Study of aircraft wake vortex behavior near the ground

Zheng, Zhongquan Charlie; Ash, Robert L.

doi:10.2514/3.13107

Cited by 70 publications

(42 citation statements)

References 23 publications

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“…Recent studies have used: two-dimensional laminar or DNS, 37,38,39 three-dimensional DNS, 40,41 twodimensional RANS, 42 two-dimensional LES, 43 and threedimensional LES. 44,45,46 In order to better understand wake vortex behavior and develop relationships with environmental parameters, numerical modelling is being carried out with the Terminal Area Simulation System 47,48 (TASS) in both two and three dimensions.…”

Section: Wake Vortex Modellingmentioning

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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Section: Wake Vortex Modellingmentioning

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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“…Widnall et al 18 showed that the shortwavelength instability found by Crow is spurious since its predicted wavelength violates the assumptions of the model. The analysis of Widnall et al is valid for slender vortices (a/bӶ1, where a is the core diameter͒ and kaϭO (1), where k is the wavenumber. This analysis is therefore appropriate for short-wavelength disturbances, as opposed to the analysis of Crow which requires kaӶ1.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, trailing vortices from aircraft which interact with the ground can present a danger to following aircraft. 1 In assessing the danger it is important to understand the motion, structure, and decay of the vortices. These characteristics could be strongly influenced by three-dimensional effects.…”

Section: Introductionmentioning

confidence: 99%

The three-dimensional interaction of a vortex pair with a wall

Luton

Ragab

1997

Physics of Fluids

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Articles you may be interested inThe onset of three-dimensional centrifugal global modes and their nonlinear development in a recirculating flow over a flat surface Phys. Fluids 22, 114102 (2010) The interaction of vortices passing near a solid surface has been examined using direct numerical simulation. The configuration studied is a counter-rotating vortex pair approaching a wall in an otherwise quiescent fluid. The focus of these simulations is on the three-dimensional effects, of which little is known. To the authors' knowledge, this is the first three-dimensional simulation that lends support to the short-wavelength instability of the secondary vortex. It has been shown how this Crow-type instability leads to three dimensionality after the rebound of a vortex pair. The growth of the instability of the secondary vortex in the presence of the stronger primary vortex leads to the turning and intense stretching of the secondary vortex. As the instability grows the secondary vortex is bent, stretched, and wrapped around the stronger primary. During this process reconnection was observed between the two secondary vortices. Reconnection also begins between the primary and secondary vortices but the weaker secondary vortex dissipates before the primary, leaving reconnection incomplete. Evidence is presented for a new type of energy cascade based on the short-wavelength instability and the formation of continual smaller vortices at the wall. Ultimately the secondary vortex is destroyed by stretching and dissipation leaving the primary vortex with a permanently distorted shape but relatively unaffected strength compared to an isolated vortex.

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“…A numerical large-eddy simulation model called the Terminal Area Simulation System 2 (TASS) has been modified for application to aircraft wake vortex simulations. The TASS model, which is described in section 2, is believed to have an advantage over other wake vortex models 3,4,5,6,7,8 in that it has a meteorological reference frame, compressible nonBoussinesq equation set, subgrid turbulence closure, a formulation for ground-friction, realistic boundary conditions, an option for either two or three spatial dimensions, and accurate --yet computationally efficient --numerical approximations. In spite of the model's sophistication, it has relatively fast execution times, which is an important feature when taking on the ambitious task of simulating three-dimensional, timedependent aircraft wakes.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of wake vortices measured during the Idaho Falls and Memphis field programs

Proctor

1996

14th Applied Aerodynamics Conference

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A numerical large-eddy simulation model is under modification and testing for application to aircraft wake vortices. The model, having a meteorological framework, permits the interaction of wake vortices with environments characterized by crosswind shear, stratification, and humidity. As part of the validation process, model results are compared with measured field data from the 1990 Idaho Falls and the 1994-1995 Memphis field experiments. Cases are selected that represent different aircraft and a cross section of meteorological environments. Also included is one case with wake vortex generation in ground effect. The model simulations are initialized with the appropriate meteorological conditions and a post roll-up vortex system. No ambient turbulence is assumed in our initial set of experiments, although turbulence can be self generated by the interaction of the model wakes with the ground and environment.

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Study of aircraft wake vortex behavior near the ground

Cited by 70 publications

References 23 publications

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

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

The three-dimensional interaction of a vortex pair with a wall

Numerical simulation of wake vortices measured during the Idaho Falls and Memphis field programs

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