Large eddy simulation of aircraft wake vortices within homogeneous turbulence - Crow instability

Han, Je-Chin; Lin, Yuh-Lang; Schowalter, David; Arya, S. Pal; Proctor, Fred H.

doi:10.2514/3.14409

Cited by 24 publications

(30 citation statements)

References 16 publications

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“…Specifications for the domain and grid size are shown in Table 2. The width and height of the domain is larger than in our earlier studies, 14,15 in order to minimize boundary influences during the ring-vortex phase of evolution. Prior to vortex initialization, an initial field of resolved-scale turbulence is allowed to develop under an artificial external forcing at low wavenumbers.…”

Section: Initial Conditionsmentioning

confidence: 97%

“…Prior to vortex initialization, an initial field of resolved-scale turbulence is allowed to develop under an artificial external forcing at low wavenumbers. 15,20,21 As shown in Figure 2, the turbulence field is allowed to develop until the turbulence statistics become nearly steady (about 18 eddy turn-over times).…”

Section: Initial Conditionsmentioning

confidence: 99%

“…14,15,16 The model, being LES, explicitly resolves scales of turbulence larger than the grid size, while modeling subgrid scales via turbulence closure approximations. The subgrid turbulence formulation is dependent upon the local flow deformation, stratification, and flow rotation.…”

Section: Les Modelmentioning

confidence: 99%

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Three-Phased Wake Vortex Decay

Proctor

Ahmad

Switzer

et al. 2010

AIAA Atmospheric and Space Environments Conference

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A detailed parametric study is conducted that examines vortex decay within turbulent and stratified atmospheres. The study uses a large eddy simulation model to simulate the out-of-ground effect behavior of wake vortices due to their interaction with atmospheric turbulence and thermal stratification. This paper presents results from a parametric investigation and suggests improvements for existing fast-time wake prediction models. This paper also describes a three-phased decay for wake vortices. The third phase is characterized by a relatively slow rate of circulation decay, and is associated with the ringvortex stage that occurs following vortex linking. The three-phased decay is most prevalent for wakes imbedded within environments having low-turbulence and near-neutral stratification. Nomenclature

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Section: Initial Conditionsmentioning

confidence: 97%

Section: Initial Conditionsmentioning

confidence: 99%

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Three-Phased Wake Vortex Decay

Proctor

Ahmad

Switzer

et al. 2010

AIAA Atmospheric and Space Environments Conference

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“…Fast-time models are based on a number of assumptions which limit their accuracy and range of application. Fast-time models do not provide the wake-vortex flow field details found in Large Eddy Simulation (LES) models such as can be provided with the Terminal Area Simulation System (TASS) 10,11 . Fast-time models can not directly predict the meandering vortex paths resulting from atmospheric turbulence, sinusoidal displacements ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Fast-Time Wake Vortex Prediction Models

Proctor

Hamilton²

2009

47th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Current fast-time wake models are reviewed and three basic types are defined. Predictions from several of the fast-time models are compared. Previous statistical evaluations of the APA-Sarpkaya and D2P fast-time models are discussed. Root Mean Square errors between fast-time model predictions and Lidar wake measurements are examined for a 24 hr period at Denver International Airport. Shortcomings in current methodology for evaluating wake errors are also discussed.

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“…Favorable conditions can lead to vortex linking and breakup with the subsequent formation of vortex rings. Vortex deformation has been investigated in detail during flight tests [5,6], experimentally [7,8] and by numerical simulation [9][10][11][12]. Recently, De Visscher et al [13] used large-eddy simulations (LESs) to study the influence of combined atmospheric turbulence and stratification on the wake-vortex evolution (transport, decay, and topology).…”

mentioning

confidence: 99%

Simulation Methods for Aircraft Encounters with Deformed Wake Vortices

Bieniek¹,

Luckner²,

Visscher³

et al. 2016

Journal of Aircraft

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Simulation of aircraft wake-vortex encounters is regularly applied in the research toward revised aircraft separation minima. Most encounter flight simulation studies have used a pair of straight counter-rotating vortices. However, after being shed by the generating aircraft, the wake vortices begin to develop a growing deformation due to the long-wave Crow instability, especially under low-turbulent atmospheric conditions when vortices decay slowly. In this study, two methods for simulation of aircraft encounters with such perturbed wake vortices are described and compared. The first method uses a vortex simulation model, which is based on analytical models of the deformation that consider the large-scale vortex shapes. The second method applies vortex-velocity fields from high-fidelity largeeddy simulations. It offers the highest possible level of realism and is used as the reference. The resulting aircraft responses induced by wavy vortices and vortex rings are reproduced with good quality by the vortex simulation model. The comparison of both methods shows that the vortex simulation model captures the overall impact of vortex deformation on the aircraft upsets. It can be used for future safety assessments that require a large number of encounter simulations.

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Large eddy simulation of aircraft wake vortices within homogeneous turbulence - Crow instability

Cited by 24 publications

References 16 publications

Three-Phased Wake Vortex Decay

Three-Phased Wake Vortex Decay

Evaluation of Fast-Time Wake Vortex Prediction Models

Simulation Methods for Aircraft Encounters with Deformed Wake Vortices

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