Disclosed are fluidic actuator systems for active flow control applications, methods for making/using such fluidic actuator systems, and vehicles equipped with fluidic actuators to modify airfoil aerodynamics. A Spanwise Traveling Electro-Pneumatic (STEP) actuator architecture for active flow control (AFC) generates variable actuation using high-speed electronic valves to move an array of discrete jets in a spanwise direction. The STEP actuator uses pneumatic power to provide flow control authority and electric power to minimize system power requirements. Disclosed STEP actuator systems help to reduce mass flow requirements for equivalent flow control performance, e.g., when compared to steady blowing systems. This flow control approach may provide necessary flow control authority, for example, for high-lift systems, while keeping pneumatic power requirements (e.g., mass flow and pressure) for the AFC system within an aircraft's capability for system integration. Disclosed STEP actuators systems may regulate spanwise flow encountered by many aircrafts, including swept-back wing configurations.

A method and apparatus are presented. An active flow control system comprises a flow control valve, a manifold, and a temperature control system. The flow control valve is configured to control a flow of air into the manifold. The manifold is operatively connected to a number of actuators. The temperature control system is configured to heat at least a portion of the flow of air.

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.

Fluid systems are described herein. An example embodiment of a fluid system has a lengthwise axis, a chord length, a first body portion, a second body portion, a spacer, and a fluid pressurizer. The first body portion and the second body portion cooperatively define an injection opening, a suction opening, and a channel that extends from the injection opening to the suction opening. The fluid pressurizer is disposed within the channel cooperatively defined by the first body portion and the second body portion. The first body portion defines a cavity that is sized and configured to filter debris that enters the channel during use and provide a mechanism for removing the debris from the system.

A body adapted for relative movement with respect to a fluid, said movement creating a flow of fluid with respect to the body in a relative flow direction, said body having at least one surface with a surface profile exposed to the fluid and comprising at least one smooth step facing in relative flow direction towards the flow, said step having a height between 4% and 30% of the local boundary layer thickness (.sub.99) of the fluid contacting the body in the vicinity of the step.

An apparatus for determining a movement direction of a component of a mechanism. The apparatus includes an acoustic emission sensor arranged to detect acoustic emission from the mechanism, and a processor arranged to determine a Doppler shift in a frequency characteristic of the measured acoustic emission and to determine a movement direction of a component of the mechanism on the basis of the determined Doppler shift. A method of determining a movement direction of a component of a mechanism including detecting acoustic emission from the mechanism and determining a Doppler shift in a frequency characteristic of the measured acoustic emission and, determining, based on the Doppler shift in the frequency characteristic, a movement direction of the component of the mechanism.

A method of controlling an aircraft bleed may include the steps of monitoring a temperature of a precooled airflow exiting a precooler, and determining a status of a wing anti-ice system of an aircraft. The wing anti-ice system may be configured to receive the precooled airflow from the precooler. The method may further comprise the steps of determining whether an engine operating condition of the aircraft is within an icing envelope, selecting a temperature set point for the precooled airflow based on the status of the wing anti-ice system and whether the aircraft is within an icing envelope, and modulating a fan airflow from a fan to the precooler to adjust the temperature of the precooled airflow to the temperature set point.

An aircraft is provided including a fuselage extending between a forward end and an aft end. An aft engine is mounted to the fuselage at the aft end of the fuselage. The aft engine includes a nacelle having a forward section. An airflow duct is also provided extending at least partially through the nacelle and including an opening on the forward section of the nacelle. The opening is configured for providing an airflow to, or receiving an airflow from, the forward section of the nacelle to increase an amount of, e.g., boundary layer airflow received within the aft engine during operation of the aircraft, to guide the flow of boundary layer airflow into the engine more smoothly, or to reduce a distortion on the engine.

A drag reduction system for an aircraft may include an air ejector having an ejection port located between an aft portion of an airfoil main element and a forward portion of a trailing edge device. The air ejector may be configured to discharge an air jet from the ejection port in such a manner that the air jet passes over the upper surface of the trailing edge device.

The invention relates to a fluid actuator for influencing the flow along a flow surface by 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 supplied with fluid flow via a feed line. Into this interaction chamber there merge at least two control lines via control openings to which respective different pressures may be applied. The flow in the interaction chamber is distributed to the individual outlet openings as a function of the pressure difference at the control openings.