Applications of the unsteady vortex-lattice method in aircraft aeroelasticity and flight dynamics
Murua, J, Palacios, R and Graham, JMR (2012) Applications of the unsteady vortex-lattice method in aircraft aeroelasticity and flight dynamics Progress in Aerospace Sciences, 55. 46 - 72. ISSN 0376-0421
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The Unsteady Vortex-Lattice Method provides a medium-fidelity tool for the prediction of non-stationary aerodynamic loads in low-speed, but high-Reynolds-number, attached flow conditions. Despite a proven track record in applications where free-wake modelling is critical, other less computationally-expensive potential-flow models, such as the Doublet-Lattice Method and strip theory, have long been favoured in fixed-wing aircraft aeroelasticity and flight dynamics. This paper presents how the Unsteady Vortex-Lattice Method can be implemented as an enhanced alternative to those techniques for diverse situations that arise in flexible-aircraft dynamics. A historical review of the methodology is included, with latest developments and practical applications. Different formulations of the aerodynamic equations are outlined, and they are integrated with a nonlinear beam model for the full description of the dynamics of a free-flying flexible vehicle. Nonlinear time-marching solutions capture large wing excursions and wake roll-up, and the linearisation of the equations lends itself to a seamless, monolithic state-space assembly, particularly convenient for stability analysis and flight control system design. The numerical studies emphasise scenarios where the Unsteady Vortex-Lattice Method can provide an advantage over other state-of-the-art approaches. Examples of this include unsteady aerodynamics in vehicles with coupled aeroelasticity and flight dynamics, and in lifting surfaces undergoing complex kinematics, large deformations, or in-plane motions. Geometric nonlinearities are shown to play an instrumental, and often counter-intuitive, role in the aircraft dynamics. The Unsteady Vortex-Lattice Method is unveiled as a remarkable tool that can successfully incorporate all those effects in the unsteady aerodynamics modelling.
|Additional Information:||NOTICE: this is the author’s version of a work that was accepted for publication in Progress in Aerospace Sciences. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Progress in Aerospace Sciences, 55, November 2012, DOI 10.1016/j.paerosci.2012.06.001|
|Uncontrolled Keywords:||Potential flow, Unsteady aerodynamics, Free-wake models, Aeroelasticity, Flight dynamics|
|Divisions:||Faculty of Engineering and Physical Sciences > Mechanical Engineering Sciences|
|Depositing User:||Symplectic Elements|
|Date Deposited:||20 Nov 2012 08:58|
|Last Modified:||23 Sep 2013 19:39|
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