Overview
This project is the continuation of a recent effort, on a European level, to characterise, understand and control aircraft wake turbulence. Aircraft in flight leave behind large-scale swirling flows (vortices), which can represent a significant hazard to following aircraft, and therefore are of great importance for practical applications concerning air transport safety and capacity. The project focuses on unresolved fundamental aspects of wake dynamics, thus complementing the existing, mostly empirical knowledge obtained in previous projects.
The main objective was to gain new knowledge about open issues of vortex dynamics relevant to aircraft wakes, and to provide a more systematic description than previously achieved, of the phenomena involved in aircraft wake dynamics. These fundamental developments are necessary to achieve major advances in this domain, in view of a successful application of existing or future strategies for wake characterisation, prediction and alleviation. The topics include the precise role of vortex instabilities on wake decay, the influence of engine jets and fuselage wakes, and ground effects in wake evolution, relevant to the airport environment.
This project generated systematic results and physical understanding concerning previously unresolved issues related to aircraft trailing wakes, including the role of vortex instabilities, the influence of engine jets and fuselage wakes, and ground effects. This will create a solid knowledge base for future applications aiming at the reduction of wake turbulence hazards. Concerning ground effects, the project will in addition produce improved tools for the real-time prediction of wake vortex behaviour, to be used in the domain of Air Traffic Management.
The FAR-Wake project contained four major Work Packages. In the first, studies related to the dynamics and instabilities of one or several vortices were considered. The second Work Package introduced additional features: jets from engine exhaust, and wakes (axial velocity deficits) generated by the fuselage or other wing elements. The third Work Package considered wake evolution near the ground, with special emphasis on the prediction of wake behaviour in this situation. The fourth Work Package deals with synthesis and assessment.
In the majority of cases, emphasis was put on the study of simplified geometries and generic vortex configurations, which facilitated the use of different complementary approaches. In support of new experimental and numerical investigations, theoretical/analytical treatment is applied, with the aim of obtaining a systematic description and comprehension of the phenomena. Furthermore, extensive use was made of results and data from previous projects or available databases.
The confrontation and comparison of different sets of results would validate the findings and make the description of the studied phenomena more complete. At the end, an important effort was made to provide a synthesis of all the new fundamental results obtained, and to assess their relevance for the wake turbulence problem for real aircraft. Certain features found to be promising for the acceleration of wake decay, such as flows with multiple wake vortices, were analysed and tested in a realistic configuration, using numerical simulations and experiments in a large-scale towing tank facility.
Funding
Results
This project has generated systematic results and physical understanding concerning previously unresolved issues related to aircraft trailing wakes, including the role of vortex instabilities, the influence of engine jets and fuselage wakes, and ground effects. These results represent a solid knowledge base for future applications aiming at the reduction of wake turbulence hazards. Concerning ground effects, the project has in addition produced improved tools for the real-time prediction of wake vortex behaviour, for potential use in the domain of Air Traffic Management. Due to the mostly fundamental character of the research, the results are also relevant in various other areas of fluid mechanics.
Technical Implications
The FAR-Wake project has led to a large number of publications in refereed scientific journals and presentations/papers at international conferences.