion of a two-dimensional aerofoil in incompressible inviscid flow. J. Fluid Mech. 87, 159178.Google Scholar
Garrick, I. E. 1957 Non-steady wing characteristics. High Speed Aerodynamics and Jet Propulsion, vol. VII, section F. Princeton University Press.
Giesing, J. P. 1968 Nonlinear two-dimensional unsteady potential flow with lift. J. Aircraft 5, 135143.Google Scholar
Giesing, J. P. 1969 Vorticity and Kutta condition for unsteady multienergy flows. Trans. A.S.M.E. E, J. Appl. Mech. 91, 608613.Google Scholar
Jones, R. T. 1939 The unsteady lift of a wing of finite aspect ratio. NACA Rep. no. 681.Google Scholar
Kärmán, T. Von & Burgers, J. M. 1943 General aerodynamic theory - perfect fluids. Aerodynamic Theory, vol. II, division E. Durand Reprinting Committee, California Institute of Technology.
Kármán, T. Von & Sears, W. R. 1938 Airfoil theory for non-uniform motion. J. Aero. Sci. 5 617.Google Scholar
Nielsen, J. N. 1960 Missile Aerodynamics. McGraw-Hill.
Pope, A. 1951 Basic Wing and Airfoil Theory. McGraw-Hill.
Wagner, H. 1925 Über die Entstehung des dynamischen Auftriebes von Tragflügeln. Z. angew. Math. Mech. 5, 1735.Google Scholar