Characterization of Aircraft Wake Vortex Circulation Decay in Reasonable Worst Case Conditions

Visscher, Ivan De; Winckelmans, Grégoire; Treve, Vincent

doi:10.2514/6.2016-1603

Cited by 9 publications

(21 citation statements)

References 5 publications

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“…An overview on the RECAT-EU methodology is provided by Rooseleer et al (2016). Details with respect to the characterisation of wake vortex circulation decay in reasonable worst-case conditions can be found in Bourgeois, Choroba, and Winckelmans (2012) and De Visscher and Winckelmans (2016), while the encounter severity metric is described in De Visscher, Winckelmans, and Treve (2015).…”

Section: Recat-eu Methodologymentioning

confidence: 99%

“…During the Vienna campaign lidar measurements were conducted in five vertical planes in order to characterise vortex decay in front, above, between and behind the two plate lines and to demonstrate E6-10 F. Holzäpfel, D. Vechtel, G. Rotshteyn and A. Stephan that wake vortices encounter risks are alleviated by the installation of plate lines all along that part of the final approach, where wake vortices may endanger follower aircraft by rebounding into the flight corridor (Holzäpfel et al, 2021). In contrast, RECAT-EU considers a flight altitude of one wing span above ground as an integral element of the identified reasonable worst-case conditions (De Visscher & Winckelmans, 2016). As this aircraft type specific flight altitude cannot be realised for various aircraft types within a single measurement plane, even with dedicated measurement set-ups, the vortex measurements are adjusted in time, such that the considered vortex evolutions always begin at a height of one wing span of the vortex generator aircraft.…”

Section: Reasonable Worst-case Decay Curvesmentioning

confidence: 99%

“…In order to generate the reasonable worst-case circulation decay curve, RECAT-EU employs the top 2% of the most long-lasting wakes corresponding to those vortices with a measured normalised lifetime beyond t* = 5 for B744 aircraft (De Visscher & Winckelmans, 2016). Initial circulation is normalised by 𝛤 0 estimated via the two-phase decay model fits and the vortex age is normalised with the vortex time scale, t 0 , based on the b 0 and 𝛤 0 estimates following (4.2).…”

Section: Reasonable Worst-case Decay Curvesmentioning

confidence: 99%

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Plate lines to enhance wake vortex decay for reduced separations between landing aircraft

Holzäpfel

Vechtel

Rotshteyn

et al. 2022

Flow

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To mitigate the risk of wake vortex encounters during final approach, so-called plate lines have been developed. Data collected during a six-month measurement campaign at Vienna International Airport are used to assess the potential for reducing minimum aircraft separations facilitated by plate lines during approach and landing following the re-categorisation (RECAT-EU) methodology for revised wake turbulence categorisation. To ensure that no other parameters controlling wake vortex decay bias the analysis, it is verified that wind speed, atmospheric turbulence, thermal stratification and flight altitude reside in similar ranges with and without the plates. The analysis follows the steps of the RECAT-EU method to generate non-dimensional so-called reasonable worst-case circulation decay curves; one as a reference for nominal operations without plates and one representing the accelerated wake vortex decay brought about by the plate lines. The difference between the two circulation decay curves corresponds to the non-dimensional time-based aircraft separation reduction potential that can be translated into distance-based separation gains. Depending on the particular RECAT-EU category combination, the attained aircraft separation reduction potential ranges between 12% and 15%. Constricting the analysis to wake vortices generated by one aircraft type representing the Upper Heavy RECAT-EU category, the separation reduction potential amounts up to 24%.

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Section: Recat-eu Methodologymentioning

confidence: 99%

Section: Reasonable Worst-case Decay Curvesmentioning

confidence: 99%

Section: Reasonable Worst-case Decay Curvesmentioning

confidence: 99%

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Plate lines to enhance wake vortex decay for reduced separations between landing aircraft

Holzäpfel

Vechtel

Rotshteyn

et al. 2022

Flow

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“…In this way, the encounter of the WV with the following aircraft can be dangerous due to the down-wash velocity and induced rolling moment as shown in Figure 1. [5][6][7][8][9][10][11] In order to prevent wake turbulence effects that can cause serious damage to the following aircraft, ICAO has presented a separation scheme that classifies aircraft into three categories according to their maximum take-off weight (Table 1). A new proposal has been developed by European Organization for the Safety of Air Navigation (EUROCONTROL), which includes a 6-category separation scheme named "RECAT-EU" as a revision to the safe but extremely conservative ICAO 3-category separation scheme.…”

