A Numerical Study of a Rotor Induced Flow Based on a Finite-State Dynamic Wake Model.

L. G. A. Ferreira, C. C. Pagani Júnior, E. M. Gennaro, C. De Marqui Junior

Abstract


A Helicopter rotor undergoes unsteady aerodynamic loads ruled by the aeroelastic coupling between the elastic blades and the dynamic wake induced by rotary wings. Modeling the dynamic interaction between the structural and aerodynamic fields is a key point to understand aeroelastic phenomena associated with rotor stability, flow induced vibration and noise generation, among others. In this study, we address the Generalized Dynamic Wake Model, which describes the inflow velocity field at the rotor disk as a superposition  of a finite number of induced flow states. It is a mature model that has been validated based on experimental data and numerically investigated from an eigenvalue problem formulation, whose eigenvalues and eigenvectors provide a deeper insight on the dynamic wake behavior. The paper extends the results presented in the literature to date in order to support physical interpretation of inflow states drawn from the finite-state wake model for flight conditions varying from hover to edgewise flight. The discussion of the wake model mathematical formulation is also oriented towards practical engineering applications to fill a gap in the literature.

Keywords


Unsteady wake; eigen-analysis; inflow states.

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References


D. M. Pitt and D. A. Peters, "Theoretical Prediction of Dynamic-Inflow Derivatives," Vertica, vol. 5, no. 1, pp. 21-34, 1981.

C. Garcia-Duffy, M. C. Hsieh, and D. A. Peters, “A Complete, Nonlinear Induced Flow Theory For Rotors In Incompressible Flow,” in 11th Pan-American Congress of Applied Mechanics, January 04-08, 2010, Foz do Iguaçu, PR, Brazil, 2009.

D. A. Peters, C. J. He, and A. A. Su, "Closed-form, Finite-state model for the unsteady aerodynamics of rotors," Computational Mechanics, 1988.

C. He, Development and application of a generalized dynamic wake theory for lifting rotors. PhD thesis, Georgia Institute of Technology, Georgia Institute of Technology, Georgia, 1989.

D. H. Hodges and G. A. Pierce, Introduction to Structural Dynamics and Aeroelasticity. Cambridge Aerospace Series, Cambridge University Press, 2 ed., 2011.

J. Morillo and D. A. Peters, "Velocity Field above a Rotor Disk by a New Dynamic Inflow Model," Journal of Aircraft, vol. 39, no. 5, pp. 731-738, 2002.

X. Shang, D. H. Hodges, and D. A. Peters, "Aeroelastic stability of composite hingeless rotors in hover with Finite-state unsteady aerodynamics," Journal of the American Helicopter Society, vol. 44, no. 3, pp. 206-221, 1999.

Y. R. WANG, The Effect of wake dynamics on rotor eigenvalues in forward flight. PhD thesis, Georgia Institute of Technology, Georgia Institute of Technology, Georgia, 1992.

D. Andrade, Application of Finite-state inflow to flap-lag-torsion damping in hover. PhD thesis, Georgia Institute of Technology, Georgia Institute of Technology, Georgia, 1992.

D. A. Peters and W. Cao, "Off-rotor induced flow by a finite-state wake model," in 37th AIAA SDM Conference, Salt Lake City, April 15-17, 1996.

D. A. Peters, A. Hsieh, and C. Garcia-Duffy, "A complete finite-state inflow theory from the potential flow equations," in Given as the Keynote Lecture and included in the Proceedings of the 3rd International Basic Research Conference on Rotorcraft Technology, Nanjing, China, Oct. 14-16, 2009.

Z. Fei, A Rigorous solution for finite-state inflow throughout the flowfield. PhD thesis, Georgia Institute of Technology, Washington University in St. Louis, 2013.




DOI: https://doi.org/10.5540/tcam.2021.022.02.00307

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Trends in Computational and Applied Mathematics

A publication of the Brazilian Society of Applied and Computational Mathematics (SBMAC)

 

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