Provided is a filtering apparatus configured to interact with objects of interest within a medium. The properties of the filtering apparatus can be configured to modify the trajectory of individual objects of interest which interact with the filtering apparatus within several orders of magnitude of the mean free path of objects of interest. Surfaces of a filtering apparatus can be constructed to preferentially redirect objects of interest in a desired direction, such as a direction substantially parallel to a surface, or substantially along the length of a channel connecting two reservoirs. This can modify the net diffusion of objects of interest relative to the surface, which can modify the bulk fluid flow velocity magnitude along the surface. This can be employed to reduce the viscous drag on a surface moving relative to a fluid, or to generate thrust, or to convert thermal energy of a fluid into useful work.

A riblet film for reducing the air resistance of aircraft, comprising a suspension with magnetic particles enclosed therein. Depending on the pattern of a magnetic field acting on the riblet film, the magnetic field that is acting can be made visible, at least in certain regions, by changing the orientation of the magnetic particles. The riblet film allows an inspection of the aircraft structure located under the riblet film through the riblet film.

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 irregular surface texture fabricated on a body which travels through fluid in order to reduce the flow drag incurred by the body moving relative to the fluid. The dominate orientation of the irregular surface texture runs in the longitudinal direction, however, ridge and valley structures may occur in any orientation so that the resulting texture mimic the turbulence characteristic present in the surrounding flow field.

The present invention relates to structured, gas-holding surfaces for improving the friction-reducing properties of gas layers held under a liquid and for the simultaneous suppression of turbulence. The present invention furthermore relates to a device comprising this structured, gas-holding surface and to the use of this structured, gas-holding surface.

An airflow profiled structure having a profiled leading edge. The profiled leading edge having, along a leading edge line, a serrated profile line with a succession of teeth and depressions. The airflow profiled structure also includes a porous acoustically absorbent region located towards the bottom of the depressions.

The present invention provides a riblet structure that further reduces drag, which is a sum of turbulent friction drag and pressure drag, and an object including such a riblet structure. An object such as an aircraft, plant, and pipeline includes a wavelike riblet pattern on a surface. The wavelike riblet pattern includes a large number of wavelike riblets. Each of the large number of wave riblets includes a wavelike ridge line, and a height thereof changes cyclically with respect to a fluid flow direction. With such a configuration, drag, which is a sum of turbulent friction drag and pressure drag, can be further reduced.

A front fan turbomachine comprising an annular separating wall (160) having a slat (16) for separating an air flow between a primary flow and a secondary flow, the slat having a leading edge; IGV blades for guiding the primary flow and OGV blades for guiding the secondary flow.

The leading edge of the slat (16) has a serrated profile (28) having a succession of teeth and depressions.

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.

A flow balancer to reduce turbulence and achieve a laminar water flow system for fish while being pumped. The flow balancer having a tubular guide for the fish made from spaced apart blades having a width greater than a thickness of the spaced blades forming the tubular guide. The tubular guide is constructed and arranged to prevent turbulent and non-parallel water flow and allow fish to pass in a laminar water flow.