A lift control device actively controls the lift force on a lifting surface. The device has a protuberance near a trailing edge of its lifting surface, which causes flow to separate from the lifting surface, generating regions of low pressure and high pressure which combine to increase the lift force on the lifting surface. The device further includes a means to keep the flow attached around the protuberance or to modify the position of the protuberance in response to a command from a central controller, so as to provide an active control of the lift between a maximum value and a minimum value.

The systems and methods provided herein are directed to a stationary device for simulating the periodic unsteadiness typically produced by turbines in an air stream. A streamlined body includes a line of jets along its leading edge that pulses air at an angle against the air stream, and a separate line of jets along its trailing edge to expel a sustained air flow in the same direction as the air stream.

Methods described herein provide a way to reduce or eliminate drag and adhesion of a substance flowing over a surface by creating a vapor cushion via evaporation of a phase-changing material of or on the surface or encapsulated within textures of the surface. The vapor cushion causes the flowing substance to be suspended over the surface, greatly reducing friction, drag, and adhesion between the flowing substance and the surface. The temperature of the flowing substance is above the sublimation point and/or melting point of the phase-changing material. The phase-changing material undergoes a phase change (evaporation or sublimation) upon contact with the flowing substance due to local heat transfer from the flowing substance to the material, generating a vapor cushion between the solid or liquid material and the flowing substance.

A bullhead-shaped grooved diversion jet and empennage swing vibration suppression device and method. The device consists of an impeller diversion module and a drainage rotary cover module. The impeller diversion module consists of a center impeller, sleeve bearings, small impellers, and small impeller rotating shafts. The drainage rotary cover module consists of a drainage front cover, a perforated jet rear cover, and empennages. The device is mounted on an outer wall of a riser in a sleeving manner. Under a combined action of drainage and space allocation of horizontal rectangular grooves, flow rate distribution of the center impeller, flow direction adjustment of the small impellers, diversion of lateral diversion holes, jet flows of side rear reducing holes, flowing space division and wake vortex turbulence of rotary swinging empennages, around-flow boundary layers at two sides and a tail of the riser are deeply damaged, which suppresses the formation of large vortexes.

Enhanced high-speed aircraft performance, including increased lift/drag ratio, from localized high-temperature speed of sound increases, and associated systems and methods are disclosed. A representative method for operating a vehicle includes, while a lifting body of the vehicle is immersed in a gas, heating the gas in a target volume sufficiently to increase the speed of sound in the gas relative to the speed of sound in the gas outside the target volume. The target volume can be positioned adjacent to, forward of, and/or along a pressure surface of the lifting body.

A lift control device actively controls the lift force on a lifting surface. The device has a protuberance near a trailing edge of its lifting surface, which causes flow to separate from the lifting surface, generating regions of low pressure and high pressure which combine to increase the lift force on the lifting surface. The device further includes an arrangement to keep the flow attached around the protuberance or to modify the position of the protuberance in response to a command from a central controller, so as to provide an active control of the lift between a maximum value and a minimum value.

A pressure wave generator with dynamic reflector of pressure impulse is disclosed which comprises an outer fixed and an inner coaxially-rotating cylindrical elements with the given profiled openings of the given shapes and sizes in the solid walls and a dynamic reflector of pressure impulse, configured in the solid wall of the inner rotating cylindrical element having a longitudinal radial-azimuthal variable-concave surface. Such concave surface provides a decomposition of the reflected pressure impulse to a radial and azimuthal component, especially important on the stage of decrease of the pressure amplitude from a maximal value to zero. Variation of the curvature of the radial-azimuthal shape of the concave surface provides a maximal azimuthal component and a minimal radial component of the mechanical reaction of the shaft of the pressure wave generator. The helicoidally-shape of the inner surface of a collector add an azimuthal motion to reflected pressure impulse.

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 microstructured surface with microfeatures formed thereon and defining spaces between the microfeatures includes least one electrode of an electrode pair in the spaces, wherein electrodes of the pair are electrically connected to one another. The at least one electrode located in the space is configured to generate a gas in between the microfeatures when an electrolyte solution penetrates into the microfeatures. Importantly, the electrodes are not connected to any external power source. Because the microstructured surface is self-powered in replenishing the gas lost in a submerged condition, no additional provision to supply energy or regulate the replenishment is necessary for implementation and use.

A method and apparatus for generating a wave in a body of water may include altering a flow of water as it is urged through an inlet, contoured passage, and outlet. For example, a primary flow of water may be altered so that one or more secondary flows are created at angles to the direction of primary flow.