Data-based aerodynamic modeling using nonlinear indicial theory

Reisenthel, Patrick; Bettencourt, Matthew Tyler

doi:10.2514/6.1999-763

Cited by 25 publications

(16 citation statements)

References 2 publications

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“…The indicial response functions are used as a fundamental approach to represent the unsteady aerodynamic loads. The mathematical models are detailed by Tobak et al [14,15], Reisenthel [23], and Reisenthel and Bettencourt [24]. The pitch moment is only considered in this paper because it is the more-difficult parameter to predict.…”

Section: Reduced-order Models Based On Indicial Functionsmentioning

confidence: 99%

“…Assuming that the indicial functions are known, the aerodynamic forces and moments induced in any maneuver can be estimated by using the well-known Duhamel superposition integral [22]. Tobak et al [14,15], Reisenthel [23], and Reisenthel and Bettencourt [24] detailed the superposition process for the modeling of unsteady lift and pitch moment from angle of attack and pitch rate indicial functions. Ghoreyshi and Cummings [25] extended this model to include lateral forces and moments as well.…”

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confidence: 99%

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Transonic Aerodynamic Load Modeling of X-31 Aircraft Pitching Motions

Ghoreyshi¹,

Cummings²,

Ronch³

et al. 2013

AIAA Journal

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The generation of reduced-order models for computing the unsteady and nonlinear aerodynamic loads on an aircraft from pitching motions in the transonic speed range is described. The models considered are based on Duhamel's superposition integral using indicial (step) response functions, Volterra theory using nonlinear kernels, radial basis functions, and a surrogate-based recurrence framework, both using time-history simulations of a training maneuver(s). Results are reported for the X-31 configuration with a sharp leading-edge cranked delta wing geometry, including canard/wing vortex interactions. The validity of the various models studied was assessed by comparison of the model outputs with time-accurate computational-fluid-dynamics simulations of new maneuvers. Overall, the reduced-order models were found to produce accurate results, although a nonlinear model based on indicial functions yielded the best accuracy among all models. This model, along with a time-dependent surrogate approach, helped to produce accurate predictions for a wide range of motions in the transonic speed range. = regression coefficients ε = kriging random process μ = air viscosity; kriging mean value ρ = density, kg∕m 3 σ 2 = covariance τ ij = viscous stress tensor components, Pa Φ i X = radial basis functions ω = circular frequency, rad∕s

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Section: Reduced-order Models Based On Indicial Functionsmentioning

confidence: 99%

mentioning

confidence: 99%

Transonic Aerodynamic Load Modeling of X-31 Aircraft Pitching Motions

Ghoreyshi¹,

Cummings²,

Ronch³

et al. 2013

AIAA Journal

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“…The most common way of calculating the indicial functions from experimental data is by using harmonic (oscillatory) motions. For example, Reisenthel et al [35] and Reisenthel and Bettencourt [33,34] used this method to approximate the nonlinear indicial functions of a 65 • delta wing. However, the derived indicial functions using harmonic motions depend largely on the quality of motion, e.g.…”

Section: Indicial Response Theorymentioning

confidence: 99%

Unsteady Aerodynamics Modeling for Aircraft Maneuvers: a New Approach Using Time-Dependent Surrogate Modeling

Ghoreyshi

Cummings

2012

30th AIAA Applied Aerodynamics Conference

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A new approach for computing the unsteady and nonlinear aerodynamic loads acting on a maneuvering aircraft is presented based on linear and nonlinear indicial response methods. The novelty of this approach relies on the use of a grid motion technique for CFD calculation of response functions and the development of a time-dependent surrogate model that fits the relationship between flight conditions (Mach number and angle of attack) and responses calculated from a limited number of simulations (samples). The reduced-order model, along with the surrogate model, provides a means for rapid calculation of response functions and predicting aerodynamic forces and moments during maneuvering flight. The maneuvers are generated using a time-optimal prediction code, each covering a different range of angle of attack and motion rates. The side-slip angle ranges from −5 • to 5 • for all maneuvers, and the model assumes that the lateral aerodynamics is linear with side-slip angle over this range. Results presented show that the aircraft studied in the current paper exhibits highly nonlinear roll moments even at low angles of attack which the linear model fails to predict. The results of the new model provide some evidence that, for a certain range of input parameters, in certain maneuvers considered, the predictions match quite well with URANS CFD predictions. The models were at least better than traditional quasisteady predictions. However, for aircraft maneuvering at high angles of attacks, discrepancies are found in lateral coefficients between the model and CFD. At these conditions, the lateral airloads become highly nonlinear with side-slip angle and the model fails to predict these effects. Also, the results show that the CFD calculation of response functions in the high angle of attack flight regime remains a challenging task.Published by Elsevier Masson SAS.

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“…Assuming that the indicial functions are known, the aerodynamic forces and moments induced in any maneuver can be estimated by using the well-known Duhamel superposition integral. 22 Tobak et al 14,15 and Reisenthel et al 23,24 detailed the superposition process for the modeling of unsteady lift and pitch moment from angle of attack and pitch rate indicial functions. Ghoreyshi and Cummings 25 extended this model to include lateral forces and moments as well.…”

Section: -7mentioning

confidence: 99%

Transonic Aerodynamic Loads Modeling of X-31 Aircraft

Ghoreyshi

Post

Cummings

et al. 2012

30th AIAA Applied Aerodynamics Conference

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The generation of reduced order models for computing the unsteady and nonlinear aerodynamic loads on the X-31 aircraft from pitching motions in the transonic speed range is described. The models considered are based on Duhamel's superposition integral using indicial (step) response functions, Volterra theory using nonlinear kernels, Radial Basis functions, and a surrogate-based recurrence framework, both using time-history simulations of a training maneuver(s). One of the biggest challenges in creating these reduced order modeling techniques is accurate identification of unknowns. A large number of step function calculation is required for any combination of angle of attack and free-stream Mach number. A method to efficiently reduce the number of step function calculations is proposed. This method uses a time-dependent surrogate model to fit the relationship between flight conditions (Mach number and angle of attack) and step functions calculated from a limited number of simulations (samples). Each sample itself is directly calculated from unsteady Reynolds-Averaged Navier-Stokes simulations starting from an initial steady-state condition with a prescribed grid motion. An indirect method is proposed to estimate the nonlinear Volterra kernels from time-accurate computational fluid dynamic simulations of different training maneuvers. These maneuvering simulations were also used to estimate the unknown parameters in a model based on Radial Basis functions. A Design of Experiment method was used to generate several pitching motions at different amplitudes and free-stream Mach numbers. The model based on a surrogate-based recurrence framework then approximates the aerodynamic responses induced by pitching motions at new flight conditions. Results are reported for the X-31 configuration with a sharp leading-edge geometry, including canard/wing vortices. The validity of models studied was assessed by comparison of the model outputs with time-accurate computational fluid dynamic simulations of new maneuvers. Overall, the reduced order models were found to produce accurate results, although a nonlinear model based on indicial functions yielded the best accuracy among all models. This model, along with a developed time-dependent surrogate approach, helped to produce accurate predictions for a wide range of motions in the transonic speed range within a few seconds.

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Data-based aerodynamic modeling using nonlinear indicial theory

Cited by 25 publications

References 2 publications

Transonic Aerodynamic Load Modeling of X-31 Aircraft Pitching Motions

Transonic Aerodynamic Load Modeling of X-31 Aircraft Pitching Motions

Unsteady Aerodynamics Modeling for Aircraft Maneuvers: a New Approach Using Time-Dependent Surrogate Modeling

Transonic Aerodynamic Loads Modeling of X-31 Aircraft

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