Final Report Summary - FAR-Wake (Fundamental Research on Aircraft Wake Phenomena) The 'Fundamental research on aircraft wake phenomena' (FAR-WAKE) project was 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 safety and capacity of air transport. The project focused 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. 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 provided the synthesis and assessment. In the majority of cases, emphasis was put on the study of simplified geometries and generic vortex configurations, which facilitates the use of different complementary approaches. In support of new experimental and numerical investigations, theoretical/analytical treatment was 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 data bases. The confrontation and comparison of different sets of results validate the findings and make the description of the studied phenomena more complete. At the end, an effort was made to provide a synthesis of all the new fundamental results that were 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. 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. Related documents Final Report - FAR-Wake (Fundamental Research on Aircraft Wake Phenomena)
