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On the effects of vertical offset and core structure in streamwise-oriented vortex–wing interactions

Published online by Cambridge University Press:  21 June 2016

C. J. Barnes*
Affiliation:
Air Force Research Laboratory, Wright-Patterson AFB, OH 45433, USA
M. R. Visbal
Affiliation:
Air Force Research Laboratory, Wright-Patterson AFB, OH 45433, USA
P. G. Huang
Affiliation:
Department of Mechanical and Materials Engineering, Wright State University, Dayton, OH 45435, USA
*
Email address for correspondence: caleb.barnes.1@us.af.mil

Abstract

This article explores the three-dimensional flow structure of a streamwise-oriented vortex incident on a finite aspect-ratio wing. The vertical positioning of the incident vortex relative to the wing is shown to have a significant impact on the unsteady flow structure. A direct impingement of the streamwise vortex produces a spiralling instability in the vortex just upstream of the leading edge, reminiscent of the helical instability modes of a Batchelor vortex. A small negative vertical offset develops a more pronounced instability while a positive vertical offset removes the instability altogether. These differences in vertical position are a consequence of the upstream influence of pressure gradients provided by the wing. Direct impingement or a negative vertical offset subject the vortex to an adverse pressure gradient that leads to a reduced axial velocity and diminished swirl conducive to hydrodynamic instability. Conversely, a positive vertical offset removes instability by placing the streamwise vortex in line with a favourable pressure gradient, thereby enhancing swirl and inhibiting the growth of unstable modes. In every case, the helical instability only occurs when the properties of the incident vortex fall within the instability threshold predicted by linear stability theory. The influence of pressure gradients associated with separation and stall downstream also have the potential to introduce suction-side instabilities for a positive vertical offset. The influence of the wing is more severe for larger vortices and diminishes with vortex size due to weaker interaction and increased viscous stability. Helical instability is not the only possible outcome in a direct impingement. Jet-like vortices and a higher swirl ratio in wake-like vortices can retain stability upon impact, resulting in the laminar vortex splitting over either side of the wing.

Type
Papers
Copyright
© Cambridge University Press 2016. This is a work of the U.S. Government and is not subject to copyright protection in the United States. 

