A structural component for a vehicle has a surface with a riblet structure. The riblet structure includes a plurality of grooves, including a first groove having a first longitudinal section forming a first angle with a main longitudinal direction of the structural component. The first angle is larger than 0 and the main longitudinal direction corresponds to a flow direction of a fluid along the surface of the structural component.

In one embodiment, an airfoil includes a first end and a second end opposite the first end. The airfoil also includes a first side and a second side opposite the first side. The airfoil includes a continuous panel coupled to the first side of the airfoil. The continuous panel includes a first edge having a first uneven edge pattern. The first edge has at least four vertices disposed thereon. The continuous panel extends from the first end of the airfoil to a second end of the airfoil.

The invention discloses a flight vehicle generating a lift from an interior thereof. The fluid channel inside the flight vehicle communicates with the engine and the ports on the upper surface of the outer shell. With the powerful suction of the engine, the fluid on the upper surface of the outer shell is quickly sucked into the fluid channel via respective ports under conditions of long path, large area, high speed and low air pressure, which results in large lift from the interior of the flight vehicle. In the course of generating the lift, the fluid resistances of the fluid wall and the fluid hole are sucked into the fluid channel through the ports at the front and the surrounding area of the flight vehicle, then high-speed fluid is emitted from the rear port. This approach contributes greatly to the transformation of the existing flight vehicle. The present invention significantly improves the lift, the speed and the carrying capacity of the existing flight vehicle with lowered energy consumption.

Airfoil and hydrofoils systems with structures having a surface texture defined by fractal geometries are described. Raised portions or fractal bumps can be included on the surfaces, forming a surface texture. The surface textures can be defined by two-dimensional fractal shapes, partial two-dimensional fractal shapes, non-contiguous fractal shapes, three-dimensional fractal objects, and partial three-dimensional fractal objects. The surfaces can include indents having fractal geometries. The indents can have varying depths and can be bordered by other indents, or bumps, or smooth portions of the airfoil or hydrofoil structure. The fractal surface textures can reduce vortices inherent from airfoil and hydrofoil structures. The roughness and distribution of the fractal surface textures reduce the vortices, improving laminar flow characteristics and at the same time reducing drag. The systems are passive and do not require applied power.

An aerodynamic element is provided with at least one set of protruding elements, each of the protruding elements is produced in the form of an elongate and profiled rib projecting from a surface of the aerodynamic element. The protruding elements are arranged at the surface of the aerodynamic element, one beside the other, being oriented substantially parallel to one another so that each of them generates a vortex, the set of vortices thus generated making it possible to reduce crossflow instability.

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed are systems, methods, and apparatus for actively adjusting the position of one or more propeller blade treatments of a propeller blade of an aerial vehicle during operation of the aerial vehicle. For example, the propeller blade may have one or more propeller blade treatments that may be adjusted between two or more positions. Based on the position of the propeller blade treatments, the airflow over the propeller is altered, thereby altering the sound generated by the propeller when rotating. By altering the propeller blade treatments on multiple propeller blades of the aerial vehicle, the different sounds generated by the different propeller blades may effectively cancel, reduce, and/or otherwise alter the total sound generated by the aerial vehicle.

An engine nacelle is provided for an aircraft. The engine nacelle comprises: an inlet for receiving an air flow to generate a thrust force for the aircraft; a lip portion positioned at the inlet and surrounding the inlet; and at least one strake provided on a surface of the engine nacelle.

Provided are aerodynamic articles and related methods that use an aerodynamic body with a microstructured surface thereon. The microstructured surface has a plurality of parallel primary ridges defining major capillary channels, and optionally a plurality of parallel secondary ridges having a height less than that of the primary ridges and extending between and generally parallel to the primary ridges. The optional secondary ridges at least partially define two or more minor capillary channels within each major capillary channel. The aerodynamic surface provides reduced drag and is capable providing a high degree of friction against shoe surfaces under oil and water contaminated conditions.

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.

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).