Abstract: Skin friction reduction on a surface moving relative to a fluid can be obtained by ejecting a polymer-water mixture/solution into the boundary layer. The efficacy of the ejected polymer-water mixture/solution is closely related to polymer dissipation out of the boundary layer and conditioning (i.e, lenthening, unwinding or stretching) of the polymer molecules by liquid shear forces immediately before ejection. The invention is a method and apparatus for conditioning and ejecting a polymer-water mixture/solution that improves drag reduction characteristics of the mixture/solution and maintains the mixture/solution in the boundary layer for as long as possible. By improving the drag-reduction characteristic in the polymer-water mixture/solution and by extending the time it remains in the near-wall region, the ejector can increase the performance and reduce the volume and storage requirements of a drag-reduction system.

Abstract: The invention relates to a fluidic oscillator which is symmetrical with respective to a longitudinal symmetry plane, comprising a fluid inlet intended to form a bidimensional fluid jet which oscillates transversally with respective to the symmetry plane, an obstacle wherein is arranged a cavity which faces said fluid inlet and which is scavenged by the oscillation jet, characterized in that the obstacle has a front wall which has two so-called front surfaces substantially planar and framing the cavity, the plane of each surface being substantially perpendicular to the symmetry plane, said cavity being defined by a surface which is substantially parallel to said plane at the points where said surface joins each of said front surfaces, the obstacle also having two side walls of which said side surfaces are substantially parallel to the symmetry plane at the points where each of them joins the corresponding front surface.

Abstract: A low pressure fluidic oscillator having an oscillation chamber having a centerline, and a pair of mutually facing and complementary-shaped sidewalls, planar top and bottom walls, upstream end and downstream end walls. An input power nozzle is formed in the upstream end wall having a width P.sub.W and a depth PD.sub.D, for issuing a jet of liquid into the oscillation chamber and forming alternately pulsating vortices in the oscillation chamber on each side of the jet, respectively. An outlet opening is formed in the downstream end wall and substantially axially aligned with the power nozzle. A pair of short sidewalls diverge in a downstream direction from the outlet opening. The distance from the power nozzle to the outlet opening being L. A slot is formed in at least one of said top and bottom walls, the slot having a slot centerline which is spaced upstream from the outlet opening a distance from about the edge of the downstream end of said oscillation chamber to about 0.48L.

Abstract: A fluidic oscillator is disclosed for providing oscillating flow to outlet ports (172, 173). The fluid oscillator (100) in one embodiment has no fluid communication between a pair of diverging diffuser legs (163, 164) downstream of the upstream edge (169) of a splitter (165) and no fluid communication between a chamber (162) and either of the diverging diffuser legs downstream of the splitter edge. In other embodiments, a turbulent flows generator is formed by use of bump step (202), pins (220, 230), surface discontinuities (250) or a combination thereof.

Abstract: Micropumps fabricated by micromachining techniques and employing fixed or no-moving-parts valves. As one aspect of the invention, a laser-assisted chemical etching technique is employed for providing smooth-walled, curved configuration necessary to obtain the desired flow characteristics of the valves that are used in conjunction with the micropump.

Abstract: A fluidic oscillator comprises a housing having interior walls defining a cylindrical space therein, a fluidic oscillator is mounted in said cylindrical space and has an oscillating chamber having an upstream end and a downstream end. A power nozzle issues a jet of fluid into the oscillation chamber from the upstream end thereof, an outlet formed in the downstream end. A pair of control ports at opposing sides of the power nozzle are coupled to a pair of feedback entranceways in the downstream end of the oscillator chamber and at corresponding opposing sides of the outlet. The control passageways connect each feedback entranceway with the a control port on the opposing sides, respectively. Each control passageway is formed in part by the interior wall and the oscillator element.

