Computation of Unsteady Transonic Flows by the Indicial Method

Ballhaus, W. F.; Goorjian, Peter M.

doi:10.2514/3.60868

Cited by 195 publications

(34 citation statements)

References 3 publications

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“…The frequency domain models are obtained from matching transfer functions computed from the measured input-output data [27]. Examples of the frequency domain ROMs are the indicial response method [3,62,61] and a frequency-domain model based on Proper Orthogonal Decomposition (POD) [25,66]. The time domain models are based on the state space representation by matching time histories of measured data.…”

Section: Reduced-order Aerodynamic Modelsmentioning

confidence: 99%

Challenges in the aerodynamics modeling of an oscillating and translating airfoil at large incidence angles

Ghoreyshi

Cummings

2013

Aerospace Science and Technology

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The challenges in the modeling of the unsteady lift of a two-dimensional NACA 0012 airfoil oscillating and translating at large incidence angles are investigated in this paper. Forced oscillation motions with two reduced frequency values of 0.1 and 1.0 were used. The CFD results show that a hysteresis loop was developed in the lift variation with angle of attack; shapes of the loops change significantly with reduced frequency value. A dynamic stall vortex was identified in the pitching and plunging motions with k = 0.1.This vortex delays the onset of flow separation over the upper surface to a higher incidence than would occur in steady conditions. The unsteady lift of the very fast motion is enhanced significantly due to the formation of a compression wave on the lower surface and an expansion wave on the upper surface. The results show clear limitations of unsteady aerodynamic theories for modeling motions at high incidences. Also, the CFD solution of indicial functions show a large oscillation at angles of attack beyond the stall angle, but the predictions of a model based on Radial Basis Function matches CFD values quite well.

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Section: Reduced-order Aerodynamic Modelsmentioning

confidence: 99%

Challenges in the aerodynamics modeling of an oscillating and translating airfoil at large incidence angles

Ghoreyshi

Cummings

2013

Aerospace Science and Technology

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“…Alternatively,the estimatesmay be obtained from Fourier transformation of the response to a step change in a given mode of motion. 13 The harmonic oscillation technique is costly since calculationsmay be reauired for 5-10 reduced frequencies. In contrast,the indicial responseapproach can be inaccuratefor finite differencesolutions of Eq.…”

Section: Pulse Techniquementioning

confidence: 99%

An exploratory study of finite difference grids for transonic unsteady aerodynamics

Seidel

Bennett

Whitlow

1983

21st Aerospace Sciences Meeting

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“…Correct treatment of the changing type of PDE within the flow domain was a challenge to the CFD community until the early 70's, when Murman and Cole discovered a stable finite diffrence (FD) scheme for the steady Transonic Small Disturbance (TSD) equation [3,4]. Unsteady formulations were the next hurdle.…”

Section: Introductionmentioning

confidence: 99%

A Robust Solution Procedure for the Transonic Small-Disturbance Equation in Fluid-Structure Interactions

Opstal¹,

Hulshoff²,

Verhoosel

2011

TOAEJ

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Computation of Unsteady Transonic Flows by the Indicial Method

Cited by 195 publications

References 3 publications

Challenges in the aerodynamics modeling of an oscillating and translating airfoil at large incidence angles

Challenges in the aerodynamics modeling of an oscillating and translating airfoil at large incidence angles

An exploratory study of finite difference grids for transonic unsteady aerodynamics

A Robust Solution Procedure for the Transonic Small-Disturbance Equation in Fluid-Structure Interactions

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