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References

Alpert, P. 1981 Implicit filtering in conjunction with explicit filtering. J. Comput. Phys. 44, 212219.Google Scholar
Barnes, C. J., Visbal, M. R. & Gordnier, R. E.2014a Investigation of aeroelastic effects in streamwise-oriented vortex/wing interactions. 52nd AIAA Aerospace Sciences Meeting, 13–17 January 2014, National Harbor, MD, USA, paper number 2014-1281. AIAA.Google Scholar
Barnes, C. J., Visbal, M. R. & Gordnier, R. E. 2015 Analysis of streamwise-oriented vortex interactions for two wings in close proximity. Phys. Fluids 27, 015103.Google Scholar
Barnes, C. J., Visbal, M. R. & Huang, P. G.2014b Numerical simulations of streamwise-oriented vortex/flexible wing interactions. 44th AIAA Fluid Dynamics Conference, 16–20 June 2014, Atlanta, GA, USA, paper number 2014-2313. AIAA.CrossRefGoogle Scholar
Batchelor, G. 1964 Axial flow in trailing line vortices. J. Fluid Mech. 20 (4), 645658.CrossRefGoogle Scholar
Beam, R. & Warming, R. 1978 An implicit factored scheme for the compressible Navier–Stokes equations. AIAA J. 16, 393402.Google Scholar
Bhagwat, M. J., Caradonna, F. X. & Ramasamy, M. 2015 Wing–vortex interaction: unraveling the flowfield of a hovering rotor. Exp. Fluids 56 (1), 117.CrossRefGoogle Scholar
Blake, W. B. & Gingras, D. R. 2004 Comparison of predicted and measured formation flight. J. Aircraft 41 (2), 201207.CrossRefGoogle Scholar
Choi, H. & Moin, P. 1994 Effects of the computational time step on numerical solutions of turbulent flow. J. Comput. Phys. 113 (1), 14.CrossRefGoogle Scholar
Gaitonde, D. & Visbal, M.1999 Further development of a Navier–Stokes solution procedure based on higher-order formulas. 37th AIAA Aerospace Sciences Meeting & Exhibit, 11–14 January 1999, Reno, NV, USA, paper number 1999-0557. AIAA.CrossRefGoogle Scholar
Gaitonde, D. V. & Visbal, M. R.1998 High-order schemes for Navier–Stokes equations: algorithm and implementation into FDL3DI. Tech. Rep. AFRL-VI-WP-TR-1998-3060, Air Force Research Laboratory, Wright-Patterson AFB.Google Scholar
Garmann, D. J. & Visbal, M. R.2014 Unsteady interactions of a wandering streamwise-oriented vortex with a wing. 32nd AIAA Applied Aerodynamics Conference, 16–20 June 2014, Atlanta, GA, USA, paper number 2014-2105. AIAA.CrossRefGoogle Scholar
Garmann, D. J. & Visbal, M. R. 2015a Interaction of a streamwise-oriented vortex with a wing. J. Fluid Mech. 767, 782810.CrossRefGoogle Scholar
Garmann, D. J. & Visbal, M. R.2015b Streamwise-oriented vortex interactions with a NACA0012 wing. 53rd AIAA Aerospace Sciences Meeting, 5–9 January 2015, Kissimmee, FL, USA, paper number 2015-1066. AIAA.Google Scholar
Garmann, D. J., Visbal, M. R. & Orkwis, P. D. 2012 Comparative study of implicit and subgrid-scale model large-eddy simulation techniques for low-Reynolds number airfoil applications. Intl J. Numer. Meth. Fluids 71 (12), 15461565.Google Scholar
Georgiadis, N. J., Rizzetta, D. P. & Fureby, C. 2010 Large-eddy simulation: current capabilities, recommended practices, and future research. AIAA J. 48 (8), 17721784.CrossRefGoogle Scholar
Gordnier, R. & Visbal, M. 1999 Numerical simulation of the impingement of a streamwise vortex on a plate. Intl J. Comput. Fluid Dyn. 12 (1), 4966.Google Scholar
Gursul, I. & Xie, W. 2001 Interaction of vortex breakdown with an oscillating fin. AIAA J. 39 (3), 438446.Google Scholar
Ham, N. D. 1975 Some conclusions from an investigation of blade–vortex interaction. J. Am. Helicopter Soc. 20 (4), 2631.Google Scholar
Hummel, D. 1995 Formation flight as an energy-saving mechanism. Israel J. Zool. 41, 261278.Google Scholar
Inasawa, A., Mori, F. & Asai, M. 2012 Detailed observations of interactions of wingtip vortices in close-formation flight. J. Aircraft 49 (1), 206213.CrossRefGoogle Scholar
Jacquin, L. & Pantano, C. 2002 On the persistence of trailing vortices. J. Fluid Mech. 471, 159168.CrossRefGoogle Scholar
Jameson, A., Schmidt, W. & Turkel, E.1981 Numerical solutions of the Euler equations by finite volume methods using Runge–Kutta time stepping schemes. 14th AIAA Fluid and Plasma Dynamics Conference, 23–25 June 1981, Palo Alto, CA, USA, paper number 1981-1259. AIAA.CrossRefGoogle Scholar
Jeong, J. & Hussain, F. 1995 On the identification of a vortex. J. Fluid Mech. 285, 6994.CrossRefGoogle Scholar
Kandil, O. A., Sheta, E. F. & Massey, S. J.1995 Buffet responses of a vertical tail in vortex breakdown flows. 20th Atmospheric Flight Mechanics Conference, 7–10 August 1995, Baltimore, MA, USA, paper number 1995-3464. AIAA.Google Scholar
