A fluidic oscillator includes a structure having an input port and an output port. A chamber within the structure is configured to channel a fluid from the input port to the output port. A volume of the chamber is configured to change so as to change to change a frequency at which the fluid flows out of the output port.

A piezoelectric bimorph actuator with an integral compliant boundary employs a first piezoelectric element, a second piezoelectric element and a composite layer intimately engaged between the first and second piezoelectric elements to form a bimorph actuator. The composite layer extends from a peripheral edge of the piezoelectric elements and has a curved interface portion providing a mount for attachment of the bimorph actuator.

A fluidic system is disclosed. The system comprises a plurality of fluidic oscillatory actuators, and at least one synchronization conduit connecting two or more of the actuators such as to effect synchronization between oscillations in the two or more connected actuators.

A plasma-assisted synthetic jet device, an aircraft including a plasma-assisted synthetic jet device, and a method of improving aerodynamic properties are disclosed for providing air flow control at an aerodynamic structure by ionizing one or more gases exiting through an aperture of the synthetic jet device disposed in the aerodynamic structure.

An unmanned aerial vehicle (UAV) is provided with a plurality of synthetic jet actuators and a nonlinear robust controller. The controller compensates for uncertainty in a mathematic model that describes the function of the synthetic jet actuators. Compensation is provided by the use of constant feedforward best guess estimates that eliminate the need for more highly computationally burdensome approaches such as the use of time-varying adaptive parameter estimation algorithms.

A method for generating fluid pulses is provided. The device comprises a first channel with a first fluid inlet and a second channel with a second fluid inlet, in which the first fluid inlet and second fluid inlet are substantially situated opposite each other. The first channel comprises a first control outlet at the height of the first fluid inlet, and the second channel comprises a second control outlet at the height of the second fluid inlet, in which the respective control outlet is located in front of the respective fluid inlet in relation to the inflowing direction of the fluid inlet.

A cooperative actuator system for active flow control, a vehicle comprising such cooperative actuator system, and a method for operating an actuator system for active flow control. The cooperative actuator system includes actuators, a control unit, and a data unit. The actuators are distributed along the surface in at least a first group and a second group downstream of the first group. The control unit is configured to control the actuators of the first group so that they form a first flow structure along the surface. The data unit is configured to provide data of the first flow structure. The control unit is further configured to control the actuators of the second group based on the data of the first flow structure, so that the actuators of the second group cooperatively interact with the first flow structure to form a second flow structure along the surface.

An active flow control drag-induced damping reduction apparatus. The apparatus includes a variable frequency signal power supply; a jet generator defining an internal cavity and having pump member, and coupled to the variable frequency signal power supply to receive a control signal; a feedback sensor coupled to the pump member to generate a feedback signal measuring the reciprocating motion of the pump member; a detection circuit that receives the feedback signal and measures a difference compared to the variable frequency generator; and an adjustment circuit that receives the measured difference and tunes the variable frequency signal of the variable frequency signal power supply to maintain the jet generator at an optimum flow.

The invention relates to fluid actuator for influencing the flow along a flow surface through ejection of a fluid. By means of a like fluid actuator, a continuous flow is distributed to at least two outlet openings in order to generate fluid pulses out of these outlet openings. Control of this distribution takes place inside an interaction chamber which is supplied with fluid flow via a feed line. Into this interaction chamber there merge at least two control lines via control openings to which a respective different pressure may be applied. Depending on the pressure difference at the control openings, the flow in the interaction chamber is distributed to the individual outlet openings.

Method and apparatus for controlling the aerodynamics of an aircraft using an active flow control system is disclosed herein. In one example, the active flow control system includes an airframe and a plurality of fluidic oscillators. The airframe includes an inlet configured for flight speeds ranging from subsonic to hypersonic. The plurality of fluidic oscillators is mounted about a curvature of the airframe. Each fluidic oscillator includes a body and an integral nozzle coupled to the body. The body has an inflow portion and a narrow nozzle inlet formed opposite the inflow portion. The integral nozzle is coupled to the body by the narrow nozzle inlet. The narrow nozzle inlet forms a single fluid flow path from the inflow portion to the narrow nozzle inlet.