The invention relates to a method and to a device for producing riblets (1), the riblets (1) being introduced by means of laser interference structuring or DLIPdirect laser interference patterningin particular into an already coated and cured surface. The invention further relates to a component having the riblets produced in this way. Aircraft, ships, and wind turbines can be operated with lower drag in this way.

This patent provides for a method and apparatus 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 method and apparatus 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 coating apparatus for the reduction of aerodynamic noise and vibrations. The coating apparatus is configured to include a group of fibrillar structures, wherein each fibrillar structure is configured with a diverging tip so that the coating reduces the size of and shifts downstream, a separation bubble, and modulates large-scale recirculating motion. Each fibrillar structure can be configured as a cylindrical micropillar. The group of fibrillar structures can be configured as a group of uniformly distributed cylindrical micropillars (e.g., one or more micropillar arrays). The surface coating is effective in reducing the separation bubble and displacing the separation bubble downstream. The coating facilitates a reduction in noise (e.g., aerodynamic noise) and vibrations due to the reduction in the size of the separation bubble.

Thermally stable microstructured layers comprising polyurethane, polyurea and/or polyurethane/urea semi-IPN materials are provided which have microstructured surfaces which are highly durable, erosion resistant, and thermally stable. The microstructured layer comprises a semi-IPN of a polymer network selected from the group consisting of urethane acrylate polymer networks, urethane/urea acrylate polymer networks and urea acrylate polymer networks and a linear or branched polymer that is a thermoplastic polymer selected from the group consisting of thermoplastic polyurethanes, thermoplastic polyurethane/polyureas, thermoplastic polyureas, and combinations thereof. The microstructures are thermally stable at temperatures above the crossover point of the thermoplastic polymer, despite comprising a majority of such thermoplastic material. In another aspect, the present disclosure provides methods of making microstructured layers according to the present disclosure.

A system and method for preparing a fluid flow surface may include the steps of: (1) producing a laser beam, (2) moving the laser beam across a surface of a work piece, and (3) machining a riblet in the surface by removing material from the surface, wherein the riblet includes a pair of ridges, wherein the pair of ridges is approximately parallel to each other, and each one of the ridges includes opposed sides, and a groove formed between facing ones of the sides and separating the ridges.

A strake may comprise a plate, wherein the plate extends between a forward end and an aft end along a first direction and the plate extends between a root end and a tip end along a second direction, a first tab extending from the root end of the plate, wherein a first fastening aperture is disposed in the first tab, and a second tab extending from the root end of the plate, wherein a second fastening aperture is disposed in the second tab.

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.

An improved aircraft system is provided. The improved aircraft system comprises an adjustable vortices device that may be attached to an aircraft to create various vortices effects, which increase take-off weight and improve low-speed handling of the aircraft. The adjustable vortices device comprises a linear actuator, a pivot mechanism, and a vortex generator. The pivot mechanism is operably connected to the linear actuator in a way such that the translational energy of the linear actuator causes the pivot mechanism to rotate about a central axis. The vortex generator is moveably attached to a surface of the aircraft and coupled to the pivot mechanism in a way such that rotating the pivot mechanism causes the vortex generator to rotate about a central axis, which alters the angle the vortex generators move through the air.

A mould for obtaining an element is provided. The mould includes an outer face and a plurality of parallel ribs and/or grooves formed on the outer face. One of the walls of the mould includes ribs and/or grooves of which at least a portion of the ribs and/or grooves can be retracted, at least temporarily, such that at least a portion of the surface of the wall is smooth.

A blade for a wind turbine having an airfoil with a thickness of at least 20% and in particular at least 25% including a vortex generator pair between chord wise position 20% c and 70% c, the vortex generator pair including 2 not directly connected fins and a base which interconnects the fins and where the fins are placed under opposite angles of attack. The fins are cambered by at least 1% in particular by at least 2% and more particularly by a least 3% of the fin chord. According to an embodiment the base of the vortex generator pair is W-shaped, the fins of a pair are designed to generate contra rotating vortices and the distance between the suction sides of the fins is approximately 150% of that between the pressure sides and the trailing part of the fins is rounded so that non-concentrated vortices are generated.