The present invention relates to a surface cover for a body which can be brought into contact with a liquid, comprising: a layer which at least partly contains gas and which is designed and arranged such that at least some sections of a layer face facing the liquid contacts the liquid; a gas-permeable layer which is arranged on the gas-containing layer on a face that faces the body and is opposite the face facing the liquid or which is integrally formed with the gas-containing layer; and a gas-supplying device which is connected to the gas-permeable layer such that gas can flow from the gas-supplying device to the gas-containing layer through the gas-permeable layer. The invention also relates to an arrangement and a use.

An airflow adjusting apparatus to be installed in a vehicle includes two or more outward airflow generators and a controller. The outward airflow generators are disposed side by side in a vehicle front-rear direction in vicinity of an outer edge in a vehicle widthwise direction on an upper surface of a vehicle body on a front side of a windshield. The outward airflow generators are each configured to form an outward airflow with respect to the vehicle body. The outward airflow flows in a direction that is toward an outer side in the vehicle widthwise direction and toward a rear side of the vehicle. The controller is configured to control the outward airflow generators.

A propulsion system coupled to a vehicle. The system includes a diffusing structure and a conduit portion configured to introduce to the diffusing structure through a passage a primary fluid produced by the vehicle. The passage is defined by a wall, and the diffusing structure comprises a terminal end configured to provide egress from the system for the introduced primary fluid. A constricting element is disposed adjacent the wall. An actuating apparatus is coupled to the constricting element and is configured to urge the constricting element toward the wall, thereby reducing the cross-sectional area of the passage.

A vortex breaker assembly includes a vessel, a first conduit, and a fluid source. The vessel having a first fluid arranged therein. The vessel includes an opening formed in an outer wall. The first conduit is coupled to the vessel and configured to open into the vessel via the opening such that the first fluid can flow into the first conduit via the opening. The first conduit includes an inlet formed therein. The fluid source provides a second fluid to the at least one inlet. The second fluid flows into the first conduit from the inlet at a predetermined flow momentum such that the second fluid interacts with the first fluid flowing from the vessel and through the first conduit so as to disrupt a flow field of the first fluid and minimize formation of a fluidic vortex of the first fluid at the opening.

Systems and methods are described herein to implement transverse momentum injection at low frequencies to directly modify large-scale eddies in a turbulent boundary layer on a surface of an object. A set of transverse momentum injection actuators may be positioned on the surface of the object to affect large-scale eddies in the turbulent boundary layer. The system may include a controller to selectively actuate the transverse momentum injection actuators with an actuation pattern to affect the large-scale eddies to modify the drag of the fluid flow on the surface. In various embodiments, the transverse momentum injection actuators may be operated at frequencies less than 10,000 Hertz.

A method and device for creating a distribution of unsteady suction, the device may include ejectors; and a fluidic oscillator; wherein the fluidic oscillator may be configured to switch a first flow of fluid, in a cyclic manner, between the ejectors; wherein the ejectors may be fluidly coupled to the fluidic oscillator; and wherein each one of the ejectors may be configured to create pulsed suction through at least one first aperture, and (b) pulsed ejection through at least one second aperture.

A fluidic actuator is configured to be mounted to an airfoil surface. The actuator includes a rotor supported within a housing. The rotor contains at least one generally radially extending nozzle that converges from an entry at an interior circumference of the rotor to an exit at an exterior circumference thereof, the converging shape of the nozzle assuring high velocity airflow at the nozzle exit. In one form, each nozzle also includes a curved path by which high-pressure air is enabled to induce spinning of the rotor. The fluidic actuator further includes a diffuser through which high-pressure air from the nozzles is cyclically ejected from those of the nozzles instantaneously exposed to the diffuser. In one form, the rotor spins at 300 revolutions per second and provides nozzle ejections effective to avoid boundary layer separation; i.e. to maintain an attached boundary layer flow over the airfoil.

An intentional fluid manipulation apparatus (IFMA) assembly that includes an upstream intentional momentum shedding apparatus (IMSA) configured to impart a first induced velocity to a local free stream flow during a nominal operation requirement. The upstream IMSA creates a streamtube. The IFMA includes a downstream IMSA, with some or all of the downstream IMSA being located in a downstream portion of the streamtube. The downstream IMSA imparts a second induced velocity to the local free stream flow within the streamtube. The second induced velocity at the location of the downstream IMSA has a component in a direction opposite to the direction of the first induced velocity at the location of the downstream IMSA.

Systems and methods are described herein to implement transverse momentum injection at low frequencies to directly modify large-scale eddies in a turbulent boundary layer on a surface of an object. A set of transverse momentum injection actuators may be positioned on the surface of the object to affect large-scale eddies in the turbulent boundary layer. The system may include a controller to selectively actuate the transverse momentum injection actuators with an actuation pattern to affect the large-scale eddies to modify the drag of the fluid flow on the surface. In various embodiments, the transverse momentum injection actuators may be operated at frequencies less than 10,000 Hertz.

The systems and methods provided herein are directed to a stationary device for simulating the periodic unsteadiness typically produced by turbines in an air stream. A streamlined body includes a line of jets along its leading edge that pulses air at an angle against the air stream, and a separate line of jets along its trailing edge to expel a sustained air flow in the same direction as the air stream.