NASA wake vortex research for aircraft spacing

Perry, R. B.; Hinton, David A.; Stuever, Robert A.

doi:10.2514/6.1997-57

Cited by 40 publications

(11 citation statements)

References 7 publications

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“…In general, the fast-time wake-vortex models are empirical algorithms used for fast predictions of wake transport and decay, based on aircraft parameters and ambient weather conditions. The models used in this study include the Aircraft Vortex Spacing System (AVOSS) Prediction Algorithm (APA) [32][33][34][35][36], Terminal Area Simulation System (TASS) Derived Algorithms for Wake Prediction (TDP) [14,37], and the deterministic two-phase wake-vortex decay and transport model (D2P) [12,13]. The APA and TDP models have been developed by NASA, whereas D2P has been developed by DLR.…”

Section: Fast-time Wake Transport and Decay Modelsmentioning

confidence: 99%

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: Fast-time Wake Transport and Decay Modelsmentioning

confidence: 99%

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

Körner

Ahmad

Holzäpfel

et al. 2017

Journal of Aircraft

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“…The system, called the Aircraft Vortex Spacing System (AVOSS), 1,2,3,4 will determine safe operating spacings between arriving and departing aircraft based on the observed/predicted weather state. This system should provide a safe reduction in separation of aircraft compared to the now-existing flight rules, which are conservatively-based on aircraft weight categories.…”

Section: Introductionmentioning

confidence: 99%

The NASA-Langley wake vortex modelling effort in support of an operational aircraft spacing system

Proctor

1998

36th AIAA Aerospace Sciences Meeting and Exhibit

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Two numerical modelling efforts, one using a large eddy simulation model and the other a numerical weather prediction model, are underway in support of NASA's Terminal Area Productivity program. The large-eddy simulation model (LES) has a meteorological framework and permits the interaction of wake vortices with environments characterized by crosswind shear, stratification, humidity, and atmospheric turbulence. Results from the numerical simulations are being used to assist in the development of algorithms for an operational wake-vortex aircraft spacing system. A mesoscale weather forecast model is being adapted for providing operational forecast of winds, temperature, and turbulence parameters to be used in the terminal area.This paper describes the goals and modelling approach, as well as achievements obtained to date. Simulation results will be presented from the LES model for both two and three dimensions. The 2-D model is found to be generally valid for studying wake vortex transport, while the 3-D approach is necessary for realistic treatment of decay via interaction of wake vortices and atmospheric boundary layer turbulence. Meteorology is shown to have an important affect on vortex transport and decay. Presented are results showing that wake vortex transport is unaffected by uniform fog or rain, but wake vortex transport can be strongly affected by nonlinear vertical change in the ambient crosswind. Both simulation and observations show that atmospheric vortices decay from the outside with minimal expansion of the core. Vortex decay and the onset three-dimensional instabilities are found to be enhanced by the presence of ambient turbulence. Nomenclature

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“…This is the motivation for the current research on the topic (1)(2)(3)(4)(5)(6) . The separation rules of ICAO and FAA are empirical, and can be compared with a formula for the separation distances (7) .…”

Section: Introductionmentioning

confidence: 99%

On the compensation and damping of roll induced by wake vortices

Campos¹,

Marques

2014

Aeronaut. j. (1968)

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The effect of the wake of a leading aircraft on a following aircraft is demonstrated by calculating the rolling motion consisting of three terms: (i) the free rolling motion due to initial bank angle and roll rate; (ii) the forced wake response due the rolling moment induced by the wake encounter; (iii) the forced control response due to aileron deflection to counter the wake vortex effects. It is shown that in the absence of control action, the roll rate of the following aircraft goes through a peak, and then decays, leading to a constant asymptotic bank angle; the latter is a measure of the magnitude of the wake effect, e.g. is larger for weaker damping. The exact analytical solution of the roll equation appears as a power series of a damping factor, whose coefficients are exponential integrals of time; it is shown that the first two terms give an accuracy better than 2%. The theory is used to simulate 15 combinations of wake vortex encounters between leading and following aircraft in the five ICAO/FAA weight categories: light, medium, heavy, special (B757) and very large (A380).

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NASA wake vortex research for aircraft spacing

Cited by 40 publications

References 7 publications

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

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

The NASA-Langley wake vortex modelling effort in support of an operational aircraft spacing system

On the compensation and damping of roll induced by wake vortices

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