Section: Introductionmentioning

confidence: 99%

Characterization modeling of wake vortex circulation decay under reasonable worst case conditions with cuckoo search algorithm

Oruc,

Baklacioglu,

Sahin

2024

Proceedings of the Institution of Mechanical Engineers, Part G:

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Wake vortex (WV) produced by a large aircraft has the potential to cause serious damage to smaller aircraft following it. In this context, characterization of WV circulation decay under the reasonable worst case (RWC) conditions allows the separation minima to be found safely. In this study, modeling of dimensionless decay curves, which were developed using three experimental LIDAR (Light Detection and Ranging) datasets in the RECAT-EU project and is a useful tool to characterize the wake vortex circulation decay under RWC conditions, was carried out using cuckoo search algorithm (CSA). The decay curves used in the modeling are the median (P50), 10th (P10), and 90th (P90) percentile decay curves of the RWC tracks, which constitute the top 2% longest lasting wakes. The fact that the correlation coefficient (R) values are very close to 1 for all datasets as a result of the error analysis shows that the prediction success of the CSA model is quite high.

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“…To the knowledge of the authors, there has not yet been a study that calculates the circulation strength of a leading multi-rotor wake vortices to study the effect on the following multi-rotor when encountering the wake vortices. For comparison, the circulation strength of wake vortices from large fixed-wing aircraft [18] and rotorcraft [19][20][21] have been characterized from numerous flight tests and the decay of the circulation strength over distance and time has been observed. The wake vortices from a leading aircraft can induce undesirable motion on fixed-wing aircraft [22] and rotorcraft [23,24], so understanding the decay rate of wake vortices helps to determine the minimum separation that must be maintained between aircraft to mitigate the hazard due to the wake vortices [25,26].…”

Section: Introductionmentioning

confidence: 99%

A Study on Circulation Strength Decay Over Time of Quadrotor Wake Using Large Eddy Simulation

Nathanael

Wang

Low

2022

AIAA SCITECH 2022 Forum

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As the use of multi-rotors is becoming common, understanding how the wake vortices develop and decay from a multi-rotor is important to reduce the effect of wake vortices on other multi-rotors and ensure their safety during operation by applying a wake separation minima. This paper proposes a method of flow simulation in ANSYS Fluent to study the decay of wake vortices from quadrotor propellers as the vortices evolve over distance and time. First, the near-field wake flow from the quadrotor propellers was simulated using Reynolds-Averaged Navier-Stokes (RANS) turbulence model. The velocity profile in the quadrotor frame of reference was then extracted to be applied for a flow simulation using Large Eddy Simulation (LES). The circulation strength as a function of distance could then be calculated, but it was limited by the length of the computational grid due to the wake flow being seen from the quadrotor frame of reference. To change into the stationary frame of reference, the interpolation data from the first stage LES was exported and modified by subtracting the freestream velocity from the velocity component in the freestream direction. The modified interpolation data was then used for the second stage LES, and the circulation strength in terms of time could be calculated from the resulting wake flow. Three cases of flow simulation are presented in this paper: first using 380-mm-diameter propellers based on the SUI Endurance quadrotor propellers with forward flight speed of 6 m/s, second using the 380-mm-diameter propellers with 12 m/s speed, and third using 240-mm-diameter propellers (similar to the propellers of DJI Phantom quadrotor) with 12 m/s speed. Findings regarding the decay of wake vortex from multi-rotor vehicles will help in determining the safe separation distance required to mitigate the hazards due to wake vortex encounters and ensure the safety of multi-rotor vehicles.

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Characterization of Aircraft Wake Vortex Circulation Decay in Reasonable Worst Case Conditions

Cited by 9 publications

References 5 publications

Plate lines to enhance wake vortex decay for reduced separations between landing aircraft

Plate lines to enhance wake vortex decay for reduced separations between landing aircraft

Characterization modeling of wake vortex circulation decay under reasonable worst case conditions with cuckoo search algorithm

A Study on Circulation Strength Decay Over Time of Quadrotor Wake Using Large Eddy Simulation

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