Effects of Environmental and Aircraft Parameters on Wake Vortex Behavior

Holzäpfel, Frank

doi:10.2514/1.c032366

Cited by 29 publications

(40 citation statements)

References 28 publications

(55 reference statements)

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“…In the current implementation of the MCS code, the initial vortex pair separation b 0 can either be held constant, based on the elliptical wing loading, or varied between 0.95b 0 and b 0 , based on Holzäpfel [7]. Likewise, the initial circulation can be held constant or varied within a fixed interval.…”

Section: Generation Of Initial Conditionsmentioning

confidence: 99%

“…To overcome this shortcoming, the perturbed crosswind profiles are generated by adding evenly spaced constant values in the interval [−1.26, 1.26 m∕s] to the ambient vertical profile. The specified interval is based on uncertainties expected in the wind measuring sensors on the aircraft [7].…”

Section: Generation Of Initial Conditionsmentioning

confidence: 99%

“…Likewise, the initial circulation can be held constant or varied within a fixed interval. In this study, b 0 is held constant, and the initial circulation value is varied between 0.9-1.25 Γ 0 [7].…”

Section: Generation Of Initial Conditionsmentioning

confidence: 99%

“…The initial vortex locations can be either constant values or random perturbations from a uniform distribution or normal distributions with (e.g., a mean of y 0 and σ 25 m in the lateral direction, and a mean of z 0 with σ 7 m based on Holzäpfel [7]). In this study, perturbations in z 0 are based on a normal distribution with mean set to z 0 and σ 7 m. If the aircraft is in IGE, then σ is set to 4 m. Perturbations in the lateral position are introduced based on a normal distribution with mean set to y 0 and σ 13 m [7].…”

Section: Generation Of Initial Conditionsmentioning

confidence: 99%

“…In addition, the vortices undergo complex interactions with the ground. Substantial effort has been made in the past to understand the governing physics of vortex dynamics [2][3][4][5][6][7][8] and to develop wakevortex prediction models [9][10][11][12][13][14][15][16][17] to enhance the capacity of the airspace while maintaining the safety.…”

mentioning

confidence: 99%

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Multimodel Ensemble Methods for Prediction of Wake-Vortex Transport and Decay

Körner

Ahmad

Holzäpfel

et al. 2017

Journal of Aircraft

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Several multimodel ensemble methods are selected and further developed to improve the deterministic and probabilistic prediction skills of individual wake-vortex transport and decay models. The different multimodel ensemble methods are introduced, and their suitability for wake applications is demonstrated. The selected methods include direct ensemble averaging, Bayesian model averaging, and Monte Carlo simulation. The different methodologies are evaluated employing data from wake-vortex field measurement campaigns conducted in the United States and Germany.= forecast of ith model g i yjf i = probability density function of forecast L = likelihood PB = probability that B occurs PBjA = probability that B occurs, given that A occurs py = probability density function of the y forecast

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Section: Generation Of Initial Conditionsmentioning

confidence: 99%

Section: Generation Of Initial Conditionsmentioning

confidence: 99%

Section: Generation Of Initial Conditionsmentioning

confidence: 99%

Section: Generation Of Initial Conditionsmentioning

confidence: 99%

mentioning

confidence: 99%

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Multimodel Ensemble Methods for Prediction of Wake-Vortex Transport and Decay

Körner

Ahmad

Holzäpfel

et al. 2017

Journal of Aircraft

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Aircraft‐type dependency of contrail evolution

Unterstraßer

Görsch

2014

JGR Atmospheres

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The impact of aircraft type on contrail evolution is assessed using a large eddy simulation model with Lagrangian ice microphysics. Six different aircraft ranging from the small regional airliner Bombardier CRJ to the largest aircraft Airbus A380 are taken into account. Differences in wake vortex properties and fuel flow lead to considerable variations in the early contrail geometric depth and ice crystal number. Larger aircraft produce contrails with more ice crystals (assuming that the number of initially generated ice crystals per kilogram fuel is constant). These initial differences are reduced in the first minutes, as the ice crystal loss during the vortex phase is stronger for larger aircraft. In supersaturated air, contrails of large aircraft are much deeper after 5 min than those of small aircraft. A parameterization for the final vertical displacement of the wake vortex system is provided, depending only on the initial vortex circulation and stratification. Cloud resolving simulations are used to examine whether the aircraft-induced initial differences have a long-lasting mark. These simulations suggest that the synoptic scenario controls the contrail cirrus evolution qualitatively. However, quantitative differences between the contrail cirrus properties of the various aircraft remain over the total simulation period of 6 h. The total extinctions of A380-produced contrails are about 1.5 to 2.5 times higher than those from contrails of a Bombardier CRJ.

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Development of a potential vortex-hazard index to predict cruise-level wake turbulence encounters

2019

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A pair of counter-rotating trailing vortices formed as a consequence of lift generation poses a potential threat to the encountering aircraft. In recent years, incidents/accidents involving wake turbulence confrontation at cruise altitude are increasing due to increase in the number of super-heavy category aircraft. The vertical separation distance between two airplanes guided by the Federal Aviation Administration (FAA) could be inadequate in certain cases. In this article, a new approach has been proposed to predict the probable area of the persistence of trailing vortices produced by large aircraft. It includes the development of an index with multiple atmospheric effects on the vortices. Also, the impact of the wake from a distinct airplane is incorporated. The performance assessment of the index in predicting the cruise-level wake vortex encounters has been made using various scenarios that happened in the recent past. Weather Research and Forecasting (WRF) model is employed to simulate the atmospheric flow conditions of chosen situations. We found that the method successfully predicts all the cases considered in this study.

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Effects of Environmental and Aircraft Parameters on Wake Vortex Behavior

Cited by 29 publications

References 28 publications

Multimodel Ensemble Methods for Prediction of Wake-Vortex Transport and Decay

Multimodel Ensemble Methods for Prediction of Wake-Vortex Transport and Decay

Aircraft‐type dependency of contrail evolution

Development of a potential vortex-hazard index to predict cruise-level wake turbulence encounters

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