A method is provided for producing a vortex ring in a liquid medium. The method includes concatenating pairs of insulated anode and cathode rings into a stack; inserting the stack into a vertically oriented chamber; disposing a cylindrical cavity below the chamber; inserting a piston into the cavity; connecting the chamber to the medium; and raising the piston to displace the medium while the stack produces an annular bubble that induces the vortex ring. In particular, the medium is water and the stack separates the medium into hydrogen and oxygen gas.

A flat reverse vortex ring is sized and shaped to either attach to or be formed as part of a distal end of a sleeve bearing or seal. The ring has a series of evenly spaced radial channels that extend from an inner diameter to an outer diameter of the ring. The channels have a depth. The ring has an upper surface with an alternating series of planar surfaces and openings located at an upper end of the channels. The ring may have an interior diameter equal to an interior diameter of the sleeve bearing or seal. The ring may have an exterior diameter equal to an exterior diameter the sleeve bearing or seal. The channels may be semi-cylindrical. The channels have a diameter and the depth is a predetermined portion of the diameter. The channels may be rectangular in cross-section with a height-to-width ratio of between 0.5 and 1.5.

A method of controlling a fluid flow using momentum and/or vorticity injections. Actively controlling an actuator allows for direct, precise, and independent control of the momentum and swirl entering into the fluid system. The perturbations are added to the flow field in a systematic mater providing tunable control input, thereby modifying behavior thereof in a predictable manner to improve the flow characteristics.

Disclosed is a heat-transfer device adapted to enhance uniformity of cooling characteristics to be given to a heat transfer object, and thereby to extend a life of the heat transfer object. The heat-transfer device for facilitating heat exchange between combustion air (heat transfer medium) flowing along an outer surface of a combustor liner (heat transfer object), and the combustor liner, the heat-transfer device including at least one longitudinal vortex generating device protruding toward a annular passage (flow passage) of the combustion air and formed to generate a longitudinal vortex E with a central axis in a flow direction of the combustion air, and stir the combustion air flowing in the annular passage; and at least one radiator fin provided in a region A on the outer surface of the combustor liner, the region A being where a flow of the vortex E, on a swirling plane thereof, that are generated by the vortex generating device is directed from a side of the combustor liner, toward a side of a flow sleeve, the fin exchanging heat with the combustion air stirred by the vortex generating device.

A system and a method for reducing drag on the aft-fuselage of an aircraft are provided, which system and method utilize at least one (inlet provided on each side of the aft-fuselage of an aircraft for reducing drag -on the aft-fuselage, which finlets are (i) positioned at the rear half of an upswept portion of the aft-fuselage starting at a breakline, (ii) positioned in the path of the vortices generated by the aft-fuselage, and (iii) oriented at 1 to 9 degrees angle relative to the local airflow about the aft-fuselage of the aircraft to straighten the airflow about the aft-fuselage. In addition, the finlets generate an induced secondary vortex having an opposite rotation direction relative to the rotation direction of the vortices generated by the aft-fuselage, thereby counteracting the vortices generated by the aft-fuselage.

A method of controlling a fluid flow using momentum and/or vorticity injections. Actively controlling an actuator allows for direct, precise, and independent control of the momentum and swirl entering into the fluid system. The perturbations are added to the flow field in a systematic mater providing tunable control input, thereby modifying behavior thereof in a predictable manner to improve the flow characteristics.

An object is to provide a decompression device including a plurality of stages of orifice plates disposed in a flow passage, which generates less noise in response to sonic feedback phenomenon and gas-column resonance. A decompression device 10A includes: an upstream orifice plate 14 disposed in a duct 12 forming a flow passage for a fluid F; and a downstream orifice plate 16 disposed in the flow passage and downstream of the upstream orifice plate 14. A jet-flow interference part 22A is disposed only partially on an outlet rim portion of an orifice 18 on the upstream orifice plate 14 and configured to interfere with a jet flow discharged from the orifice 18. Positions of Karman vortices e are differentiated in a duct axial direction between regions with and without the jet-flow interference part 22A to reduce generation of noise.

A fluid sending apparatus includes a signal generator that generates a signal including a signal component that has a one-sided waveform and is composed of a rising component in a positive voltage direction, a falling component in the positive voltage direction, and a vortex ring formation time component T, and a damping component for driving for a predetermined time with a voltage less than or equal to one-half of a voltage in the positive voltage direction, the waveform of each of the signal component and the damping component corresponding to a single wave.

A jet flow generation device includes: a discharge electrode; a reference electrode that is disposed away from the discharge electrode; a power supply circuit that generates an output voltage to control a potential difference between the discharge electrode and the reference electrode; a controller that switches the output voltage of the power supply circuit between a first voltage that does not induce corona discharge between the discharge electrode and the reference electrode and a second voltage that induces corona discharge between the discharge electrode and the reference electrode; and a case housing at least the reference electrode has an injection port that injects an ion wind of ions generated by the corona discharge.

An arrangement for influencing a liquid flow includes a first section selectively configurable to provide a vortex generator surface, the vortex generator surface comprising a series of laterally aligned projections, to induce vortices in the liquid flow.