An aerodynamic or hydrodynamic wall surface has an array of fibrillar structures disposed on and extending from the wall surface, wherein each fibrillar structure comprises a stalk and a tip. The stalk has a first end and a second end, wherein the first end is attached to the wall surface, and the stalk is oriented with respect to the wall surface at a stalk angle between approximately 1 degrees and 179 degrees. The tip has a first side and a second side, wherein the first side is attached proximate to the second end of the stalk, the tip has a larger cross-sectional area than the stalk, and the second side comprises a substantially planar surface that is oriented with respect to the stalk at a tip angle between approximately 0 degrees and 90 degrees.

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.

A self-cleaning external with a self-cleaning aerodynamic surface configured to extract at least some of the oxygen present in the atmosphere in contact with the aerodynamic surface so as to at least partially deprive a haemolymph of the insect residue, present on the aerodynamic surface after being hit by insects, of oxygen. Also, a vehicle with at least one such self-cleaning aerodynamic surface.

This disclosure relates to a method and resulting apparatus of applying a riblet sheet comprising a riblet film layer and a riblet liner layer on an airfoil surface. The method comprises applying the riblet film layer of the riblet sheet over the airfoil surface, peeling back at least a portion of the riblet liner layer from the riblet film layer to expose a portion of the riblet film layer, applying a attaching hardware or a non-textured surface film over at least a portion the riblet film layer portion; and applying the peeled back portion of the riblet liner layer over a portion of the attaching hardware.

A method and system delay the laminar-to-turbulent transition of a supersonic or hypersonic boundary layer flow moving in a flow direction over a surface. For supersonic boundary layer flow, oblique first-mode instability waves present in the boundary layer and propagating at an oblique angle relative to the flow direction cause a laminar-to-turbulent transition in the boundary layer flow. These instability waves have a wavelength associated therewith in a direction perpendicular to the flow direction. Flow disruptors are used to generate modulations within the boundary layer flow wherein a wavelength of the modulations along the direction perpendicular to the flow direction is less than one-half of the wavelength of the instability waves. For hypersonic boundary layer flow, the flow disruptors generate modulations within the boundary layer flow wherein the wavelength of the modulations is less than streak spacing for optimal transient growth or, equivalently, in the range of one to two times the boundary layer thickness.

A method of micro-texturing a surface is disclosed. The method includes printing an etchant onto a substrate surface and forming a micro-texture on the substrate surface by removing material from the substrate surface.

A method of micro-texturing a substrate surface is disclosed, including printing a maskant on the substrate surface to define exposed surface zones on the substrate surface. The method further includes forming a micro-texture on the substrate surface by removing material from the exposed surface zones, and removing the maskant from the substrate surface.

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.

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.

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.