A Computional Investigation into the Use of Response Functions for Aerodynamic Loads Modeling

Ghoreyshi, Mehdi; Jirasek, Adam; Cummings, Russell M.; Post, Martiqua; Bergeron, Keith; Decker, Robert

doi:10.2514/6.2011-3518

Cited by 14 publications

(31 citation statements)

References 43 publications

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“…Such a rapid motion induces a special mechanism of flow separation and vortical flows that temporarily enhance the lift and decrease pitching moment [24,5]. Similar aerodynamic features also occur when a vehicle impulsively starts from rest, resulting in a sudden jump in aerodynamic loads [18]. Fig.…”

Section: Resultsmentioning

confidence: 74%

“…The time domain models are based on the state space representation by matching time histories of measured data. Some examples of time domain ROMs include the unit sample response [15,57,49,18], Volterra theory [56,55,54,9], Radial Basis Functions (RBF) [29,19,7] and state-space modeling [20,32]. In this paper, the mathematical model of indicial functions, Radial Basis Functions, and state-space method are presented.…”

Section: Reduced-order Aerodynamic Modelsmentioning

confidence: 99%

“…Singh and Baeder [57] used a surface transpiration approach to directly calculate the angle of attack indicial response using CFD. Ghoreyshi et al [18] also described an approach based on a grid motion technique for CFD-type calculation of linear and nonlinear indicial functions with respect to angle of attack and pitch rate.…”

Section: Indicial Functionsmentioning

confidence: 99%

“…Cobalt, the flow solver used, uses an arbitrary Lagrangian-Eulerian formulation and hence allows all translational and rotational degrees of freedom [18]. The code can simulate both free and specified six degree of freedom (6DoF) motions.…”

Section: Indicial Functionsmentioning

confidence: 99%

“…The nonlinear and unsteady aerodynamics can be viewed as a multi-input/multi-output dynamic system with a mathematical model in state space given by an ordinary differential equatioṅ (18) and an output equation as: (19) with given initial condition x = x 0 , for t = t 0 and…”

Section: Radial Basis Functionsmentioning

confidence: 99%

See 4 more Smart Citations

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: Resultsmentioning

confidence: 74%

Section: Reduced-order Aerodynamic Modelsmentioning

confidence: 99%

Section: Indicial Functionsmentioning

confidence: 99%

Section: Indicial Functionsmentioning

confidence: 99%

Section: Radial Basis Functionsmentioning

confidence: 99%

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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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Improved methodologies for the design of maneuver for stability and control simulations

Jirasek

Jeans

Martenson

et al. 2013

Aerospace Science and Technology

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Reduced order unsteady aerodynamic modeling for stability and control analysis using computational fluid dynamics

Ghoreyshi

Jirasek

Cummings

2014

Progress in Aerospace Sciences

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126

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, "Reduced order unsteady aerodynamic modeling for stability and control analysis using computational fluid dynamics" (2014 Contents ABSTRACTRecent advances and challenges in the generation of reduced order aerodynamic models using computational fluid dynamics are presented. The models reviewed are those that can be used for aircraft stability and control analysis and include linear and nonlinear indicial response methods, Volterra theory, radial basis functions, and a surrogate-based recurrence framework. The challenges associated with identification of unknowns for each of the reduced order methods are addressed. A range of test cases, from airfoils to full aircraft, have been used to evaluate and validate the reduced order methods. The motions have different amplitudes and reduced frequencies and could start from different flight conditions including those in the transonic speed range. Overall, these reduced order models help to produce accurate predictions for a wide range of motions, but with the advantage that model predictions require orders of magnitude less time to evaluate once the model is created.Published by Elsevier Ltd.

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A Computional Investigation into the Use of Response Functions for Aerodynamic Loads Modeling

Cited by 14 publications

References 43 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

Improved methodologies for the design of maneuver for stability and control simulations

Reduced order unsteady aerodynamic modeling for stability and control analysis using computational fluid dynamics

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