A flow interrupting device may cause a flow to separate from a wingtip device at a desired angle of attack. The flow interrupting device may be coupled to a leading edge of a wingtip device where a flow disruptor may be configured to alleviate a load on the wingtip device. The flow disrupter may comprise an edge that extends into a boundary layer at a threshold angle of attack that may disrupt the boundary layer and cause a flow to separate from the wingtip device. This separated flow may reduce stresses experienced by the wingtip device and wing during various flight conditions where a transverse flow is encountered.

A rotor blade of an aerodynamic rotor of a wind turbine, comprising: at least a first and a second wing fence, with the first wing fence being arranged at the rotor blade in radial direction, in relation to an axis of rotation of the rotor, in a range between 25% and 40%, and the second wing fence being arranged at the rotor blade in radial direction, in relation to an axis of rotation of the rotor, in a range between 45% and 60%.

Krueger flap apparatus and methods incorporating a bullnose having a contour variation along a spanwise direction are described. An example apparatus includes a Krueger flap having a bullnose extending in a spanwise direction. The bullnose includes a contour variation formed by a plurality of protuberances located along the bullnose. Respective ones of the protuberances are spaced along the spanwise direction.

Aerofoil accessories are provided, configured for selective attachment to a wing element, the wing element having an outer facing aerofoil surface and being based on at least one datum aerofoil section. Each accessory provides a modified geometric profile to a datum profile of the at least one aerofoil section when attached to the wing element. The accessories are each configured for having a substantially fixed geometric profile with respect to the at least one datum aerofoil section at least whenever said wing element is airborne with the respective accessory attached to the wing element. The modified geometric profile is such as to provide said wing element with the accessory attached thereto with a desired change in performance relative to a datum performance provided by the wing element absent the accessory. A kit is also provided for enhancing performance of a wing element in off-design conditions. A method is also provided for enhancing performance of a wing element in adverse conditions.

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.

A body adapted for relative movement with respect to a fluid, said movement creating a flow of fluid with respect to the body in a relative flow direction, said body having at least one surface with a surface profile exposed to the fluid and comprising at least one smooth step facing in relative flow direction towards the flow, said step having a height between 4% and 30% of the local boundary layer thickness (.sub.99) of the fluid contacting the body in the vicinity of the step.

An airfoil body may include a plurality of tubercles along a leading edge of the airfoil body and a plurality of crenulations along a trailing edge of the airfoil body, wherein at least one of a position, a size, and a shape of the plurality of tubercles and the plurality of crenulations varies in a non-periodic fashion. The non-periodic fashion may be according to a Fibonacci function and may mimic the configuration of a pectoral fin of a humpback whale. The tubercles and crenulations may be defined with respect to a pivot point. The spanwise profile, including the max chord trailing edge curvature, may closely follow divine spirals and related Fibonacci proportions. The spanwise chord thickness may vary in a nonlinear pattern. Related methods are also described.

An aerodynamic structure comprising a shock bump (3) extending from its surface. The shock bump is asymmetrical about a plane of asymmetry, and the plane of asymmetry: passes through a centre (6) of the shock bump, is parallel with a principal direction of air flow over the structure, and extends at a right angle to the surface of the structure.

A combination comprises an aircraft wing trailing edge section and an adjustment body. The adjustment body comprises a tapered cross section in a local chord axis direction of the wing trailing edge section, a lower adjustment body surface connected to a top surface of the aircraft wing trailing edge section and a back-end surface having a height. The adjustment body is positioned such that the back-end surface is flush with the trailing edge of the aircraft wing trailing edge section. Attaching the adjustment body onto a top surface of the wing trailing edge section leads to compensation of an offset rolling moment due to unavoidable structural shape deviations of the aircraft and eliminates additional structural reinforcement requirements on the trailing edge compared to edge wedges mounted on the bottom surface of trailing edges. The trailing edge section may comprise a flap.

Thermal actuation of riblets is described herein. One disclosed example apparatus includes a riblet defining an aerodynamic surface of a vehicle. The disclosed example apparatus also includes a thermal expansion element within or operatively coupled to the riblet, wherein the thermal expansion element changes shape in response to a surrounding temperature, to displace a movable portion of the riblet relative to the aerodynamic surface to alter an aerodynamic characteristic of the vehicle.