A Numerical Study of a Rotor Induced Flow Based on a Finite-State Dynamic Wake Model.
DOI:
https://doi.org/10.5540/tcam.2021.022.02.00307Keywords:
Unsteady wake, eigen-analysis, inflow states.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.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.
Downloads
Published
How to Cite
Issue
Section
License
Authors who publish in this journal agree to the following terms:
Authors retain copyright and grant the journal the right of first publication, with the work simultaneously licensed under the Creative Commons Attribution License that allows the sharing of the work with acknowledgment of authorship and initial publication in this journal.
Authors are authorized to assume additional contracts separately, for non-exclusive distribution of the version of the work published in this journal (eg, publish in an institutional repository or as a book chapter), with acknowledgment of authorship and initial publication in this journal.
Authors are allowed and encouraged to publish and distribute their work online (eg, in institutional repositories or on their personal page) at any point before or during the editorial process, as this can generate productive changes as well as increase impact and the citation of the published work (See The effect of open access).
This is an open access journal which means that all content is freely available without charge to the user or his/her institution. Users are allowed to read, download, copy, distribute, print, search, or link to the full texts of the articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the
author. This is in accordance with the BOAI definition of open access
Intellectual Property
All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License under attribution BY.