An apparatus is for attaching an aerodynamically functional film to a surface of a body around which flow passes. The apparatus includes: a self-adhesive, redetachable positioning film having positioning aids for the exact positioning of the positioning film on the surface of the body around which flow passes and having at least one application area for the aerodynamically functional film that is to be applied.

Multilayer riblet applique and methods of producing the same are described herein. One disclosed example method includes applying a first high elongation polymer material to a web tool, where the web tool is to be provided from a first roll, and heating, via a first heating process, the first high elongation polymer material. The disclosed example method also includes applying a second high elongation polymer material to the first high elongation polymer material, and heating, via a second heating process, the second high elongation polymer material. The disclosed example method also includes applying, via a laminating roller, a support layer to the second high elongation polymer material.

A contamination protection is for edges of a riblet film, which is adhesively bonded to a surface. The riblet film has riblets formed on an upper side of a film layer, and an adhesive layer at a lower side of the film layer. The contamination protection has: an edge protection. The edge protection is formed directly on the riblet film that is adhesively bonded to the surface in such a manner that the edge protection covers the adhesive layer of the riblet film, but does not protrude over the upper side of the riblet film.

A method for producing an object with riblets on and/or in the surface, around which object a fluid flows during use. A frictional resistance acting on a surface region along a flow direction during a flow around the object in the fluid is calculated and added up to a cumulative frictional resistance over a length of the surface region in the flow direction, after which the riblets are provided on and/or in a partial region of the surface in which an increase in the cumulative frictional resistance is at least 0.9, in particular greater than 1.0 to 0.9. Moreover, a method is provided for modifying a surface of an object around which a fluid flows during use, such as a foil. A structure having riblets is created on and/or in the surface, which structure reduces flow resistance of the object. Furthermore, a fluid flows around an object during use.

A wind turbine includes a blade having a leading edge, a trailing edge, and opposing first and second surfaces extending between the edges. A vortex generator pair includes a base attached to the first surface and first and second spaced apart fins extending outwardly from opposing portions of the base. The fins each have a leading edge, a trailing edge, a suction side and a pressure side. Each of the suction sides have a trailing half and a leading half.

In one embodiment, a method for reducing drag includes forming a smooth surface on a first portion of a physical object. The method also includes forming periodic riblets on a second portion of the physical object. The method further includes generating a flow over the periodic riblets of the second portion of the physical object and over the smooth surface of the first portion of the physical object. The second portion of the physical object is adjacent to the first portion of the physical object. Each peak of each riblet of the periodic riblets of the second portion of the physical object is located above a plane of the smooth surface of the first portion of the physical object. Each valley between adjacent riblets of the periodic riblets of the second portion of the physical object is located below the plane of the smooth surface of the first portion of the physical object. A length of each riblet of the periodic riblets runs parallel to a direction of the flow.

A linear step discontinuity on the lower surface of the lifting surface is disclosed extending from the front of the lifting surface, possibly the leading edge, and may extend in the direction of the line of flight towards the trailing edge. The linear step discontinuity represents a step up if moving from the outboard end to the inboard end, such that in use fluid moving over the lifting surface tumbles over the linear step discontinuity to create a vortex in the fluid passing over the upper surface. The lifting surface may be an aircraft wing or in particular a winglet on an aircraft wing. The linear step discontinuity may be provided by the straight edge of a semi-circular object integrated into or adhered to the surface of the lifting surface.

Disclosed are methods and apparatuses for mitigating the formation of concentrated wake vortex structures generated from lifting or thrust-generating bodies and maneuvering control surfaces wherein the use of contour surface geometries promotes vortex-mixing of high and low flow fluids. The methods and apparatuses can be combined with various drag reduction techniques, such as the use of riblets of various types and/or compliant surfaces (passive and active). Such combinations form unique structures for various fluid dynamic control applications to suppress transiently growing forms of boundary layer disturbances in a manner that significantly improves performance and has improved control dynamics.

A tracking wedge, a rotor and a method for modifying a movement of air over a tracking wedge. According to aspects of the disclosure, a tracking wedge used to correct the tracking of a helicopter rotor blade may include one or more acoustic management mechanisms. The acoustic management mechanisms may change the manner in which air moves over the surface of the tracking wedge. In some examples, changing the manner in which air moves over the surface of the tracking wedge may reduce noise generated by the use of the tracking wedge.

According to one embodiment, a method of dispersing nanoparticles into a destination material includes providing a plurality of nanoparticles suspended in a carrier, adding a solvent to the plurality of nanoparticles suspended in a carrier, removing at least some of the carrier to yield the plurality of nanoparticles suspended in the solvent, mixing the nanoparticles suspended in the solvent with a destination material, and removing at least some of the solvent from the mixture of nanoparticles suspended in the solvent and the destination material.