Journal ArticleDOI
Added-mass force on elliptic airfoils
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In this paper, exact algebraic expressions for the added-mass forces on elliptic airfoils are derived for any two-dimensional motion embedded in a steady free-stream flow.Abstract:
Herein, exact algebraic expressions for the non-circulatory (added-mass) forces on elliptic airfoils are derived for any two-dimensional motion – including simultaneous rectilinear acceleration and rotation – embedded in a steady free-stream flow. Despite the lengthy history of the added-mass concept and its widespread application to cylinders of various cross-sections, such closed-form expressions for elliptic cylinders, in terms of kinematic and geometric parameters alone, have remained absent from the literature until now. Inspection of the derived equations reveals that for pure pitching about a point on the chord-line, increasing thickness always decreases the added-mass force magnitude. For any given motion of the chord-line, the difference in force between thick and thin airfoils is proportional to the square of the thickness, although this difference may be positive or negative for the general three-degree-of-freedom case. In the special case of zero thickness and small pitch angles, Theodorsen's added-mass lift force on rigid thin airfoils is recovered; for large pitch angles, an exact generalization of Theodorsen's expression, applicable to the chord-normal direction, is given.read more
Citations
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Vortex-induced vibration forever even with high structural damping
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References
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General Theory of Aerodynamic Instability and the Mechanism of Flutter
TL;DR: In this paper, the Kutta condition was used to analyze the aerodynamic forces on an oscillating airfoil or an air-foil-aileron combination of three independent degrees of freedom.
Journal ArticleDOI
Vortex-induced vibrations
TL;DR: In this paper, a review summarizes fundamental results and discoveries concerning vortex-induced vibration (VIV) that have been made over the last two decades, many of which are related to the push to explore very low mass and damping, and to new computational and experimental techniques that were hitherto not available.
Journal ArticleDOI
Airfoil Theory for Non-Uniform Motion
Th. von Kármán,W. R. Sears +1 more
TL;DR: In this paper, the lift and moment acting upon an airfoil in the two-dimensional case may be calculated directly from simple physical considerations of momentum and moment of momentum after a calculation of the induction effects of a wake vortex.
Journal ArticleDOI
Parametric Study of an Oscillating Airfoil in a Power-Extraction Regime
Thomas Kinsey,Guy Dumas +1 more
TL;DR: In this article, the theoretical performance of a wing that is heaving and pitching simultaneously was investigated through unsteady two-dimensional laminar flow simulations using the commercial finite volume computational fluid dynamics code FLUENT.