Abstract: A device for automatically producing periodical impulse changes in a pressure line is provided with an elastic intermediate member impacted by a control pressure. Pressurizing the exterior of the intermediate member produces a pulsating flow of the fluid in the pressure line, obviating the use of control members, flaps, etc. In a preferred embodiment, the required control pressure is drawn from a bypass in the pressure line. The present invention may be put to Advantageous use in numerous fields in pneumatic and in process engineering.

Abstract: Process for damping pressure pulsations and apparatus for performing the process. The process of this invention serves for the damping of pressure pulsations in a fluid, particularly a fiber suspension, flowing in a closed system wherein the pressure pulsations to be damped are measured at a measuring site and compensated at a correction site, with a throttle position being located between the measuring and the correction sites, with the damping of the imparted pressure impulses occurring at the correction site, which pressure impulses are opposite to the measured pressure pulsations, with the time periods thereof being about the same as those of the measured pressure pulsations. Several apparatuses for performing the process are also set forth.

Abstract: The invention provides a fluidic oscillator which is symmetrical about a longitudinal plane of symmetry (P), the oscillator comprising means for generating an oscillating two-dimensional fluid jet, an obstacle provided in its front portion with a cavity that is swept by the oscillating jet, and a longitudinal element disposed in the empty space situated downstream from said obstacle in such a manner as to partially subdivide said space into two identical zones, and to form between them at least one communication channel for the fluid. The invention also provides a fluid flow meter including such a fluidic oscillator.

Abstract: A plate-type nozzle and a method of using same to atomize a liquid are disclosed, wherein the nozzle contains at least one nozzle plate having formed on a common facial surface thereof at least one atomization chamber containing: an inlet for a liquid stream; a jet-forming channel downstream of and in fluid communication with the inlet, the jet-forming channel being adapted to convert the stream into a jet; an interaction channel downstream of and in fluid communication with the jet-forming channel and having opposite first and second sides, the jet passing between the first and second sides and forming an attachment to either the first or second side; a split path having first and second branch channels associated with the respective first and second sides of the interaction channel, wherein attachment to the first side causes the jet to flow entirely into the first branch channel while attachment to the second side causes the jet to flow entirely into the second branch channel; at least one control channel

Abstract: A fluidic oscillator and a flow meter including such a fluidic oscillator comprising a fluid inlet suitable for forming a two-dimensional jet: an obstacle possessing a front portion in the form of a chamber facing the inlet on the path of the jet, said chamber including two walls that are symmetrical about a longitudinal plane of symmetry passing through said inlet, the walls meeting said plane; and means for increasing the pressure on each of the lateral flanks of the obstacle in the vicinity of the front portion in alternation and in a relationship with the oscillation of the jet between the walls of the chamber.

Abstract: A fluidic generator (38) employing a fluidic feedback oscillator (12) in combination with a magnetogenerator (41) is described. Oscillational changes in pressure produced within the feedback oscillator are transmitted to opposite sides of a pole cap (74) which reciprocates a coil (70) in a magnetic field.

Abstract: A single-stage and multiple-stage fluidic rectifier wherein each stage has a trunk channel and a reversing channel that joins the trunk channel at a downstream position of the trunk channel, downstream with respect to fluid flowing in a reverse direction through the fluidic rectifier. A first vena contracta is formed upon entry of the fluid into the body, when the fluid is flowing in the reverse direction. Further vena contractas are formed within the trunk channel of each corresponding stage, preferably by flow through the reversing channel being discharged and impinged upon flow through the trunk channel. Such discharged flow from the reversing channel contracts the flow through the trunk channel at a particular area. When fluid flows through the fluidic rectifier in a forward direction, each vena contracta is disabled. Thus in the forward direction, the overall head loss of the fluidic rectifier is less than the overall head loss of the fluidic rectifier when the fluid is flowing in the reverse direction.

