An airflow profile structure having a leading and/or trailing edge profiled with a serrated profile having a succession of teeth and depressions. Along the leading and/or trailing edge, from a first location to a second location, the teeth of the serrated profile are individually inclined towards the second location.

A vortex suppression device (10) for a fluid flowing along a pathway (A-E), including: an elongate body with an outer surface having an elongate leading section and an elongate trailing section along the length of the elongate body, in relation to a direction of fluid flow (A-E) when the device is located in the pathway, the elongate body having at least one channel (24a-24d, 26a, 26b) which extends from the elongate leading section to the elongate trailing section of the elongate body, the channel (24a-24d, 26a, 26b) being configured so that in use, when the device is in the pathway, the channel (24a-24d, 26a, 26b) allows fluid flow (J) towards the trailing section that disrupts the formation of vortices (D).

A front fan turbomachine includes an annular separating wall having a slat for separating an air flow between a primary flow and a secondary flow, the slat having a leading edge; inlet guide vanes (IGV) for guiding the primary flow and outlet guide vanes (OGV) blades for guiding the secondary flow. The leading edge of the slat has a serrated profile having a succession of teeth and depressions.

In one embodiment, a method for reducing drag includes forming a smooth surface on a first portion of a physical object. The method also includes forming periodic riblets on a second portion of the physical object. The method further includes generating a flow over the periodic riblets of the second portion of the physical object and over the smooth surface of the first portion of the physical object. The second portion of the physical object is adjacent to the first portion of the physical object. Each peak of each riblet of the periodic riblets of the second portion of the physical object is located above a plane of the smooth surface of the first portion of the physical object. Each valley between adjacent riblets of the periodic riblets of the second portion of the physical object is located below the plane of the smooth surface of the first portion of the physical object. A length of each riblet of the periodic riblets runs parallel to a direction of the flow.

An airflow profile structure having a leading and/or trailing edge profiled with a serrated profile. The serrated profile has a succession of teeth and depressions, characterized in that, along the leading and/or trailing edge, from a first location to a second location, the teeth of the serrated profile are individually inclined towards the second location.

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.

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.

A component stage for a turbomachine includes a component section. The component section includes a flowpath surface at least partially exposed to a core air flowpath defined by the turbomachine, when the component stage is installed in the turbomachine. The component further includes a plurality of sequentially arranged riblets on the flowpath surface, the plurality of sequentially arranged riblets customized for an anticipated location of the flowpath surface within the turbomachine by defining one or both of a non-uniform geometry or a non-uniform spacing.

A novel mechanism for reducing boundary layer friction and inhibiting the effects of uncontrolled fluid turbulence and turbulent layer separation, thus reducing the body drag, kinetic energy losses and lowering engine and pump fuel consumption is proposed. It steps on the type of turbulence observed in the so-called in fluid dynamics “drag crisis”. Plurality of device shapes and plurality of devices producing the wanted pure form of even plurality of counter-rotating vortices extending into the flow, i.e. tubes, are presented and discussed in detail, contrasting with the prior art. Configurations of multiple devices for the purposes of drag and fuel reduction, including their simulations and experimental results are put forward. Additional embodiments of the resulting tubes disclose use on aircraft or vessel control surfaces as stall inhibitors, use in wind turbines as dynamic range extenders, as well as use in turbines in efficient cooling mechanisms.

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.