Limit Cycle Oscillations of Delta Wing Models in Low Subsonic Flow

Tang, Deman; Henry, James K.; Dowell, Earl H.

doi:10.2514/2.627

Cited by 88 publications

(9 citation statements)

References 6 publications

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“…Theoretical and experimental studies of platelike and beamlike wings with geometric structural nonlinearity [21][22][23][24] have indeed confirmed the importance of understanding when structural geometric nonlinear effects become aeroelastically important and accounting for them.…”

Section: Introductionmentioning

confidence: 74%

Dynamic Aeroelasticity of Structurally Nonlinear Configurations Using Linear Modally Reduced Aerodynamic Generalized Forces

Demasi

Livne

2009

AIAA Journal

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Steady-state and time-domain methods are introduced for integrating commonly used frequency-domain unsteady aerodynamic modeling based on a modal approach with full-order finite element models for structures with geometric nonlinearities. The methods are aimed at airplane configurations in which geometric-stiffness effects are important but deformations are moderate, flow is attached, and linear unsteady aerodynamic modeling is adequate, such as joined-wing and strut-braced wings at small-to-moderate angles of attack or a low-aspect-ratio wing. The approach proposed in this paper is to use the full-order structural matrices to capture the nonlinear structural behavior and modally reduced aerodynamic matrices calculated by adopting a frequency-domain-based commercial code such as ZAERO or a doublet-lattice method or linearized modal-based generalized aerodynamic matrices generated by computational fluid dynamics codes.

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Section: Introductionmentioning

confidence: 74%

Dynamic Aeroelasticity of Structurally Nonlinear Configurations Using Linear Modally Reduced Aerodynamic Generalized Forces

Demasi

Livne

2009

AIAA Journal

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“…The oscillating VG model was found to maintain steady limit cycle flapping motions for tunnel speeds above the flutter onset speed of U Flutter = 90 ft/s (tolerance ± 5%), which is significantly higher than the predicted flutter onset by the simulation model at 67 ft/s. As noted in Tang, Dowell et al [10][11][12][13] , it is extremely difficult to obtain an accurate prediction of flutter onset speeds and with the level of approximation in this model the predicted and measured flutter onset speeds are judged to be in relatively good agreement. The frequency of oscillation was measured using a strobe light.…”

Section: B Dynamic Model Developmentmentioning

confidence: 88%

Flow-Driven Oscillating Vortex Generators for Control of Boundary Layer Separation

Quackenbush

Danilov

Whitehouse

2010

40th Fluid Dynamics Conference and Exhibit

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Active flow control can be effective in tailoring boundary layer dynamics, but concepts developed to date have typically imposed significant design penalties because of the power and hardware required. This paper discusses the development and demonstration of a family of self-excited Flow Driven Oscillating Vortex Generators (FDOVGs) which oscillate at frequencies where the induced vortical flows have length scales that are of the order of the scale of the aerodynamic surface. FDOVGs receive power from the mean flow to operate and generate large amplitude oscillations that are useful for controlling boundary layer dynamics. This project entailed sequential concept development, analysis, design, fabrication, and testing of candidate FDOVG devices. Experimental activity included both studies of stand-alone FDOVGs as well as integrated tests of FDOVG arrays on lifting wings. Results clearly demonstrated the ability of these arrays to effect considerable improvements to attached flow with zero input power. In addition, several candidate mechanisms for deploying FDOVGs were developed, potentially enabling these improvements while also permitting device retraction, and, hence, yielding negligible cruise drag penalty. The demonstrations in hand are the first step in the development of micro-as well as macro-scale FDOVG devices with applications on micro air vehicles, UAVs, subsonic transports, and road vehicles. Nomenclature

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“…Following our early flutter model tests [5][6][7][8][9][10], in the present paper, a fuselage that is free to roll is designed, but the vertical rigid-body translation (plunge) and rotation (pitch) of the fuselage are constrained. The full-span wing is a cropped delta-wing plate for simplicity.…”

Section: Introductionmentioning

confidence: 99%

“…In our flutter/limit-cycle oscillation (LCO) model subsonic tests at Duke University for a low-aspect-ratio wing [5], wing-store combination [6], folding wing [7], all-movable horizontal tail [8], and a high-aspect-ratio wing aeroelastic model [9] all are cantilevered at the wing root. These are suitable for studying computational and experimental correlation for linear and nonlinear aeroelastic response.…”

Section: Introductionmentioning

confidence: 99%

Effects of a Free-to-Roll Fuselage on Wing Flutter: Theory and Experiment

Tang

Dowell

2014

AIAA Journal

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A theoretical study of a wing-fuselage combination with a rigid-body roll degree of freedom for the fuselage and elastic modes for the wing is presented along with a companion wind-tunnel test. The full-span wing dynamics are modeled using a linear-plate wing structure theory. A component modal analysis is used to derive the full structural equations of motion for the wing-fuselage combination system. A three-dimensional time-domain vortex-lattice aerodynamic model is also used to investigate flutter of the linear aeroelastic system. The experimentally observed flutter mode is antisymmetric, although theory suggests that the symmetric-mode flutter velocity is only modestly higher than that for the antisymmetric modes. Correlation between theory and experiment for flutter velocity and frequency is good. The experimentally observed postflutter response is a limit-cycle oscillation, and this is worthy of further study using an appropriate nonlinear theory. Nomenclature A, B = vortex-lattice aerodynamic coefficient matrices c = wing chord (including the leading and trailing control surface chords) f s , f as = symmetric and asymmetric natural frequencies J f , J w = fuselage and wing rolling inertias, respectively L = wingspan km, kn = numbers of vortex elements on wing in x− directions, respectively kmm = total number of vortices on both the wing and wake in the x−, y− direction m = mass per wing plate area m b = swinging pendulum mass m k = generalized mass of wing associated with the kth eigenmode q k = generalized coordinate of wing associated with the kth eigenmode R x , R y , R z = rotation angles r f = radius of the slender body (fuselage) T = transfer matrix from the downwash on the local vortex-lattice mesh on the wing to the global vortex-lattice mesh t = time U = airspeed W = downwash of wing w = out-of-plane displacement of wing x, y = streamwise and spanwise coordinates x ja , x jb = x positions of the two jth trailing vortex segments y ja , y jb = y positions of the two jth trailing vortex segments β = rolling angle Γ = vortex strength Δp = pressure distribution on the wing Δt = Δx∕U, time step ψx; y k = transverse natural mode of wing associated with the kth eigenmode ω b = natural frequency of a swinging pendulum ω k = natural frequency of wing associated with the kth eigenmode · = d·∕dt

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Limit Cycle Oscillations of Delta Wing Models in Low Subsonic Flow

Cited by 88 publications

References 6 publications

Dynamic Aeroelasticity of Structurally Nonlinear Configurations Using Linear Modally Reduced Aerodynamic Generalized Forces

Dynamic Aeroelasticity of Structurally Nonlinear Configurations Using Linear Modally Reduced Aerodynamic Generalized Forces

Flow-Driven Oscillating Vortex Generators for Control of Boundary Layer Separation

Effects of a Free-to-Roll Fuselage on Wing Flutter: Theory and Experiment

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