Analysis of a Wing Moving Through a Nonlinear Gust

Moushegian, Alex; Smith, Marilyn J.

doi:10.2514/6.2019-0637

Cited by 8 publications

(6 citation statements)

References 12 publications

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“…The presence of highly separated flows, shear layers, and turbulence requires extremely large meshes and, at minimum, large-eddy simulations in the wakes and separation regions (Gross 2014, Hodara & Smith 2017, Liggett & Smith 2012, Mohamed et al 2015, Smith et al 2011. The influence of higher frequencies superimposed on a discrete gust was evaluated during a computational assessment of experiments on a sharp-edged gust with a width equal to two wing chordlengths (Grubb et al 2020, Moushegian et al 2019). The experimental gust, with a gust ratio of 1.0, included higher frequencies from the gust jet.…”

Section: Computational Considerationsmentioning

confidence: 99%

“…When gust ratios become large and separation occurs, these terms can no longer be neglected (Badrya et al 2021). An overset mesh with dynamic motion can model the moving wing with the stationary gust created via the source terms (Badrya et al 2021) or via jet boundary conditions (Moushegian et al 2019). Without source terms (requiring code modification), the gust may be modeled by a dual set of jet boundary conditions that provide both an entrance and an exit so that the gust velocity is maintained in the simulation.…”

Section: Computational Considerationsmentioning

confidence: 99%

“…This may require the computational domain to be truncated to incorporate the jet boundary conditions, as well as a refined mesh to ensure that numerical dissipation does not change the problem. For solvers without overset meshes and access to a source code, researchers have developed a new set of jet boundary conditions that translate with respect to the wing (Grubb et al 2020, Moushegian et al 2019. This approach has been successfully validated with experimental data (Corkery et al 2018), and the limitations are comparable to the overset method with static jet boundary conditions.…”

Section: Computational Considerationsmentioning

confidence: 99%

See 2 more Smart Citations

Physics and Modeling of Large Flow Disturbances: Discrete Gust Encounters for Modern Air Vehicles

Jones

Çeti̇ner

Smith

2022

Annu. Rev. Fluid Mech.

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Gusts of moderate and large magnitude induce flow separation and other complexities when they interact with the lifting surfaces of air vehicles. The presence of these nonlinear gusts are becoming ubiquitous in twenty-first-century air vehicles, where the classic potential flow–based methodologies applied in the past may no longer be valid. In this review, we define the parameter space for the presence of large-amplitude gusts and describe where and when these gusts may primarily be found. Recent research using modern experimental and computational techniques to define the limits of classical unsteady and indicial aerodynamic theories is summarized, with a focus on discrete transverse, streamwise (longitudinal), and vortex gust encounters. We propose areas where future research is needed to transition these studies of large-amplitude gust physics to real-time prediction and mitigation during flight. Expected final online publication date for the Annual Review of Fluid Mechanics, Volume 54 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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Section: Computational Considerationsmentioning

confidence: 99%

Section: Computational Considerationsmentioning

confidence: 99%

Section: Computational Considerationsmentioning

confidence: 99%

See 1 more Smart Citation

Physics and Modeling of Large Flow Disturbances: Discrete Gust Encounters for Modern Air Vehicles

Jones

Çeti̇ner

Smith

2022

Annu. Rev. Fluid Mech.

Self Cite

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“…In UAM applications, urban environments where the flow includes large transients and gusts (Ref. 8) can trigger dynamic stall through new mechanisms. The ability to predict the onset of dynamic stall, to avoid or control it will be key to both military and civilian applications.…”

Section: Background and Motivationmentioning

confidence: 99%

“…This experimental work, in collaboration with the CFD work of Smith at GT (Refs. 8,112), seeks to understand how and where unsteady separation occurs. Then, it decomposes the forces so that researchers can The computational part of the work uses CFD to permit rapid analysis of the sensitivity to scaling and similarity parameters.…”

Section: Current Endeavors: Circulation-basedmentioning

confidence: 99%

Rotating Wing Dynamic Stall: State of the Art and Future Directions

Gardner

Jain

et al. 2020

Proceedings of the Vertical Flight Society 76th Annual Forum

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Dynamic stall has been studied for more than fifty years; in the last decade significant advances have been accomplished in the understanding, prediction, modeling and control of dynamic stall on rotors. In September 2019, an Army Research Office-funded workshop was held at the Georgia Institute of Technology to evaluate the state of the art and future directions in the understanding and control of dynamic stall found on rotors, specifically for vertical lift vehicles. Approximately forty attendees drawn from top experts in the field to graduate students convened to discuss experimental, computational, theoretical, and control research in the field over a two-day period. This paper provides a summary of the findings from this workshop, including a synopsis of best practices for experiments and first-principles-based computational prediction of rotor dynamic stall. Experimental data sets are discussed, as well the direction of research for empirical (non-first-principles) modeling and control of dynamic stall.

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Wind tunnel effects on gust-interaction simulations

Beckers

Eldredge

2023

Theor. Comput. Fluid Dyn.

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Large-amplitude flow disturbances such as gusts can drastically change the aerodynamic loads on machines. Developing active flow control strategies to mitigate these gusts is challenging because the flow response depends non-linearly on the gust parameters. Wind-tunnel experiments and computational models can explore this parameter space but suffer from individual limitations such as a sensor's limited field of view or modeling uncertainties. However, combining both tools through data assimilation can alleviate some issues and generate richer data sets. For accurate results, it is important that the computational model can realistically predict the flow in the wind tunnel. For this purpose, we present a computational model (a digital twin) for a low-speed aerodynamics wind tunnel with irrotational gust generation using suction at the top of the test section. The model couples a viscous flow solution without wind-tunnel walls with a potential flow to correct the normal velocity at the walls and model the suction. We demonstrate the simulation of gust responses using three examples and compare different airfoils and approximations to show their effects. In the last example, we illustrate how to apply this model for data assimilation with experiments by inferring the time-varying gust strength from synthetic velocity measurements.

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Analysis of a Wing Moving Through a Nonlinear Gust

Cited by 8 publications

References 12 publications

Physics and Modeling of Large Flow Disturbances: Discrete Gust Encounters for Modern Air Vehicles

Physics and Modeling of Large Flow Disturbances: Discrete Gust Encounters for Modern Air Vehicles

Rotating Wing Dynamic Stall: State of the Art and Future Directions

Wind tunnel effects on gust-interaction simulations

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