Abstract: A drilling bit having an irrigation system which uses an irrigating fluid. The bit comprises a hollow drill head 14 housing at least one fluidic oscillator 23, 23' which includes an accelerator nozzle 26, 26' supplied by said fluid and opening into a cavity 46, 46' in which a dividing element 34, 34' is mounted which is provided with a ridge 36, 36' located slightly downstream from the nozzle. Said dividing element defines in said cavity two passages 42, 44, 42', 44' towards which the fluid is alternately directed in pulsed jets. Said passages are linked respectively to two series of channels 16 to 22 which open onto the outer surface of the head 14 through a plurality of outlet openings 21 which are oriented so that the pulsed jets they give out are directed to selected portions of the head that need to be cleaned, cooled or lubricated.

Abstract: A fluidic oscillator which is free of feedback passages has an oscillation chamber having a length greater than its width, a pair of mutually facing and complementary-shaped sidewalls, planar top and bottom walls, and first and second end walls. An input power nozzle is formed in said first end wall having a width W and a depth D, for issuing a stream of fluid into the oscillation chamber, and form alternately pulsating, cavitation-free vortices in said oscillation chamber on each side of the stream. An interconnect passage or channel proximate the downstream end wall enlarges the sweep angle and improves periodicity of the oscillations. The outlet wall is hingedly connected to a chamber wall and the chamber is such that it can be molded with the outlet wall hingedly connected thereto in one molding and forms one side of the interconnect passage or channel.

Abstract: A hydrofluidic oscillator including a momentum exchange fluidic amplifier coupled to a four-way reciprocal valve. The four-way valve is connected to control flow of hydraulic fluid from a source thereof to a using apparatus. The fluidic amplifier is connected to provide input signals to the four-way valve to cause the four-way valve to reciprocate responsive to the input signals. Both negative and positive feedback paths are provided from each outlet of the fluidic amplifier to the respective control ports to control oscillation of the four-way valve.

Abstract: A fluidic oscillator which is free of feedback passages has an oscillation chamber having a length greater than its width, a pair of mutually facing and complimentary-shaped sidewalls and planar top and bottom walls, and first and second end walls. Stabilization ribs are formed on at least one of the top and bottom walls. An input power nozzle is formed in said first end wall having a width W and a depth D, for issuing a stream of fluid into the oscillation chamber, and form alternately pulsating, cavitation-free vortices in said oscillation chamber on each side of the stream. An outlet opening formed in the downstream end wall and axially aligned with the power nozzle and has a width and depth such that internal pressure in the oscillation chamber is greater than ambient. The outlet wall is hingedly connected to a chamber wall and the chamber is such that it can be molded with the outlet wall hingedly connected thereto in one molding.

Abstract: In accordance with an illutrative embodiment of the present invention, a fluidic oscillator includes a transverse vacuum port which extends between the diffuser legs a predetermined distance below the leading edge surface of the splitter. When flow is down one leg, a slight negative pressure condition is created in the port and transmitted thereby to the other leg, which causes switching of the flow to such other leg. The process then repeats in response to negative pressure in the one leg to cause switching of the flow back thereto. Fluid flow thus is switched back and forth between the legs at a resonant frequency, so that continuously fluctuating pressures are applied to the surrounding medium.

Abstract: A method of and apparatus are disclosed for producing alternating pressure in a theapeutic device used to apply compressive forces to a portion of a human body to enhance venous blood flow and prevent venous thrombosis and pulmonary embolism in surgical patients. The apparatus comprises at least two sets of a plurality of inflatable bladders or chambers arranged in alternating relation to one another. All the bladders of one set are inflated and deflated alternately with the deflation and inflation of all the bladders of the other set to produce a therapeutic alternate chamber pumping action on that portion of the body being treated. A single fluidic flip-flop device controls the supply and venting of pressurized fluid to and from the chambers.

