Methods and systems for controlling a fluid flow field near a surface are disclosed. In some embodiments, the system includes an array of oscillating bodies disposed on the surface to provide physical modification to the flow field. Fluid jets are also emitted from an outlet in the oscillating body to provide virtual modification of the flow field through momentum addition. Fluid jet sources, including synthetic jet generators such as piezoelectric drivers and sources of compressed fluids such as air or water, are positioned to be in fluid communication with the outlet at intervals during the oscillation of the oscillating body. Controlling the oscillation amplitude and frequency of the body, as well as the location of oscillating body outlets and frequency of fluid jet emission, have advantageous effects for the surface such as improved heat transfer properties and reduction in structural vibration and noise.

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.

A removable passive airflow oscillation device can be disposed within a pressurized wing structure utilized as a plenum. The passive airflow oscillation device can be a removable insert disposed into exterior vehicle surfaces with pressurization of a sealed chamber to provide the airflow. The device can include a cavity configured to receive the airflow from an ingress opening, direct the airflow therethrough to generate a predetermined oscillating airflow, and expel the oscillatory airflow from the egress opening. The removable passive airflow oscillation devices can provide quick and simple replacement and maintenance of damaged or clogged devices. The aft chamber of the flap seal can be sealed and pressurized to serve as a plenum providing the airflow to the actuators. The device can receive airflow, such as compressor air, and expel an oscillating airflow. Because each device is self-contained the number of devices and location thereof can vary by application.

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 bimorph disk actuator is disclosed including a substrate formed from a substrate composite material and having a first substrate surface and a second substrate surface, a first piezoceramic disk rigidly connected to the first substrate surface of the substrate, a second piezoceramic disk rigidly connected to the second substrate surface of the substrate, and a first composite ring formed from a first ring composite material, rigidly connected to the first substrate surface and surrounding the first piezoceramic disk. A second composite may be rigidly connected to the second substrate surface and surrounding the second piezoceramic disk. A method and apparatus for forming the bimorph disk actuator are also disclosed.

A fluidic device for providing analogue output control includes a main channel, a first control channel, a second control channel, a comparator which receives respective input fluid flows from the main, the first and the second control channels. The first control channel is configured such that the input fluid flow therefrom carries an oscillating pressure wave signal, the second control channel includes a flow regulator controllable to vary the mass flow rate of the input fluid flow from the second control channel, and the main channel is configured such that the input fluid flow therefrom is at a reference mass flow rate. The comparator is configured such that the input fluid flows from the first control and the second control channels act in combination on the input fluid flow from the main channel to produce an output fluid flow from the comparator having a PWM mass flow rate characteristic.

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.

Methods and systems for controlling a fluid flow field near a surface are disclosed. In some embodiments, the system includes an array of oscillating bodies disposed on the surface to provide physical modification to the flow field. Fluid jets are also emitted from an outlet in the oscillating body to provide virtual modification of the flow field through momentum addition. Fluid jet sources, including synthetic jet generators such as piezoelectric drivers and sources of compressed fluids such as air or water, are positioned to be in fluid communication with the outlet at intervals during the oscillation of the oscillating body. Controlling the oscillation amplitude and frequency of the body, as well as the location of oscillating body outlets and frequency of fluid jet emission, have advantageous effects for the surface such as improved heat transfer properties and reduction in structural vibration and noise.

A tile assembly (22) which, in use, is fitted to a base structure to form at least part of a fluid washed surface. The tile assembly comprises a housing (42) with at least one plenum (45) being provided within the housing (42). A wall (44) of the housing (42) is provided with a plurality of flow passages (46) which extend from the plenum side of the wall (44) to an outer surface (48) of the wall. Flow passage closures (50) are provided which are operable to open and close at least some of the flow passages (46).