Fluid oscillator for nozzle assembly for enhanced low-temperature performance

Abstract

A fluidic oscillator circuit for a nozzle assembly is provided that is configured to generate an oscillating spray of fluid from an outlet of the nozzle assembly and improve spray performance of fluids having low temperatures or high viscosity. In one embodiment, an interaction region for the fluidic oscillator circuit is provided that includes an apex protrusion shaped to assist in generating a vortex within the interaction region. In another embodiment, an interaction region for a fluidic oscillator having a power nozzle is provided that includes at least one finger-like protrusion that lengthens the power nozzle to produce a jet of fluid at the interaction region with less diffusion to improve low temperature performance of the fluidic oscillator circuit.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit and priority of U.S. Provisional Patent Application No. 62 / 916,869, filed on October 18, 2019, entitled "Fluidic Oscillator for Nozzle Assembly for Enhanced Low - Temperature Performance", which is hereby incorporated by reference in its entirety.

[0002] The present disclosure generally relates to fluidic oscillators and nozzle assemblies, and methods for manufacturing them to generate an oscillating flow of fluid therefrom. More specifically, the present disclosure relates to fluidic oscillators that can operate at lower temperatures typically associated with more viscous fluids.

Background Art

[0003] Fluidic oscillators are well - known in the prior art for their ability to provide a wide range of liquid spray patterns by periodically deflecting a liquid jet. The operation of most fluidic oscillators is characterized by the periodic deflection of a fluid jet without the use of mechanical moving parts. Thus, an advantage of fluidic oscillators is that they are not subject to the effects of wear and tear that can adversely affect the reliability and operation of other spray devices.

[0004] Examples of fluid oscillators are described in many patents, including, for example, U.S. Patent No. 3,185,166 (Horton and Bowles), U.S. Patent No. 3,563,462 (Bauer), U.S. Patent No. 4,052,002 (Stouffer and Bray), U.S. Patent No. 4,151,955 (Stouffer), U.S. Patent No. 4,157,161 (Bauer), U.S. Patent No. 4,231,519 (Stouffer) reissued as RE33,158, U.S. Patent No. 4,508,267 (Stouffer), U.S. Patent No. 5,035,361 (Stouffer), U.S. Patent No. 5,213,269 (Srinath), U.S. Patent No. 5,971,301 (Stouffer), U.S. Patent No. 6,186,409 (Srinath), and U.S. Patent No. 6,253,782 (Raghu). Each of these references, as well as the references discussed throughout the present application, are hereby incorporated by reference in their entirety.

[0005] In the case of spraying some high viscosity liquids (i.e., 15 - 20 centipoise), the "mushroom oscillator" disclosed in U.S. Patent No. 6,253,782 (Raghu) shown in FIG. 2 has been found to be particularly useful. Raghu describes the operating theory and its dimensional characteristics in detail and has been a major manufacturing option for many years, producing a heavy ended spray distribution with acceptable low temperature performance with a methanol-based fluid at 0°F. However, as the temperature at which the nozzle assembly is expected to function has decreased and additional fluid bases have been introduced, over the years the requirements for spray distribution and low temperature performance have increased. Methanol-based liquids are being gradually replaced by ethanol-based or isopropyl-based liquids. These fluids have significantly higher viscosities at low temperatures than past methanol-based fluids. As described in U.S. Patent No. 7,267,290 and U.S. Patent No. 7,472,848, minor improvements to the basic shape of the fluid oscillator circuit have been proposed and adopted. Both are intended to introduce additional instability into the jets of the high viscosity fluid and help the circuit establish strong oscillations.

[0006] FIG. 1 shows an embodiment of U.S. Patent No. 7,267,290, which teaches incorporating a finger structure behind a dome or mushroom structure to add additional instability and create vortices in the supply of the power nozzle. FIG. 2 shows an embodiment of U.S. Patent No. 7,472,848, which introduces steps at the outlet of the power nozzle to introduce additional recirculation or vortices into the path of the jet to create instability.

[0007] Both of these improvements have produced slightly better cryogenic performance circuits but have some drawbacks. For example, in U.S. Patent No. 7,267,290, the circuit needs to be made slightly longer, which is often not acceptable within the available package space. Also, this configuration may be difficult to tune for low flow rate circuits. U.S. Patent No. 7,472,848 is the most widely adopted of the two, with slightly improved cryogenic performance but no improvement in distribution. As noted, both of these patents describe changes to the circuit outside the interaction region.

[0008] However, it has also been found that when the temperature of such a liquid continues to drop, causing an increase in viscosity (e.g., 25 centipoise), the performance of this type of oscillator can degrade until it no longer provides a jet that essentially oscillates well enough for its spray to be dispersed over the applicable fan angle. This situation is particularly problematic in front windshield washer applications that utilize such fluid oscillators.