Abstract: A fluid dispersal device utilizes alternately pulsating vortices to cyclically oscillate a fluid stream transversely of its flow direction in a desired flow pattern. A pair of pulsating fluid streams, which may issue from a fluidic oscillator are projected into an output region or chamber defined in a body member the output region or chamber having inlets for the pulsating fluid streams and at least one outlet opening with the outlet opening being positioned to issue pressurized fluid from the chamber into an ambient atmospher. Vortices formed in the chamber are alternately oppositely rotating and cause the flow pattern to cyclically sweep across the outlet. The vortices have axes normal to the direction of fluid flow and alternately spin in first and second directions in response to inflowing of the first and second pulsating fluid streams to the chamber and the output flow is cyclically swept back and forth as each vortex spins in the first and second directions respectively.

Abstract: A fluidic flowmeter is provided for measuring fluid flow comprising an inlet nozzle, a chamber and splitter located on a centerline with a feedback channel on each side of the chamber with the channel inlet disposed on each side of the apex of the splitter. An outlet channel is disposed on each side of the chamber with the apex of the feedback channel inlet disposed between the outlet channel and the feedback channel. The distance from the mouth of the nozzle to the splitter is greater than the distance between the mouth of the nozzle to the apex between the feedback channel and the outlet channel to provide improved uniformity and sensitivity in measuring fluid flow.

Abstract: Fluidic volumetric flow meter method and apparatus wherein undesirable dynamic interaction (ringing) which could appear in an output signal is inhibited. Electrical isolation and shielding also contribute to a high quality output signal in accordance with the invention. Particularly advantageous housing structures adapt the flow measurement device to a variety of applications as a complete flow meter.

Abstract: A fluidic circuit (10) having two oscillators (22,24) which separately vent to a common volume (78) and receive pressurized fluid inputs along separate flow paths (54,56) is provided with filters (80) positioned both upstream and downstream from each oscillator. Each of the filters (80) is adapted to attenuate oscillator-induced noise and comprises a series combination of an inductive element (82), a capacitive element (84), and an inductive element (86).

Abstract: A fluidic flowmeter having a reduced diameter pipe portion, a discharge nozzle and an enlarged diameter pipe portion disposed in series in the order of fluid flow direction, a pair of control nozzles formed on a boundary between the discharge nozzle and the enlarged diameter pipe portion and oriented substantially normal to the discharge direction of the discharge nozzle, the control nozzles facing each other, a pair of return flow passages connecting between the respective control nozzles and a downstream side of the enlarged diameter pipe portion, a target for stabilizing switching of fluid flow direction at the enlarged diameter pipe portion, a flow amount measuring sensor for detecting a variation in pressure or flow amount due to a variation in the flow direction of discharged fluid from the discharge nozzle, a pair of first partition walls for sectioning the enlarged diameter pipe portion, the control nozzles and the return flow passages, a second partition wall for forming discharge passages together w

Abstract: A trapped-vortex pair flowmeter having a body with an inlet and an outlet. The inlet has a nozzle which forms a fluid jet having two primary counter-rotating vortices. The body has a chamber between the inlet and outlet through which the fluid jet flows. Two wedges are secured within the chamber. Each wedge has an inner side and an outer side. The inner sides of both wedges form a converging channel between the upper portions of both wedges. Both wedges have a gap between the inner sides of the wedges through which the converging channel passes. The inlet nozzle directs the fluid jet into the converging channel. A small portion of the fluid jet flows through the gap within the converging channel, but the majority of the fluid jet flows back over the top sections and down the outer sides of the wedges. Pressure sensors located within the chamber detect alternating high and low pressures at various points within the chamber.

Abstract: A switching mechanism and valve using the same wherein a two remote valve or switch positions are provided. The switching mechanism includes a valve operator having of outwardly extending port closures that move above a central pivot point. As the valve operator shifts between its two remote positions, each port closure closes or opens respectively a port associated with such port closure. A flat bearing surface is formed as part of the valve operator and is in a plane generally perpendicular to a line bisecting the angle between the two port closures. A roller, biased against that flat bearing surface is on a pivot arm also moveable about its remote pivotable end. The biased roller normally holds the valve or switch in one of its remote positions.

