Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed are systems, methods, and apparatus for actively adjusting the position and/or configuration of one or more propeller blades of a propulsion mechanism to generate different sounds and/or lifting forces from the propulsion mechanism.

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed are systems, methods, and apparatus for actively adjusting the position and/or configuration of one or more propeller blades of a propulsion mechanism to generate different sounds and/or lifting forces from the propulsion mechanism.

A flow control method is a flow control method of controlling flow around a blade of a rotary wing, a plasma actuator being disposed at the blade. The flow control method includes: determining a characteristic frequency ratio that is a characteristic value among frequency ratios, each of the frequency ratios being a ratio between an actuator driving frequency and an angle of attack changing frequency, the actuator driving frequency being a frequency of an applied voltage applied to the plasma actuator, the angle of attack changing frequency being a frequency at which an angle of attack of the blade changes in accordance with a rotation angle of the blade; setting the actuator driving frequency such that the frequency ratio becomes the characteristic frequency ratio; and applying a voltage of the set actuator driving frequency to the plasma actuator to control the flow around the blade.

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed are systems, methods, and apparatus for actively adjusting the position and/or configuration of one or more propeller blades of a propulsion mechanism to generate different sounds and/or lifting forces from the propulsion mechanism.

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed are systems, methods, and apparatus for actively adjusting the position and/or configuration of one or more propeller blades of a propulsion mechanism to generate different sounds and/or lifting forces from the propulsion mechanism.

The invention discloses an aircraft generating a larger thrust and lift by fluid continuity. First open channels used to extend fluid paths are formed in front parts and/or middle parts of windward sides of wings of the aircraft and extend from sides, close to the fuselage, of the wings to sides, away from the fuselage, of the wings, and the first open channels are concave channels or convex channels, so that a pressure difference in a direction identical with a moving direction is generated from back to front due to different flow speeds of fluid flowing over the windward sides of the wings in a lengthwise direction and a widthwise direction to reduce fluid resistance, and a larger pressure difference and lift are generated due to different flow speeds on the windward sides and leeward sides of the wings.

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 flow control method is a flow control method of controlling flow around a blade of a rotary wing, a plasma actuator being disposed at the blade. The flow control method includes: determining a characteristic frequency ratio that is a characteristic value among frequency ratios, each of the frequency ratios being a ratio between an actuator driving frequency and an angle of attack changing frequency, the actuator driving frequency being a frequency of an applied voltage applied to the plasma actuator, the angle of attack changing frequency being a frequency at which an angle of attack of the blade changes in accordance with a rotation angle of the blade; setting the actuator driving frequency such that the frequency ratio becomes the characteristic frequency ratio; and applying a voltage of the set actuator driving frequency to the plasma actuator to control the flow around the blade.

A method to control flow separation over an airfoil, turbine blade or compressor blade includes providing an airfoil having a body with an upper surface and a lower surface that extend from a leading edge to a trailing edge; providing a flow separation control device having a plurality of openings on the upper surface of the body and a plurality of capillary tubes in gaseous communication with the plurality of openings; and injecting gas through the plurality of capillary tubes into a portion of the airstream passing over the uppers surface of the body.

A ducted fan assembly for generating thrust during edgewise forward flight. The ducted fan assembly includes a duct having an inlet with a leading portion and a diffuser with a trailing portion during the edgewise forward flight. A fan disposed within the duct is configured to rotate relative to the duct about a fan axis to generate an airflow through the duct from the inlet to the diffuser. An active flow control system includes a plurality of injectors including a first injector configured to inject pressurized air substantially tangential with the leading portion of the inlet and a second injector configured to inject pressurized air substantially tangential with the trailing portion of the diffuser such that when the injectors are injecting pressurized air, flow separation of the airflow at the leading portion of the inlet and the trailing portion of the diffuser is reduced.