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, fluid mixing, heat transfer, and/or other interactions of the fluid flow with the surface. In various embodiments, the transverse momentum injection actuators may be operated at frequencies less than 10,000 Hertz.

A flow control apparatus includes a plasma actuator, a storage device, and a control circuit. The plasma actuator causes discharge in a discharge area by applying an alternating-current (AC) voltage between electrodes to form an induced flow of gas. The electrodes are shifted relatively to each other with a dielectric disposed between them. The storage device stores a changing condition of an AC voltage waveform for changing a gas flow state formed in a flow control area of gas from a first state to a second state by adding the induced flow of gas. The control circuit refers to the changing condition of the AC voltage waveform and control the AC voltage waveform based on the changing condition of the AC voltage waveform, in a case of changing the gas flow state formed in the gas flow control area from the first flow state to the second flow state.

A fluid control system includes a dielectric-barrier discharge (DBD) device, and processing circuitry. The processing circuitry is configured to obtain a streamwise length scale of a fluid flowing over a surface. The processing circuitry is also configured to obtain a convective time scale of the fluid flowing over the surface. The processing circuitry is also configured to operate the DBD device, based on the streamwise length scale and the convective time scale, to adjust a flow property of the fluid.

An aircraft control system includes a flow control device and a control circuit. The flow control device is configured to control a flow of air around an aircraft. The control circuit is configured to control the flow control device so that a pressure distribution loaded on a surface of a structure that constitutes the aircraft is equal to a control value of a pressure distribution calculated based on a physical quantity detected by a sensor provided in the aircraft. The physical quantity relates to the air.

A flow control system includes a movable wing attachable to a wing of an aircraft, and a plasma actuator mountable on a surface of the movable wing. The flow control system is configured to control air flow around the wing by having the changing of the steering angle of the movable wing work in conjunction with the operation of the plasma actuator.

A flight propulsion system for Vertical Take-Off and Landing (VTOL) and Short Take-Off and Landing (STOL) aircraft, having a two cyclorotors, installed in the front and rear portions of a pair-wings mechanism involving top wing and bottom wing, three degree-of-freedom DOF adjusting mechanism for pair-wings, a dielectric barrier discharge (DBD) plasma actuators, a bar mechanism for pitching oscillation and rotation speed controls and rear cyclorotor, a yawing mechanism for rear cyclorotor, all on each side of the flight vehicle. This propulsion system is particularly useful for VTOL aircraft. The main features are: high controllability and manoeuvrability, low noise and environmental pollutions, VTOL, STOL, hover state flights, marine and ground take-off and landing, high safety, suitable for different aircraft scales and for different missions and purposes, instant altering the flight direction.

A rotor support device includes a plurality of first electrodes, a plurality of second electrodes, a dielectric material, and at least one alternating-current power supply. The dielectric material is disposed between the plurality of first electrodes and the plurality of second electrodes. The at least one AC power supply is configured to apply an alternating-current voltage across the plurality of first electrodes and the plurality of second electrodes and induce flows of gas by causing dielectric barrier discharge between the plurality of first electrodes and the plurality of second electrodes. At least one of the plurality of first electrodes or the plurality of second electrodes is disposed apart from each other in a static system that is stationary with respect to a rotor provided in an aircraft. The static system is adjacent to the rotor.

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.

An aircraft steering system includes an electric actuator, a clutch, at least one plasma actuator, and a controller. The electric actuator is configured to vary an angle of a flight control surface of an aircraft. The clutch is configured to cut off torque by driving of the electric actuator. The torque is to be transmitted to the flight control surface. The at least one plasma actuator is configured to form a flow of air on a surface of the flight control surface when the torque is cut off. The controller is configured to control the electric actuator, the clutch, and the at least one plasma actuator.

A plasma actuator includes: a dielectric layer; a first electrode provided on the obverse surface of the dielectric layer; a second electrode provided, on the reverse-surface side of the dielectric layer, in one direction from the first electrode; a floating conductor pair that is provided between the first electrode and the second electrode and that has an obverse-surface conductor provided on the obverse surface of the dielectric layer and a reverse-surface conductor provided on the reverse-surface side of the dielectric layer, the obverse-surface conductor and the reverse-surface conductor being electrically connected to each other, electrically insulated from the first electrode and the second electrode, and positioned in the order of the reverse-surface conductor and the obverse-surface conductor in the one direction from the first electrode in plan view; and a power source connected to the first electrode and the second electrode.