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.

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.

A vortex control device for modifying a vortex in a fluid stemming from a wall is disclosed. The device includes a rotatable hub disposed within an opening in the wall. The device also includes an inlet port and an outlet port in the rotatable hub. The inlet port forms a suction port to suction fluid from or about the vortex, and the outlet port forms an injection port to inject fluid into or about the vortex.

Techniques are disclosed for using synthetic jet technology as an air delivery device for sensing applications. In particular, a synthetic jet device is used to deliver a controlled airflow or other fluidic flow to a sensor measurement area. Such a sensing system can be used to detect accurate concentration of target features present in the ambient surroundings, such as gases, particles, solutions, mixtures, and any other environmental features that can be sensed from a controlled airflow. An example application is air quality monitoring by using one or more synthetic jet devices to deliver a known or otherwise controlled airflow to a sensing area, thereby allowing for detection of harmful or otherwise unacceptable concentrations of particulate matter, gases, or air pollutants. In some embodiments, a synthetic jet device is operatively coupled with a sensor via a flow channel in a common housing, so as to provide a controlled flow sensing system.

A fluidic control system (1) for controlling a vehicle, which includes a controller (2) and a closed fluidic circuit. The circuit includes a pump (3) for pressurizing fluid in the circuit, valve means (40, 50, 60), an actuator (4, 5, 6) and a precharge accumulator (7). The valve means (40, 50, 60) is fluidly connected to the inlet and outlet of the pump (3) and the actuator (4, 6) is fluidly connected to the valve means (40, 50, 60) for selectively receiving pressurized fluid therefrom. The precharge accumulator (7) includes a movable member (73, FIG. 2) that describes a variable volume (71) fluidly connected to the circuit between the valve means (40, 50, 60) and the inlet of the pump (3). The system (1) also includes a sensor (70) for determining the position of the movable member (73) for estimating the quantity of fluid and/or detecting an abnormal pressure variation within the circuit.

An intentional fluid manipulation apparatus (IFMA) assembly with a first thrust apparatus that imparts a first induced velocity to a local free stream flow during a nominal operation requirement. The first thrust apparatus creates a streamtube. A second thrust apparatus is located in a downstream portion of the streamtube. The second thrust apparatus imparts a second induced velocity to the local free stream flow. The second induced velocity at the location of the second thrust apparatus has a component in a direction opposite to the direction of the first induced velocity at the location of the second thrust apparatus.

Examples of system for generating vortex cavity are disclosed. The system comprises a vessel into which a fluid is injected through one or more inlet ports and a fluid circulating system configured to circulate the fluid through the vessel such that the fluid is removed from the vessel through an outlet port and is returned back into the vessel through the one and more inlet ports. A first spinner is mounted at one wall of the vessel while a second spinner is mounted at the opposite wall of the vessel such that the second spinner is at some distance away from the first spinner and it faces the first spinner. When the fluid circulating system starts circulating the fluid within the vessel a vortex cavity is formed that extends between the first and the second spinners so that one end of the vortex cavity sits on the first spinner while the opposite end of the vortex cavity sits on the second spinner.

A clampless synthetic jet actuator includes a cavity layer having an internal cavity for reception of a fluid volume and an orifice providing a fluid communication between the cavity and an external atmosphere; and an oscillatory membrane having a piezoelectric material adapted to deflect the oscillatory membrane in response to an electrical signal. The cavity has an opening in at least one planar surface of the cavity layer, and the cavity layer and the oscillatory membrane are joined by a high strength, low shear modulus adhesive material with the oscillatory membrane positioned adjacent to the planar surface having the cavity opening and adapted as an enclosing surface to said cavity opening. The oscillatory membrane is adapted to compress and expand a volume within the cavity, based on a deflection generated by the piezoelectric material, for generating a fluid flow between the cavity and the external atmosphere through the orifice.

An apparatus for suppressing shock-induced separation of high speed airflow from a relatively low-energy boundary layer. The apparatus may include an actuator or array of actuators configured to alternately inhale and exhale fluid and positioned to alternately inhale fluid from and exhale fluid into a boundary layer of a fluid mass flowing along the wall. The actuator may be positioned to inhale fluid from a boundary layer separation bubble induced by a supersonic shock wave propagated in the fluid mass.

A device including a resonant array of a plurality of synthetic jet generators where neighboring jet generators are coupled, resulting in the potential for constructive and destructive interference between jets of the plurality of synthetic jet generators depending on the relative phase of a corresponding plurality of drive signals to plurality of synthetic jet generators. The device also includes a controller configured to control the relative phase of the corresponding plurality of drive signals to effect a change in a first jet emitted by a first synthetic jet generator of the plurality of synthetic jets by changing a given phase of a second jet emitted by a second synthetic jet generator of the plurality of synthetic jet generators.