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 clawless 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 air dam for a vehicle having a front panel with a downward facing surface at a lateral front edge. At least one air curtain such as an air jet forces air downward toward the ground for creating an aerodynamic barrier of air which reduces turbulence caused by the underbody of a vehicle while the vehicle is underway.

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.

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.

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.

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.

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.

An actuator assembly is capable of manipulating a fluid flowing around a flow body, the fluid being received or able to be received in a volume of at least one cavity arranged in the flow body, and the fluid passing through at least one opening in the at least one cavity during manipulation of the fluid. In this process, the volume of the at least one cavity can be changed by moving a wall portion delimiting or defining the cavity. The actuator assembly has a drive unit with at least one actuator, which executes a periodic movement over time when actuated, causing a translational movement of the wall portion delimiting or defining the cavity and the wall portion being shaped in terms the topology thereof in such a way that it is adapted to the shape of the at least one cavity with the at least one opening thereof.

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.