Numerical Simulation of Aircraft Trailing Vortices Interacting with Ambient Shear or Ground

Mokry, M.

doi:10.2514/2.2840

Cited by 17 publications

(10 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…9 or 11. Another model that accountsfor effects of ambient turbulence,crosswind shear, and ground proximity was proposed by Kantha. 14 Recently, Mokry 15 presented a two-dimensional continuous vortex sheet method that captures vortex sheet rollup, interaction with ambient shear layers and the ground. Note that despite the signi cant number of available wake vortex models none of these models considers all effects of the rst-order impact parameters,which are aircraft con guration,turbulence,stable strati cation, shear, and proximity of the ground.…”

Section: Introductionmentioning

confidence: 99%

Probabilistic Two-Phase Wake Vortex Decay and Transport Model

Holzäpfel

2003

Journal of Aircraft

188

104

View full text Add to dashboard Cite

A new parametric wake vortex transport and decay model is proposed that predicts probabilistic wake vortex behavior as a function of aircraft and environmental parameters in real time. The probabilistic two-phase wake vortex decay model (P2P) accounts for the effects of wind, turbulence, stable strati cation, and ground proximity. The model equations are derived from the analytical solution of the spatiotemporal circulation evolution of the decaying potential vortex and are adapted to wake vortex behavior as observed in large-eddy simulations. Vortex decay progresses in two phases, a diffusion phase followed by rapid decay. Vortex descent is a nonlinear function of vortex strength. Probabilistic components account for deviations from deterministic vortex behavior inherently caused by the stochastic nature of turbulence, vortex instabilities, and deformations, as well as uncertainties and uctuations that arise from environmental and aircraft parameters. The output of P2P consists of con dence intervals for vortex position and strength. To assign a de ned degree of probability to the predictions reliably, the model design allows for the continuous adjustment of decay parameters and uncertainty allowances, based on a growing amount of data. The application of a deterministic version of P2P to the Memphis wake vortex database yields favorable agreement with measurements. Nomenclature

show abstract

Section: Introductionmentioning

confidence: 99%

Probabilistic Two-Phase Wake Vortex Decay and Transport Model

Holzäpfel

2003

Journal of Aircraft

188

104

View full text Add to dashboard Cite

show abstract

“…Although the current study was limited to vortex decay without significant change in the vortex signature, more realistic models of vortex evolution and distortion produced by the effects of stratification (e.g., Hill 1975;Robins and Delisi 1990;Spalart 1996;Proctor et al 1997;Holzäpfel and Gerz 2001), wind shear (e.g., Kantha 1996Kantha , 1998Proctor et al 1997;Hofbauer and Gerz 2000;Mokry 2001), and ground effects (e.g., Kantha 1996Kantha , 1998Sarpkaya 2000) could be investigated by using LES of the vortex pair. From the wind fields derived from a suitably high resolution (as defined above) LES, an empirical description of the vortex parameters may be derived that can then be used to perform ML performance estimates of the lidar under these conditions.…”

Section: Summary and Discussionmentioning

confidence: 99%

Maximum Likelihood Estimates of Vortex Parameters from Simulated Coherent Doppler Lidar Data

Frehlich

Sharman

2005

Journal of Atmospheric and Oceanic Technology

View full text Add to dashboard Cite

The performance of pulsed coherent Doppler lidar in estimating aircraft trailing wake vortices by scanning across the aircraft flight track is evaluated using Monte Carlo lidar simulations of a simple vortex pair in both a nonturbulent and turbulent environment. The performance estimates are based on maximum likelihood estimates of aircraft wake vortex parameters and provide a measure of the ability of the lidar to detect and track wake vortices under the best possible conditions. Two aircraft types are considered: the Boeing 737 and the Boeing 747. Rigorous error analyses are produced by comparing the estimated parameters from numerical simulations of raw lidar data with the known input parameters of the simulation. It is shown that the probability density functions for the estimates are approximately Gaussian and the bias is very small. The main source of the bias was determined to be the movement of the vortex during the lidar scan. The estimation error is increased by the effects of a background turbulent velocity field. The trade-off between lidar pulse energy and pulse repetition frequency for the standard condition of constant laser power is also presented. It is shown that these maximum likelihood estimates provide accurate detection and tracking of the key vortex parameters for a simple vortex model, with and without background turbulence.

show abstract

“…In this paper, the method of discrete vortex sheets [13] is used to provide numerical simulations of various types of vortex mergers. An advantage of this method is that it conserves vorticity and allows the solution to develop over relatively large times.…”

Section: Discrete Vortex Sheet Methodsmentioning

confidence: 99%

“…Comparing Eqs. (13) and (21) we obtain the relationship between the vortex line density and the vorticity inside the patch…”

Section: Interaction Of Vortex Patchesmentioning

confidence: 99%

See 1 more Smart Citation

The Vortex Merger Factor in Aircraft Wake Turbulence

Mokry¹

2005

Aeronaut. j.

View full text Add to dashboard Cite

Vortex merger is studied within the context of twodimensional discrete vortex sheets and demonstrated on two equally oriented circular vortices and aircraft tip and flap vortices. It is confirmed that, depending on the wing load distribution, the latter may or may not coalesce into a single counter-rotating pair. The interaction of a vortex with an equally oriented shear layer, governed by the same physical principle, suggests a possible intensification of an aircraft vortex in cross-wind shear.

show abstract

Numerical Simulation of Aircraft Trailing Vortices Interacting with Ambient Shear or Ground

Cited by 17 publications

References 22 publications

Probabilistic Two-Phase Wake Vortex Decay and Transport Model

Probabilistic Two-Phase Wake Vortex Decay and Transport Model

Maximum Likelihood Estimates of Vortex Parameters from Simulated Coherent Doppler Lidar Data

The Vortex Merger Factor in Aircraft Wake Turbulence

Contact Info

Product

Resources

About