Kless, J. E., Aftosmis, M. J., Ning, S. A. & Nemec, M. 2013 Inviscid analysis of extended-formation flight. AIAA J. 51 (7), 17031715.Google Scholar
Lambert, C. & Gursul, I. 2004 Characteristics of fin buffeting over delta wings. J. Fluids Struct. 19, 307319.CrossRefGoogle Scholar
Leibovich, S. 1978 The structure of vortex breakdown. Annu. Rev. Fluid Mech. 10, 221246.CrossRefGoogle Scholar
Leibovich, S. & Stewartson, K. 1983 A sufficient condition for the instability of columnar vortices. J. Fluid Mech. 126, 335356.Google Scholar
Lele, S. 1992 Compact finite difference schemes with spectral-like resolution. J. Comput. Phys. 103, 1642.Google Scholar
Mathew, J., Lechner, R., Foysi, H., Sesterhenn, J. & Friedrich, R. 2003 An explicit filtering method for large eddy simulation of compressible flows. Phys. Fluids 15 (8), 22792289.Google Scholar
Mayori, A. & Rockwell, D. 1994 Interaction of a streamwise vortex with a thin plate: a source of turbulent buffeting. AIAA J. 32 (10), 20222029.Google Scholar
McAlister, K. W. & Tung, C.1984 Airfoil interaction with an impinging vortex. NASA Tech. Rep. 2273.Google Scholar
Ning, S. A.2011 Aircraft drag reduction through extended formation flight. PhD thesis, Department of Aeronautics and Astronautics, Stanford University, Stanford, CA.Google Scholar
Pulliam, T. 1986 Artificial dissipation models for the Euler equations. AIAA J. 24 (12), 19311940.Google Scholar
Pulliam, T. & Chaussee, D. 1981 A diagonal form of an implicit approximate-factorization algorithm. J. Comput. Phys. 17 (10), 347363.Google Scholar
Rai, M. M. 1989 Three-dimensional Navier–Stokes simulations of turbine rotor–stator interaction. Part i: methodology. J. Propul. 5 (3), 305311.Google Scholar
Rai, M. M. & Chakravarthy, S. R. 1986 An implicit form for the Osher upwind scheme. AIAA J. 24 (5), 735743.CrossRefGoogle Scholar
Rockwell, D. 1998 Vortex–body interactions. Annu. Rev. Fluid Mech. 30, 199229.Google Scholar
Saffman, P. G. 1992 Vortex Dynamics. Cambridge University Press.Google Scholar
Sarpkaya, T. 1974 Effect of the adverse pressure gradient on vortex breakdown. AIAA J. 12 (5), 602607.Google Scholar
Slotnick, J. P., Clark, R. W., Friedmann, D. M., Yadlin, Y., Yeh, D. T., Carr, J. E., Czech, M. J. & Bieniawski, S. W.2014 Computational aerodynamic analysis for the formation flight for aerodynamic benefit program. 52nd AIAA Aerospace Sciences Meeting, 13-17 January 2014, National Harbor, MA, USA, paper number 2014-1458. AIAA.CrossRefGoogle Scholar
Stolz, S. & Adams, N. 1999 An approximate deconvolution procedure for large-eddy simulation. Phys. Fluids 11 (7), 16991701.Google Scholar
Visbal, M. & Gaitonde, D. 2001 Very high-order spatially implicit schemes for computational acoustics on curvilinear meshes. J. Comput. Acoust. 9 (4), 12591286.CrossRefGoogle Scholar
Visbal, M. R. 1994 Onset of vortex breakdown about a pitching delta wing. AIAA J. 38 (8), 15681575.Google Scholar
Visbal, M. R. & Gaitonde, D. V. 1999 High-order-accurate methods for complex unsteady subsonic flows. AIAA J. 37 (10), 12311239.Google Scholar
Visbal, M. R., Morgan, P. E. & Rizzetta, D. P.2003 An implicit LES approach based on high-order compact differencing and filtering schemes. 16th AIAA Computational Fluid Dynamics Conference, 23–26 June 2003, Orlando, FL, USA, paper number 2003-4098. AIAA.Google Scholar
Visbal, M. R. & Rizzetta, D. P. 2002 Large-eddy simulation on curvilinear grids using compact differencing and filtering schemes. Trans. ASME J. Fluids Engng 124, 836847.Google Scholar
Wittmer, K. S. & Devenport, W. J. 1999 Effects of perpendicular blade–vortex interaction. Part 1: turbulence structure and development. AIAA J. 37 (7), 805812.Google Scholar
Wolfe, S., Canbazoglu, S., Lin, J. C. & Rockwell, D. 1995 Buffeting of fins: assessment of surface pressure loading. AIAA J. 33, 22322235.CrossRefGoogle Scholar
Wu, J., Ma, H. & Zhou, M. 2006 Vorticity and Vortex Dynamics. Springer.Google Scholar
Zanotti, A., Ermacora, M., Campanardi, G. & Gibertini, G. 2014 Stereo particle image velocimetry measurements of perpendicular blade–vortex interaction over an oscillating airfoil. Exp. Fluids 55 (9), 113.CrossRefGoogle Scholar

Barnes et al. supplementary movie

Top view of instantaneous flow structure using an iso-surface of Q-criterion (Q=15) for several vertical positions. A dashed line roughly locates the onset of instability.

Download Barnes et al. supplementary movie(Video)
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