Apparatus for accelerating destruction of a vortex formed by a wing of an aircraft

Abstract

An apparatus for accelerating a destruction of a vortex is formed at the rear of a wing of an aircraft by a merging of first and second co-rotating eddies. A perturbation device is disposed adjacent of an area of creation of the first co-rotating eddy. The device is configured to generate a periodic perturbation having a wavelength capable of exciting at least on instability mode of the first eddy.

Description

CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims priority under 35 U.S.C. § 119 to French Patent Application 01 02804, filed on Mar. 1, 2001, and under 35 U.S.C. § 120 to U.S. patent application Ser. No. 10 / 080,407 filed on Feb. 25, 2002, the disclosures of which are incorporated by reference herein in their entirety.FIELD OF THE INVENTION [0002] The present invention relates to a process and device for accelerating the destruction of at least two vortices in the wake of a moving body. [0003] The present invention is applied more particularly, but not exclusively, to an aircraft, especially a transport aircraft. [0004] In this case, the two (or more) vortices to which the present invention is applied are generally created when the aircraft is taking off or landing, and at least one flap, particularly a wing flap, is deployed on each wing of the aircraft. These two vortices are contra-rotating and one of them is created in each of the two wakes of the said wings ...

AI Technical Summary

Benefits of technology

[0016] For this purpose, the said process for accelerating the destruction of a pair of contra-rotating vortices which are created in the wake of a moving body having at least two wings, where each wing has at least two lifting surfaces, and which are separated from each other by an inter-vortex distance, each of the said contra-rotating vortices being formed at the rear of the corresponding wing by the merging of at least two co-rotating eddies which are created by the arrangement of the said lifting surfaces of the wing, each of the said co-rotating eddies having a plurality of core instability modes, is characterized in that a periodic perturbation of the flow is generated on each of the said wings, in the vicinity of the area of creation of at least one of the said co-rotating eddies associated with the wing, and in that each of the said periodic perturbations has a wavelength capable of exciting at least one of the said instability modes of the corresponding eddy in such a way as to increase the core of the contra-rotating vortex which is created by the unstable merging of this eddy with the other eddy, so that the diameter of the said core becomes greater than a predetermined proportion of the said inter-vortex distance.

[0017] Thus, owing to the periodic perturbations generated according to the present invention, the ratios between the core diameters of the two vortices on the one hand, and the inter-vortex distance on the other hand, become greater than a predetermined critical value, above which the two vortices begin to interact strongly and are rapidly destroyed. This is because, as mentioned above, when this critical value is reached there is an exchange of fluid between the two contra-rotating vortices, with the creation of smaller secondary eddies, which are perpendicular to the axes of the said vortices. This exchange of fluid causes a rapid and marked decrease in the circulation in each vortex, and consequently the disintegration or destruction of the said pair of contra-rotating vortices.

[0018] The process according to the present invention therefore makes it possible to reduce the duration of the said contra-rotating vortices and thus overcome the aforesaid drawbacks.

[0025] According to the invention, the said device is characterized in that it comprises, on each of the said wings, at least one perturbation means which is positioned in the vicinity of the area of creation of one of the said co-rotating eddies associated with the wing, and in that each of the said perturbation means can generate a periodic perturbation of the flow, which has a wavelength capable of exciting at least one of the said instability modes of the corresponding eddies in such a way as to increase the core of the contra-rotating vortex which is created by the merging of this eddy with the other co-rotating eddy in such a way that the diameter of the said core becomes greater than a predetermined proportion of the said inter-vortex distance.

[0030] Additionally, at least one of the said perturbation means is advantageously retractable. For this purpose, the said perturbation means is preferably retractable into the wing or into fairings fitted on the wing (the strut end fairing, for example) or into the flap. This avoids increasing the drag and thus avoids degrading the performance of the moving body, particularly in the absence of contra-rotating vortices, especially in cruising flight in the case of an aircraft.

Problems solved by technology

This exchange of fluid causes a rapid and marked decrease in the circulation in each vortex, and consequently the disintegration or destruction of the said pair of contra-rotating vortices.

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