Vortex wakes of Aircrafts

Vortex wakes of Aircrafts
Author: A.S. Ginevsky
Publisher: Springer Science & Business Media
Total Pages: 166
Release: 2009-07-07
Genre: Mathematics
ISBN: 3642017606

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.

Vortex Wakes of Conventional Aircraft

Vortex Wakes of Conventional Aircraft
Author: Coleman duPont Donaldson
Publisher:
Total Pages: 92
Release: 1975
Genre: Turbulence
ISBN:

A review is made of the present state of our knowledge of the vortex wakes of conventional aircraft. Included are discussions of wake rollup, geometry, instability, and turbulent aging. In the light of these discussions, a brief review is made of the persistence of vortices in the atmosphere, and design techniques which might be used to minimize wake hazard are considered.

Aircraft Wake Turbulence and Its Detection

Aircraft Wake Turbulence and Its Detection
Author: John Olsen
Publisher: Springer Science & Business Media
Total Pages: 599
Release: 2012-12-06
Genre: Technology & Engineering
ISBN: 1468483463

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.

A Flight Evaluation of Methods for Predicting Vortex Wake Effects on Trailing Aircraft

A Flight Evaluation of Methods for Predicting Vortex Wake Effects on Trailing Aircraft
Author: Glenn H. Robinson
Publisher:
Total Pages: 68
Release: 1972
Genre: Eddies
ISBN:

The results of four current analytical methods for predicting wing vortex strength and decay rate are compared with the results of a flight investigation of the wake characteristics of several large jet transport aircraft. An empirical expression defining the strength and decay rate of wake vortices is developed that best represents most of the flight-test data. However, the expression is not applicable to small aircraft that would be immersed in the vortex wake of large aircraft.

Wake Turbulence

Wake Turbulence
Author: United States. Federal Aviation Administration
Publisher:
Total Pages: 20
Release: 1971
Genre: Turbulence
ISBN:

Wake Turbulence

Wake Turbulence
Author: National Research Council
Publisher: National Academies Press
Total Pages: 102
Release: 2008-04-27
Genre: Science
ISBN: 0309113792

Without major changes, the current air transportation system will be unable to accommodate the expected increase in demand by 2025. One proposal to address this problem is to use the Global Positioning System to enable aircraft to fly more closely spaced. This approach, however, might be limited by the wake turbulence problem, which can be a safety hazard when smaller aircraft follow relatively larger aircraft too closely. To examine how this potential hazard might be reduced, Congress in 2005 directed NASA to request a study from the NRC to assess the federal wake turbulence R&D program. This book provides a description of the problem, an assessment of the organizational challenges to addressing wake turbulence, an analysis of the technical challenges in wake turbulence, and a proposal for a wake turbulence program plan. A series of recommendations for addressing the wake turbulence challenge are also given.