Abstract: A window washer comprises a washer liquid jet nozzle provided under a windshield glass of a vehicle so as to be directed thereto for periodically deflecting the jetting direction of the washer liquid horizontally by the fluidic self-oscillating operation thereof, a pump provided in a washer liquid passage connecting the jet nozzle to a washer liquid tank for pressurizing the washer liquid and sending the pressurized washer liquid, a driving motor for driving the pump and a motor control circuit for applying a square pulse shaped voltage to the motor. The motor control circuit periodically operates the pump so that the discharge pressure thereof periodically changes. Consequently, the jetting direction of the washer liquid jetted from the jet nozzle is periodically deflected horizontally and vertically.

Abstract: An invention is disclosed in which a fluidic counter generates fluidic switching signals in response to a fluidic oscillator for sequentially activating a plurality of fluidically activated electrical switches for multiplexing a plurality of electrical conductors into a single conductor.

Abstract: There is disclosed a fluidic oscillator in which a stream of fluid is directed against a barrier member in an oscillation chamber. The barrier member serves as one wall of the oscillation chamber and in conjunction with other shaped wall surfaces of the oscillation chamber creates a pair of alternately pulsating control vortices for causing the fluid in the power stream to pass alternately to a pair of outlet passages. The vortices alternate both in strength and in a phase opposition to control flow of the jet stream in alternate fashion through the outlet passages. In a preferred embodiment of the invention, the pair of outlet passages are on opposite sides of the barrier member and converge to a common outlet to thereby provide a fan spray as the outlet passages alternate in the passage of the stream of fluid therethrough to the common outlet.

Abstract: In an automobile air flow system, air is forced through an air outlet element or nozzle in a sweeping air stream pattern by an oscillatory member that is supported for air initiated oscillatory movement in the flow path of the air from the source. The oscillatory member is proportioned with respect to the cross-sectional size of the outlet such that at any extreme of its oscillatory movement it does not physically contact any other structural member. In a preferred embodiment, the oscillatory member includes an impingement element and is supported by a spring, the rate of oscillation of the impingement member being directly related to the spring constant and the weight of the impingement member.

Abstract: In an automobile air flow system, air is forced through an air outlet element or nozzle (13, 21, 24) in a sweeping air stream pattern by an oscillating reed or vane member (42) supported solely at the downstream end (43) for air initiated oscillatory movement in the flow path of the air from the source; a weight (41) is on the free, upstream end of the vane and is of a size such that the rate of oscillation is determined by the spring constant of a spring in the vane member and the weight. The oscillating vane (42) is proportioned with respect to the cross-sectional size of the outlet such that at any extreme of its oscillatory movement it does not physically contact any other structural member.

Abstract: A fuel injection system and control valve are disclosed for use with a multi-cylinder engine such as a diesel or proco type engine. The disclosed control valve, which is of the piezoelectric type, controls the fuel injection into the individual cylinders by being connected in fluid circuit between the high pressure pump and distributor which are contained in the pump and distributor assembly. The control valve contains novel features providing improvements in the system.

Abstract: The fluidic oscillator consists of a resonant fluid circuit having a fluid inertance and a dynamic fluid compliance. The inertance is a conduit interconnecting two locations of a chamber on each side of a working fluid jet issuing into one end of the chamber, the inertance conduit serving to transfer working fluid between the two locations. Through one or more output orifices located approximately at the opposite end of the chamber, the fluid exits from a chamber exit region which is shaped to facilitate formation of a vortex (the dynamic compliance) from the entering fluid. The flow pattern in the chamber and particularly the vortex in the chamber exit region provide flow aspiration on one side and surplus of flow on the opposite side of the chamber, which effects accelerate and respectively decelerate the fluid in the inertance conduit such as to cause reversal of the vortex after a time delay given by the inertance.

