Computational Study of a Generic T-tail Transport

McMillin, S. Naomi; Frink, Neal T.; Murphy, Patrick C.; Cunningham, Kevin; Shah, Gautam H.; Nayani, Sudheer N.

doi:10.2514/6.2019-0036

Cited by 6 publications

(6 citation statements)

References 10 publications

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“…As noted in the half Lazy-8 predictions, the nonlinear ROM better predicts the lift and pitching moment in comparison to the linear ROM, as it is able to account for nonlinear dependencies on angle of attack and Mach number. The greatest prediction discrepancy occurs in the range of [7][8][9][10][11] seconds, which coincides with a rapid decrease in Mach number from M = 0.15 to M = 0.07. As shown in Appendix B, there is an increasingly transient response in the indicial solutions for lower Mach numbers, suggesting that accurate pitching moment predictions may require increased sampling for Mach numbers approaching incompressible flow levels.…”

Section: Half Lazy-8 and Immelmann Turn Maneuversmentioning

confidence: 87%

“…As opposed to the longitudinal coefficient results, significant differences are apparent between the linear and nonlinear ROM results for the lateral coefficients. These differences are most pronounced in the ranges of [6][7][8] and [11][12][13] seconds, where the nonlinear ROM can account for the variability in the aerodynamic response at nonzero angles of attack. The discrepancy between the nonlinear ROM predictions and CFD simulation data for the yawing moment coefficient may indicate a requirement for increased sampling and/or the inclusion of a dependency on angle of attack for the angular rate contributions.…”

Section: Half Lazy-8 and Immelmann Turn Maneuversmentioning

confidence: 99%

“…The most recent attempt is reported in Refs. [7,8] where the resultant derivatives appear reasonable, but the required computational resources render it impractical for populating large databases.…”

Section: A Efficient System Identificationmentioning

confidence: 99%

“…The status of research in computing ground-to-flight scaling increments and dynamic derivatives for a generic T-tail (GTT) commuter jet is reported in Refs. [7,8]. The search for more efficient techniques to provide computational data for computing dynamic damping derivatives is addressed in this paper.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Reduced-Order Modeling for Aircraft Stability and Control Prediction

Frink

Hiller

Murphy

et al. 2019

AIAA Scitech 2019 Forum

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High-fidelity computational fluid dynamics tools offer the potential to approximate increments for ground-to-flight scaling effects, as well as to augment the dynamic damping derivative data for motion-based flight simulators. Unfortunately, the computational expense is currently prohibitive for populating a complete simulator database. This work investigates an existing surrogate-based, indicial response reduced-order model methodology as a means to efficiently augment a flight simulator database with high-fidelity nonlinear aerodynamic damping derivatives. Creation of the reduced-order model is based on the superposition integrals of the step response with the derivative of its corresponding input signal.Step responses are calculated using a computational grid motion approach that separates the effects of angle of attack and sideslip angle from angular rates, and rates from angle of attack and sideslip. It is demonstrated that the transients produced during the start of a forced-oscillation motion are captured by the reduced-order model to the level of fidelity of a comparable computational solution. Aerodynamic coefficients computed within minutes by the reduced-order model for an aircraft undergoing an 18-second half Lazy-8 maneuver and a 25-second Immelmann turn maneuver are compared with those from full computational flight solutions that required days to complete. Finally, a cost-benefit assessment is included that demonstrates a compelling advantage for this approach.

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Section: Half Lazy-8 and Immelmann Turn Maneuversmentioning

confidence: 87%

Section: Half Lazy-8 and Immelmann Turn Maneuversmentioning

confidence: 99%

Section: A Efficient System Identificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Investigation of Reduced-Order Modeling for Aircraft Stability and Control Prediction

Frink

Hiller

Murphy

et al. 2019

AIAA Scitech 2019 Forum

Self Cite

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show abstract

“…The GTT model was generated from wind tunnel test data by NASA and Boeing [18][19][20] from both static and forced oscillation tests, resulting in a nonlinear but conventional (quasi-steady) flight dynamics model. Further studies were conducted using computational fluid dynamics to establish the effects of Reynolds number on aerodynamics up to and including the post-stall region [21]. In this paper, we augment the quasi-steady aerodynamics in the GTT model provided by NASA Langley (which covers an angle of attack range of -8 o to +60 o and sideslip ±35 o ) with unsteady aerodynamics effects using the state-space method, sometimes referred to as the Goman-Khrabrov model in the literature [22].…”

Section: Introductionmentioning

confidence: 99%

Evaluating Longitudinal Unsteady Aerodynamic Effects in Stall for a T-Tail Transport Model

Nguyen

Goman

Lowenberg

et al. 2022

Journal of Aircraft

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Although there have been many proposed methods to model unsteady aerodynamic effects in the stall and post-stall region, little work has been done to directly assess the impact of unsteady aerodynamic models on stability and control characteristics. In this paper, we combine the state-space method for unsteady aerodynamic modelling with bifurcation analysis to examine the sensitivity of stall and post-stall behaviour to the choice of aerodynamic modelling method: quasi-steady or unsteady. It is found that quasi-steady modelling can adequately capture the dynamics of the chosen example of a T-tailed transport aircraft with negligible wing-tail coupling. The study is then expanded to investigate a hypothetical situation with highly unsteady aerodynamic characteristics resembling a delta wing configurationachieved by increasing the time delay constants in the unsteady model. This results in an aircraft with significantly lower flying qualities as indicated by bifurcation analysis. These findings highlight the need to implement unsteady aerodynamic modelling techniques in high-performance aircraft with significant vortex-related unsteady aerodynamics in order to sufficiently capture their stall and post-stall dynamics.

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Unsteady Model Estimation for Generic T-Tail Transport Aircraft Using Computational Data

Murphy

Frink

McMillin

et al. 2019

AIAA Scitech 2019 Forum

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Computational Study of a Generic T-tail Transport

Cited by 6 publications

References 10 publications

Investigation of Reduced-Order Modeling for Aircraft Stability and Control Prediction

Investigation of Reduced-Order Modeling for Aircraft Stability and Control Prediction

Evaluating Longitudinal Unsteady Aerodynamic Effects in Stall for a T-Tail Transport Model

Unsteady Model Estimation for Generic T-Tail Transport Aircraft Using Computational Data

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