Frequency domain unsteady transonic aerodynamics for flutter and limit cycle oscillation prediction

Greco, Paulo; Lan, C. E.

doi:10.1590/s1678-58782010000500002

Cited by 5 publications

(8 citation statements)

References 8 publications

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“…Lan and his coworkers (Greco et al [17,18] and Hwang and Lan [26]) have used a single term in such a Fourier expansion and investigated the nonlinear potential-flow model in a series of interesting papers. Of course for sufficiently small amplitudes of airfoil or wing motion (and therefore fluid motion), a single-term approximation may suffice.…”

Section: Harmonic Balance Methodsmentioning

confidence: 99%

“…More recently, Hall and his coworkers (2000) have considered multiple harmonic terms in the Fourier series and developed computationally efficient methods for extracting the nonlinear solution to the Euler equations. Lan and his coworkers (Greco et al [17,18] and Hwang and Lan [26]) have applied his method to airfoils and wings, while Hall developed his methodology for turbomachinery applications to cascades of airfoils. Hall et al [19] have shown that a few harmonics are normally sufficient to describe the flow field accurately, even for rather large airfoil and fluid motions.…”

Section: Harmonic Balance Methodsmentioning

confidence: 99%

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Modeling of Fluid-Structure Interaction

Dowell

Hall

2021

A Modern Course in Aeroelasticity

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Modeling of aerodynamic forces has now moved beyond the classical potential flow theory at least in the research community and to some degree in engineering practice. These more sophisticated fluid models are based upon the Euler or Navier-Stokes equations and require substantial computer resources. This has led to the search for reduced order models that retain the higher physical fidelity of such flow models while still permitting computationally feasible solutions as described in this chapter.In the course of preparing this chapter, a bibliography of over 500 references was prepared and is available from the authors in electronic form upon request.

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Section: Harmonic Balance Methodsmentioning

confidence: 99%

Section: Harmonic Balance Methodsmentioning

confidence: 99%

Modeling of Fluid-Structure Interaction

Dowell

Hall

2021

A Modern Course in Aeroelasticity

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“…The second modification involves a procedure, which we have referred to as the shock jump correction procedure (Ly and Gear (2) ), that allows one to include the shock wave motion effects by correcting the solution values behind the shock wave, such that the time-linearised form of the shock jump condition will be satisfied. For the past three decades, time-linearised equations were solved in the frequency domain by numerous researchers, including the earliest attempt by Traci et al (7,8) , followed by Schippers and Hounjet (9) , Hounjet (10) , and most recently by Greco et al (11) , utilising a variety of computational methods of different levels of complexity, where the shock wave is assumed stationary throughout the time of the aerofoil motion. In general, their results compared reasonably with the experimental data, except in the regions where shock wave motion is anticipated.…”

Section: Introductionmentioning

confidence: 99%

Time-linearised transonic computations including entropy, vorticity and shock wave motion effects

Nakamichi²

2003

Aeronaut. j.

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The effect of small perturbations on steady nonlinear transonic small disturbance flowfields, in the context of two-dimensional flows governed by the general-frequency transonic small disturbance equation with nonreflecting far-field boundary conditions, is investigated. This paper presents a time-linearised time-domain solution method that includes effects due to the shock-generated entropy and vorticity and shock wave motions. The solution procedure correctly accounts for the small-amplitude shock wave motion due to small unsteady changes in the aerofoil boundary conditions, and correctly models a flowfield with embedded strong shock waves. Steady and first harmonic pressure distributions for the NACA 0003 aerofoil with a harmonically oscillating flap, and NACA 0012 aerofoil undergoing a sinusoidal pitching oscillation, are predicted and compared with the Euler results.

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“…To ease the investigations into the bifurcation behaviour several alternatives to time domain methods are used. One of these methods is the aeroelastic harmonic balance (HB) method as first described by Greco et al [7] and Thomas et al [8]. In this aeroelastic HB method, a HB flow solver, in which the governing flow equations are transferred into the frequency domain by Fourier transform, is used.…”

mentioning

confidence: 99%

“…The aerodynamic forces are obtained from the HB flow solver at each iteration. Greco et al [7] used to the frequency-domain transonic small disturbance equations to determine the aerodynamic forces. A Computational Fluid Dynamics (CFD)-based HB method solving the Euler equations was used by Hall et al [9].…”

mentioning

confidence: 99%

Prediction of Aeroelastic Limit-Cycle Oscillations Based on Harmonic Forced-Motion Oscillations

2017

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Aeroelastic limit-cycle oscillations (LCO) due to aerodynamic non-linearities are usually investigated using coupled fluid-structure interaction simulations in the time domain. These simulations are computationally expensive, especially if a large number of LCO solutions must be computed to study the Hopf bifurcation behaviour in the immediate surrounding of the flutter point. To facilitate such bifurcation parameter studies an adaptation of the well-known p-k flutter analysis method is proposed in this paper. In this frequency domain method, the first harmonic of the motion-induced unsteady aerodynamic forces is no longer assumed to be solely determined by constantcoefficient frequency response functions. Instead, the non-linear dependence on the oscillation amplitudes and the phase angle between the input degrees of freedom is additionally taken into account. Therefore, the first harmonic Fourier components of the aerodynamic forces are sampled and interpolated in advance. The LCO solution is then found iteratively. The proposed amplitude-dependent p-k method (ADePK) is applied to a classic two-degree-of-freedom spring-mounted airfoil system where the non-linear aerodynamic forces are computed from Euler simulations. Fluid-structure

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Frequency domain unsteady transonic aerodynamics for flutter and limit cycle oscillation prediction

Cited by 5 publications

References 8 publications

Modeling of Fluid-Structure Interaction

Modeling of Fluid-Structure Interaction

Time-linearised transonic computations including entropy, vorticity and shock wave motion effects

Prediction of Aeroelastic Limit-Cycle Oscillations Based on Harmonic Forced-Motion Oscillations

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