Abstract: The fluidic oscillator consists of a resonant fluid circuit having a fluid inertance and a dynamic fluid compliance. The inertance is a conduit interconnecting two locations of a chamber on each side of a working fluid jet issuing into one end of the chamber, the inertance conduit serving to transfer working fluid between the two locations. Through one or more output orifices located approximately at the opposite end of the chamber, the fluid exits from a chamber exit region which is shaped to facilitate formation of a vortex (the dynamic compliance) from the entering fluid. The flow pattern in the chamber and particularly the vortex in the chamber exit region provide flow aspiration on one side and surplus of flow on the opposite side of the chamber, which effects accelerate and respectively decelerate the fluid in the inertance conduit such as to cause reversal of the vortex after a time delay given by the inertance.

Abstract: A torsional reed reference fluidic oscillator operating within 0.1% of the desired frequency over a temperature range of -65.degree. to +165.degree.F and an operating pressure of from 1 to 4 psi. The oscillator includes a torsional reed fluidic amplifier and fluidic feedback means for converting output signals from output ports of the amplifier to first and second input signals having a phase relationship for insuring operation of the apparatus as an oscillator. The amplifier is comprised of first, second and third plates, an elongated reed member, first and second torsional members and a tab, all of which are made of material having negligible thermal coefficient of expansion and negligible change in modulus of elasticity over the temperature range. The reed member is positioned within an elongated slot in the first plate, and is fixed thereto by the first and second torsional members, wherein the major axis of the torsional members is perpendicular to the plane and major axis of the reed member.

Abstract: The fluidic oscillator consists of a resonant fluid circuit having a fluid inertance and a dynamic fluid compliance. The inertance is a conduit interconnecting two locations of a chamber on each side of a working fluid jet issuing into one end of the chamber, the inertance conduit serving to transfer working fluid between the two locations. Through one or more output orifices located approximately at the opposite end of the chamber, the fluid exits from a chamber exit region which is shaped to facilitate formation of a vortex (the dynamic compliance) from the entering fluid. The flow pattern in the chamber and particularly the vortex in the chamber exit region provide flow aspiration on one side and surplus of flow on the opposite side of the chamber, which effects accelerate and respectively decelerate the fluid in the inertance conduit such as to cause reversal of the vortex after a time delay given by the inertance.

Abstract: The fluidic oscillator consists of a resonant fluid circuit having a fluid inertance and a dynamic fluid compliance. The inertance is a conduit interconnecting two locations of a chamber on each side of a working fluid jet issuing into one end of the chamber, the inertance conduit serving to transfer working fluid between the two locations. Through one or more output orifices located approximately at the opposite end of the chamber, the fluid exits from a chamber exit region which is shaped to facilitate formation of a vortex (the dynamic compliance) from the entering fluid. The flow pattern in the chamber and particularly the vortex in the chamber exit region provide flow aspiration on one side and surplus of flow on the opposite side of the chamber, which effects accelerate and respectively decelerate the fluid in the inertance conduit such as to cause reversal of the vortex after a time delay given by the inertance.

Abstract: The fluidic oscillator consists of a resonant fluid circuit having a fluid inertance and a dynamic fluid compliance. The inertance is a conduit interconnecting two locations of a chamber on each side of a working fluid jet issuing into one end of the chamber, the inertance conduit serving to transfer working fluid between the two locations. Through one or more output orifices located approximately at the opposite end of the chamber, the fluid exits from a chamber exit region which is shaped to facilitate formation of a vortex (the dynamic compliance) from the entering fluid. The flow pattern in the chamber and particularly the vortex in the chamber exit region provide flow aspiration on one side and surplus of flow on the opposite side of the chamber, which effects accelerate and respectively decelerate the fluid in the inertance conduit such as to cause reversal of the vortex after a time delay given by the inertance.