Influence of the Curved Ground Surface on the Lift of Flat Plate Airfoil

Abstract:

At present, only the flat ground surface problem is investigated in most studies on ground effect, which is not effective for practical applications due to the universal existence of curved ground surface. In this paper, the lift calculation of a two-dimensional flat plate airfoil placed near a curved ground surface is investigated. In order to calculate the complex velocity in the flow field, the complex variable function theory is employed. The conformal mapping method is applied to transform the flat plate airfoil to a cylinder in the uniform flow. Moreover, the discrete vortices method is modified to convert the curved ground surface to a series of discrete boundary elements. Two kinds of curved ground surfaces are considered: semicylindrical hollows and semicylindrical hills. It is shown that the lift fluctuation of flat plate airfoil located near a hollow or a hill is considerably serious, which should be considered during the design of flight vehicles flying near the ground surface.

• Periodical: Applied Mechanics and Materials (Volume 232)
• Pages: 261-266
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.232.261
• Online since: November 2012
• Authors: Shi Shi Chen, Fen Fen Xiong, Vladimir A. Frolov, Ke Yong Li
• Keywords: Complex Variable Function, Conformal Mapping, Curved Ground Surface, Discrete Vortices, Ground Effect

References

[1] C. Wieselsberger: Wing Resistance Near the Ground, NACA TM77, (1922).

[2] S. Tomotika, T. Nagamiya and Y. Takemouti: The Lift on a Flat Plate Placed Near a Plane Wall with Special Reference to the Effect of the Ground upon the Lift of a Monoplane Aerofoil, Aeronautical Research Institute, Vol. 8, No. 97, Tokyo, Japan (1933).

[3] L.G. Ivanteeva, S.I. Konovalov and G.A. Pavlovets: Calculation of Aerodynamic Characteristics of the Foil Near the Ground for Given Magnitudes of its Geometric Parameters, Proceedings of Central Aerohydrodynamics Institute, Vol. 11, No. 2, (1980).

[4] A.G. Terentiev and T.V. Kartuzova: Numerical Investigation of Flow over Airfoil Near the Ground, Proceedings of the National Academy of Sciences and Arts of the Chuvash Republic, No. 6, (1996), pp.94-104. (in Russian).

[5] E.L. Houghton and P.W. Carpenter: Aerodynamics for Engineering Students (5th Edition), Butterworth-Heinemann, Oxford, Great Britain (2003), pp.160-171.