Open Access

ARTICLE

Performance Computations and Design Criterion of Airfoils in Unsteady Viscous Flows

Rosario M. A. Marretta¹, Giovanni Lombardi², Roberto Antinoro¹

1 Department of Mechanics and Aeronautics, Viale delle Scienze, 90128 Palermo, Italy.
2 Department of Aerospace Engineering, Via Caruso, 56122 Pisa, Italy.

Computer Modeling in Engineering & Sciences 2003, 4(1), 73-84. https://doi.org/10.3970/cmes.2003.004.073

Abstract

An approach based on Lighthill's transpiration velocity is explored and proposed for a new design criterion for airfoils in unsteady and viscous flows. This criterion confines its methodologies to the close proximity of the laminar and turbulent boundary layer and it shows good efficiency in predicting and calculating the wake evolution regions in a wide range of operating unsteady parameters. Also, the criterion is capable of predicting low Mach number, attached flow-fields as accurately as the full Navier-Stokes solutions when the massive flow separation is avoided. The agreement of the present results with those empirically and theoretically determined is very accurate for attached flows and well within the general range of the boundary layer correlations and the angles of attack of the airfoils. Finally, the proposed computational recursive scheme is unusually not sensitive to the order of discretization and the distribution of the nodes and, under the hypotheses of work, it makes possible a complete and quite well description of the vortical regions of the wake past the airfoil under several unsteady starting conditions which may be iterated to give accurate results reliability.

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Keywords

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