Prediction of Flutter and LCO by an Euler Method on Non-moving Cartesian Grids with Boundary-Layer Corrections

Zhang, Zhichao; Yang, Sun; Liu, Feng; Schuster, David M.; Branch, Aeroelasticity

doi:10.2514/6.2005-833

Cited by 13 publications

(2 citation statements)

References 28 publications

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“…To investigate the unsteady transonic aerodynamic and aeroelastic behaviors of multi-airfoil systems with possible large amplitude body motions and shock excursions, the use of the Euler or Navier-Stokes solver on unstructured dynamic meshes is highly desir-able. Zhang et al [10] studied systematically the flutter prediction of a two-dimensional wing model using five different Euler and Navier-Stokes methods. The unsteady pressure wave, shock wave and vortex-shedding phenomena are discussed.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Aerodynamic Effects on Transonic Flap Buzz, Tail Flutter and Limit-Cycle Oscillations of Two-Dimensional Wing-Flap-Tail Configurations

Cheng

2009

J. mech.

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The transonic tail flutter and flap buzz under the wing-flap-tail configurations are analyzed utilizing a dynamic grid capability of unstructured Euler solver coupled with an appropriate aeroelastic solver. From the results, the presence of a forewing, either stationary or oscillating, has significant effect on the tail flutter characteristics. In particular, the tail motion may be in resonance with the oscillating wing before the onset of flutter, which is dangerous to the tail structure because of the large amplitude oscillations. Besides, a complicated aerodynamic and aeroelastic interference of the tail have been found due to the unsteady disturbance which is a strong variability of flow structure induced by the buzz of the flap. In the high transonic flow regime, the flap buzz with limit-cycle oscillations does occur, and the influence induced by the tail is not important. The increasing restoring force at the pivot where the flap joints with the wing will reduce the flap oscillations that improves the effect of the flap buzz.

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Section: Introductionmentioning

confidence: 99%

Nonlinear Aerodynamic Effects on Transonic Flap Buzz, Tail Flutter and Limit-Cycle Oscillations of Two-Dimensional Wing-Flap-Tail Configurations

Cheng

2009

J. mech.

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“…Several recent studies used CFD solutions to study either the shock-buet phenomenon (in which the airfoil itself does not oscillate [8,9,1116]) or the transonic aeroelastic problem, in which the airfoil is spring-suspended but there is no buet [17,18]. Recent studies by the authors [10,19,20] presented Navier-Stokes simulations of airfoil responses to prescribed motions (plunge, pitch, and trailing-edge ap rotation) about ow conditions that exhibit shockbuet.…”

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confidence: 99%

Aeroelastic Responses of Spring-suspended Airfoil Systems in Transonic Buffeting Flows

Raveh¹,

Dowell²

2012

53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

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Computer simulations are performed to determine the responses of a single DOF pitch airfoil system, as well as those of a two DOF pitch-and-heave system, in bueting ows. The bueting ow exhibits shock-wave oscillations of a unique frequency that occurs for some combinations of mean ow angle of attack and transonic Mach numbers. It was found that frequency lock-in may occur, depending on the relationship between the buet and structural frequencies. Following frequency lock-in the system response rapidly increases until reaching limit-cycle oscillations. Synchronization of the transonic aerodynamic buet phenomenon and the structural elastic modes provides a physical mechanism that may be responsible for some aircraft transonic LCO occurrences. It is distinctly dierent from a utter mechanism, leading to LCO, as discussed in the manuscript. Nomenclature a ∞ = speed of sound, m/s C L = airfoil lift coecient b = half chord length, m c = chord length, m f = frequency, Hz f = 2πf c/U ∞ = reduced frequencȳ f sb = 2πf c/U ∞ = shock-buet reduced frequency M ∞ = free-stream Mach number R ∞ = free-stream Reynolds number, based on chord t = physical time, s t = nondimensional time U ∞ = far-eld velocity, m/s Y + = dimensionless wall distance α ∞ = free-stream angle of attack, deg ∆C L = lift coecient peak-to-peak amplitude ∆t = nondimensional computational time step

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Insights on the unsteadiness and stall effects on the characteristics and responses of continuous wing-based systems
Yossri
¹
,
Bouma
²
,
Ayed
³

et al. 2021
Nonlinear Dyn
6
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1
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Prediction of Flutter and LCO by an Euler Method on Non-moving Cartesian Grids with Boundary-Layer Corrections

Cited by 13 publications

References 28 publications

Nonlinear Aerodynamic Effects on Transonic Flap Buzz, Tail Flutter and Limit-Cycle Oscillations of Two-Dimensional Wing-Flap-Tail Configurations

Nonlinear Aerodynamic Effects on Transonic Flap Buzz, Tail Flutter and Limit-Cycle Oscillations of Two-Dimensional Wing-Flap-Tail Configurations

Aeroelastic Responses of Spring-suspended Airfoil Systems in Transonic Buffeting Flows

Insights on the unsteadiness and stall effects on the characteristics and responses of continuous wing-based systems

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