Physics-Based Low-Order Model for Transonic Flutter Prediction

Opgenoord, Max M. J.; Drela, Mark; Willcox, Karen

doi:10.2514/1.j056710

Cited by 25 publications

(17 citation statements)

References 41 publications

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“…In addition to the classical bending-torsion flutter, transonic aeroelasticity also exhibits many unique phenomena [1][2][3]. For example, the sweptback wing experiences a drop of the flutter boundary in the transonic regime, called the transonic dip phenomenon [4][5][6][7]. There is a relatively large discrepancy between the computational and experimental flutter boundaries when the Mach numbers are near the transonic dip [8].…”

Section: Introductionmentioning

confidence: 99%

Transonic aeroelasticity: A new perspective from the fluid mode

Gao

Zhang

2020

Progress in Aerospace Sciences

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Within the transonic regime, the aeroelastic problems exhibit many unique characteristics compared with subsonic and supersonic cases. Although a lot of research has been carried out in this field, the underlying mechanisms of these complex phenomena are not clearly understood yet, resulting in a challenge in the design and use of modern aircraft. This review summarizes the recent investigations on nonclassical transonic aeroelastic problems, including transonic buzz, reduction of transonic buffet onset, transonic buffeting response and frequency lock-in phenomenon in transonic buffet flow. After introducing the research methods in unsteady aerodynamics and aeroelastic problems, the dynamical characteristics as well as the physical mechanisms of these phenomena are discussed from the perspective of the fluid mode. In the framework of the ROM (reduced order model) -based model, the dominant fluid mode (or the eigenvalue) and its coupling process with the structural model can be clearly captured. The flow nonlinearity was believed to be the cause of the complexity of transonic aeroelasticity. In fact, this review indicates that the complexity lies in the decrease of the flow stability in the transonic regime. In this condition, the fluid mode becomes a principal part of the coupling process, which results in the instability of the fluid mode itself or the structural mode, and thus, it is the root cause of different transonic aeroelastic phenomena.

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Section: Introductionmentioning

confidence: 99%

Transonic aeroelasticity: A new perspective from the fluid mode

Gao

Zhang

2020

Progress in Aerospace Sciences

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“…The complete aeroelastic tailoring approach can be summarized as follows. This work uses a previously-developed physics-based low-order model for transonic flutter [31,32]. The first step, therefore, is to calibrate the aerodynamic coefficients of that model using 2D unsteady Euler simulations for the airfoil family used in the wing design.…”

Section: Iia Aeroelastic Tailoring Approachmentioning

confidence: 99%

“…At transonic Mach numbers, Theodorsen theory with compressibility corrections is no longer accurate. Instead, we employ a physics-based low-order model for transonic flutter [31,32]. This section briefly summarizes the physics-based model's formulation; for more details, see Ref.…”

Section: Iib Low-order Aerodynamic Modelmentioning

confidence: 99%

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Design Methodology for Aeroelastic Tailoring of Additively Manufactured Lattice Structures Using Low-Order Methods

Opgenoord

Willcox

2019

AIAA Journal

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Additively-manufactured wings can be aeroelastically tailored, which offers potential for increased air vehicle efficiency via lighter structures. This paper develops a methodology to design aeroelastically-tailored wings using additively-manufactured lattice structures. Adaptive meshing techniques are used to design the topology of the lattice to align with the load direction and the lattice is optimized to minimize the structural weight and to improve the flutter margin. To alleviate the computational effort of aeroelastically tailoring a structure, a low-order model for the dynamics of the lattice structure is developed. This structural low-order model is coupled to a previously-developed physics-based transonic flutter model to compute the aeroelastic behavior of wings with internal lattice structures. The structural low-order model is validated by comparing against the full-order structural dynamics model. Finally, the design methodology is applied to the design of an internal structure of an aircraft wing to increase that wing's flutter speed.

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“…The accuracy of the physics-based low-order model has already been demonstrated in Ref. [19]. Strip theory is an accepted method for the aerodynamic response of high-aspect-ratio wings [24,25] and thoroughly validated in the literature [30,31].…”

Section: Validation Of 3d Flutter Modelmentioning

confidence: 99%

Influence of Transonic Flutter on the Conceptual Design of Next-Generation Transport Aircraft

Opgenoord

Drela

Willcox

2018

2018 AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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Transonic aeroelasticity is an important consideration in the conceptual design of nextgeneration aircraft configurations. This paper develops a low-order physics-based flutter model for swept high-aspect-ratio wings. The approach builds upon a previously developed flutter model that uses the flowfield's lowest moments of vorticity and volume-source density perturbations as its states. The contribution of this paper is a new formulation of the model for swept high-aspect-ratio wings. The aerodynamic model is calibrated using off-line 2D unsteady transonic CFD simulations. Combining that aerodynamic model with a beam model results in a low-dimensional overall aeroelastic system. The low computational cost of the model permits its incorporation in a conceptual design tool for next-generation transport aircraft. The model's capabilities are demonstrated by finding transonic flutter boundaries for different clamped wing configurations, and investigating the influence of transonic flutter on the planform design of next-generation transport aircraft.

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Physics-Based Low-Order Model for Transonic Flutter Prediction

Cited by 25 publications

References 41 publications

Transonic aeroelasticity: A new perspective from the fluid mode

Transonic aeroelasticity: A new perspective from the fluid mode

Design Methodology for Aeroelastic Tailoring of Additively Manufactured Lattice Structures Using Low-Order Methods

Influence of Transonic Flutter on the Conceptual Design of Next-Generation Transport Aircraft

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