A raised structure for reducing frictional drag due to viscosity of a flow toward an object in a direction forming an acute angle with an end portion of the object. The raised structure includes a plurality of raised bodies provided on a surface of the leading edge of the object at a downstream side of a stagnation point of the main flow, wherein a height of each raised body changes along a smooth convex curve, and the raised bodies are arranged in an array to form a first uneven shape changing periodically in a first cross section having a constant distance from the stagnation point and orthogonal to the surface, and a second uneven shape changing in a second cross section that is orthogonal to a line composed of the stagnation point and the first cross section, the second uneven shape having concave portions and convex portions that change periodically.

A laser processing device for generating a plurality of grooves in a surface comprises an optical diffraction arrangement adapted to receive a laser radiation and to generate an output radiation hereupon, the output radiation having a plurality of intensity maxima. An actuator arrangement is provided for generating a relative movement between the output radiation and the surface, wherein each intensity maximum generates a groove of the plurality of grooves.

A system for controlling turbulence of fluid flowing past a window includes an imaging device compartment defining an interior and an exterior separated by a window, wherein the window encloses at least a portion of the interior, wherein the exterior includes at least one turbulator on a side upstream of the window positioned to induce turbulence over the entirety of a boundary layer of the fluid flowing past the window for even heat transfer between the fluid and the window.

Part comprising a wall which comprises a first zone (541), a first zone (541) and the second zone (542), a network of riblets being formed on the first zone (541), the second zone (542) and also on the transition zone (54t) so as to reduce the drag of the part when a flow of air flows along said wall; the height, the width and the spacing of the riblets formed on the transition zone (54t) changing along said transition zone (54t) so as to pass from the height, width and spacing of the riblets formed on the first zone at a first end of the transition zone to the height, width and spacing of the riblets formed on the second zone (542) at a second end of the transition zone (54t), the transition zone (54t) comprising a central portion on which the riblets comprise on one hand the height and the width that are respectively equal to the height and width of the riblets on the first zone (541), and on the other hand a spacing equal to the spacing of the riblets of the second zone (542).

This relates to the field of aerohydrodynamics and can be used on wings and control surfaces of aircraft, controlled spoilers of sports cars, all-movable masts and sails of sailing yachts and sailboards, as well as on blades and vanes of various bladed machines. An aerohydrodynamic surface includes an array of vortex generators and a main part. The main part comprises two sides mating with each other to form a leading and a trailing edges. The array of vortex generators includes elevations with crescent-shaped working edges located near the leading edge. The elevations and the working edges are configured to generate counter-rotating vortex structures. An array of vortex generators and a method of mounting the same onto the aerohydrodynamic surface are also described. The invention makes it possible to improve the properties of the aerohydrodynamic surfaces at high angles of attack.

[Object] To provide a riblet structure that increases resistance reducing performance and is easily manufacturable, and an object including such a structure on a surface thereof. [Solving Means] This riblet structure includes a plurality of wave-shaped riblets on a surface thereof, in which each of the riblets has a smaller peak height as an angle formed between a ridge line and a fluid flow direction becomes larger, a width between peak bases in a direction orthogonal to the fluid flow direction becomes smaller as the angle becomes larger, and an angle formed between a slope of a peak of the riblet and the surface at the peak base or a curvature at the peak base is identical at any position in a cross-sectional shape in the direction orthogonal to the fluid direction.

A method applies aerodynamically functional film to a body around which complex flow occurs. The method includes: determining flow lines on a surface of the body for a predetermined surrounding flow state on a basis of a computer model of the body using a numerical flow simulation; developing at least one surface segment of the computer model provided with flow lines to form a two-dimensional surface; locating at least one coherent field in the developed surface segment having local flow directions readable at the flow lines in a predetermined angle range around a main flow direction of the respective field; and applying the aerodynamically functional film to the body within the field boundary of the at least one field located in the developed surface segment in such a way that the aerodynamically functional film is aligned along the main flow direction of the respective field.

Methods for forming microstructures in photocurable material are described. At least one image of light or radiation for curing the photocurable material is applied in a pattern corresponding to the image. The image is formed by near-field diffraction of the light or radiation and comprises areas of higher intensity adjacent to areas of lower intensity.

An exemplary aircraft includes a wing positioned below a vertical rotor, the wing extending to an outboard end, and an anhedral winglet extending from the outboard end through an angular transition to a tip, the anhedral winglet having an external surface exposed to the rotor downwash and the external surface is contoured to generate local wing lift in response to the rotor downwash.

An aircraft surface cover is provided. The aircraft surface cover includes a cover member that is configured to be removably secured to an aircraft structure. The cover member includes an exterior surface that has a microtextured surface including microtexture ribs that are configured to improve aerodynamic performance of the aircraft structure.