A Technique for Simulating the Motion and Ground Effect of Aircraft Wake Vortices PDF Download

Author: R. H. Wickens
Publisher:
ISBN:
Category : Aerial spraying and dusting in agriculture
Languages : en
Pages : 26

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Author: A.S. Ginevsky
Publisher: Springer Science & Business Media
ISBN: 3642017606
Category : Mathematics
Languages : en
Pages : 166

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Investigation of vortex wakes behind various aircraft, especially behind wide bodied and heavy cargo ones, is of both scientific and practical in terest. The vortex wakes shed from the wing’s trailing edge are long lived and attenuate only atdistances of10–12kmbehindthe wake generating aircraft. The encounter of other aircraft with the vortex wake of a heavy aircraft is open to catastrophic hazards. For example, air refueling is adangerous operationpartly due to thepossibility of the receiver aircraft’s encountering the trailing wake of the tanker aircraft. It is very important to know the behavior of vortex wakes of aircraft during theirtakeoff andlanding operations whenthe wakes canpropagate over the airport’s ground surface and be a serious hazard to other depart ing or arriving aircraft. This knowledge can help in enhancing safety of aircraft’s movements in the terminal areas of congested airports where the threat of vortex encounters limits passenger throughput. Theoreticalinvestigations of aircraft vortex wakes arebeingintensively performedinthe major aviationnations.Usedforthispurpose are various methods for mathematical modeling of turbulent flows: direct numerical simulation based on the Navier–Stokes equations, large eddy simulation using the Navier–Stokes equations in combination with subrigid scale modeling, simulation based on the Reynolds equations closed with a differential turbulence model. These approaches are widely used in works of Russian and other countries’ scientists. It should be emphasized that the experiments in wind tunnels and studies of natural vortex wakes behind heavy and light aircraft in flight experiments are equally important.

Author: James N. Hallock
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 396

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 60

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Author: United States. Federal Aviation Administration
Publisher:
ISBN:
Category : Turbulence
Languages : en
Pages : 20

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Author: National Aeronautics and Space Administration
Publisher:
ISBN: 9781726156936
Category :
Languages : en
Pages : 40

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A study was conducted using strip theory to systematically investigate the effects of progressively more complete descriptions of the interaction of an airplane with a wake vortex system. The emphasis was in roll-dominant, parallel, vortex encounters. That is, the simulated airplane's longitudinal axis was nearly parallel to the rotation axis of the vortex system for most of the results presented. The study began with a drag-less rectangular wing in the flow field of a single vortex and progressed to a complete airplane with aerodynamic surfaces possessing taper, sweep, dihedral, and stalling and immersed in the flow field of a vortex pair in ground effect. The effects of the pitch, roll, and yaw attitudes of the airplane on the calculated accelerations were also investigated. The airplane had the nominal characteristics of a Boeing 757, and the vortex flow field had the nominal characteristics of the wake of a Boeing 767. The Bumham-Hallock model of a vortex flow field was used throughout the study. The data are presented mainly in terms of contours of equal acceleration in a two-dimensional area centered on the vortex pair and having dimensions of 300 feet by 300 feet.Stewart, Eric C.Langley Research CenterAERODYNAMICS; FLOW DISTRIBUTION; RECTANGULAR WINGS; ROLL; ROTATION; VORTICES; YAW; AIRCRAFT WAKES; MATHEMATICAL MODELS; BOEING 757 AIRCRAFT; BOEING 767 AIRCRAFT; GROUND EFFECT (AERODYNAMICS)...

Author: John Olsen
Publisher: Springer Science & Business Media
ISBN: 1468483463
Category : Technology & Engineering
Languages : en
Pages : 599

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The combination of increasing airport congestion and the ad vent of large transports has caused increased interest in aircraft wake turbulence. A quantitative understanding of the interaction between an aircraft and the vortex wake of a preceding aircraft is necessary for planning future high density air traffic patterns and control systems. The nature of the interaction depends on both the characteristics of the following aircraft and the characteristics of the wake. Some of the questions to be answered are: What deter mines the full characteristics of the vortex wake? What properties of the following aircraft are important? What is the role of pilot response? How are the wake characteristics related to the genera ting aircraft parameters? How does the wake disintegrate and where? Many of these questions were addressed at this first Aircraft Wake Turbulence Symposium sponsored by the Air Force Office of Sci entific Research and The Boeing Company. Workers engaged in aero dynamic research, airport operations, and instrument development came from several count ries to present their results and exchange information. The new results from the meeting provide a current picture of the state of the knowledge on vortex wakes and their interactions with other aircraft. Phenomena previously regarded as mere curiosities have emerged as important tools for understanding or controlling vortex wakes. The new types of instability occurring within the wake may one day be used for promoting early dis integration of the hazardous twin vortex structure.

Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 700

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Author: Daniel Guy Schauerhamer
Publisher:
ISBN: 9780355763850
Category :
Languages : en
Pages :

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To better understand aircraft wake behavior with the goal to increase flight safety and airport capacity, the aircraft wake vortex lifecycle was simulated using computational fluid dynamics. Using a build-up approach, best practices for wing-tip vortex roll-up were developed starting with a simple inviscid vortex, and building up in complexity to a finite wing and full aircraft. Validation of the best practices was accomplished with comparisons to wind tunnel data. Best practices were then applied to the German Aerospace Center F11 wind tunnel model and the NASA Common Research Model with validation of results with wind tunnel measurements. Vortex sensitivity to aircraft configuration were explored by changing the details of the F11 model, and by adding a generic winglet to the Common Research Model. Results demonstrated that the wake vortex changed significantly with aircraft configuration. The wake of the Common Research Model was used to initialize two-dimensional evolution studies which propagated the wake system to 10 wing spans downstream. Best practices were developed to demonstrate low numerical error and the computational savings of using adaptive mesh refinement. Three-dimensional simulations were carried out with the Common Research Model to resolve 10 wing spans downstream, however with a coarser-than-desired mesh due to computational limitations. The solution was used to initialize three-dimensional decay simulations. A testbed case of wake vortex decay was used to develop best practices and quantify error sources for decay simulations in a cost-effective manner. Those best practices were applied to the Common Research Model decay simulation. Results throughout the research were compared to idealized vortex models that in practice are used to initialize decay simulations. For all comparisons, including the aircraft effects resulted with significant differences to the idealized vortex models. Including the aircraft effects in the simulations resulted in more accurate wake results.

Author: Eric C. Stewart
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 44

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