[0009] Attempts to change the interaction region to improve the distribution of conventional mushroom circuits led to U.S. Patent No. 7,651,036, which is classified as a "3-jet island" circuit shown in FIG. 6. Here, additional jets and islands are introduced into the interaction region, generating some additional vortices and instabilities. The 3-jet island circuit provides some improvement in improved low-temperature performance and distribution uniformity. This circuit functions very well, but several manufacturing issues arise. For example, when the flow rate of the circuit decreases, the size of the small third island inside becomes very small and is relatively fragile. The very act of assembling the fluid oscillator chip by pushing the chip into the slot (FIG. 5) can damage or break the small island 34. As a result, this 3-jet island circuit can only be reliably used in relatively high-flow nozzles because additional scrap can result in an unintended spray shape. Further, the addition of a third flow channel requires reducing all three flow channels or the power nozzle 24 to maintain the flow rate to specification, resulting in a higher risk of clogging. This requires additional complexity in the filter region, which has its own manufacturing and packaging challenges. Despite much prior art related to fluid oscillators, there remains a need for further technical improvements in the design of fluid oscillators for use in colder environments. The present invention describes further research carried out to improve the circuit while excluding some of the above drawbacks. SUMMARY OF THE INVENTION

[0010] The present disclosure relates to embodiments of a fluid oscillator circuit for a nozzle assembly. In one embodiment, a fluid oscillator circuit is provided that includes a shape defined on a surface that includes at least one inlet configured to receive a fluid flow. An interaction region can be disposed between at least one inlet and an outlet, and the interaction region is defined by a surrounding wall. At least one power nozzle can be configured to receive fluid from at least one inlet and generate a jet of fluid that circulates within the interaction region. An outlet that can be in communication with the interaction region and can be configured to dispense an oscillating spray of fluid in a desired spray pattern. Apex protrusions can be disposed along the surrounding wall of the interaction region and can project inwardly from the surrounding wall. At least one inlet can include a shape that enables fluid communication with the opposite side of the surface on which the shape is defined. The shape can further include an elongate path from at least one inlet to a power nozzle. The interaction region can include a dome or mushroom-shaped region defined by a surrounding wall. The shape can include a first inlet and a second inlet defined on the surface, the first inlet can be in communication with a first power nozzle, and the second inlet can be in communication with a second power nozzle, the first power nozzle and the second power nozzle each being configured to receive fluid from at least one inlet and generate a jet of fluid that circulates within the interaction region, where the apex protrusions can be disposed along the surrounding wall of the interaction region between the first power nozzle and the second power nozzle. The apex protrusions can be disposed equidistant from each of the first power nozzle and the second power nozzle. The apex protrusions are shaped to include an intersection of two rounded or curved surrounding walls of the interaction region that intersect at a point. The apex protrusions can be shaped to include an intersection of two rounded or curved surrounding surfaces of the interaction region that intersect at a point, the point being equidistant from a first power nozzle and a second power nozzle disposed along the interaction region.The vertex protrusion can be configured to direct or stabilize the positions of a plurality of vortices formed by fluid jets from at least one power nozzle within the interaction region, to control the geometric arrangement of the vortices therein, where the plurality of vortices include a left vortex and a right vortex formed by a fluid with an increased measured viscosity for operation at low temperatures. The first inlet and the second inlet can communicate separately with the first power nozzle and the second power nozzle, where the first power nozzle and the second power nozzle are not supplied from a common plenum. The outlet can include an asymmetric or yaw angle configuration.

[0011] In one embodiment, the shape can include a first inlet and a second inlet defined on a surface, where the first inlet communicates with a first power nozzle, and the second inlet communicates with a second power nozzle, and the first power nozzle and the second power nozzle are each configured to receive fluid from at least one inlet and generate a jet of fluid that circulates within the interaction region. A set of finger-like protrusions can be defined adjacent to the outlet of the first power nozzle, a set of finger-like protrusions can be defined adjacent to the outlet of the second power nozzle, and the finger-like protrusions are defined along the peripheral wall of the interaction region.

[0012] In another embodiment, a fluid oscillator circuit for a nozzle assembly is provided that includes a shape defined on a surface configured to receive a fluid flow and includes at least one inlet. The interaction region can be disposed between the at least one inlet and the outlet, and the interaction region is defined by a surrounding wall. At least one power nozzle can be configured to receive fluid from the at least one inlet and generate a jet of fluid that circulates within the interaction region. The outlet may communicate with the interaction region configured to distribute an oscillating spray of fluid in a desired spray pattern therefrom. A set of finger-like protrusions can be defined adjacent to the outlet of the power nozzle along the surrounding wall of the interaction region. The at least one inlet can include a shape that enables fluid communication with the opposite side of the surface on which the shape is defined. The shape can further include an elongated path from the at least one inlet to the power nozzle. The interaction region can include a dome or mushroom-shaped region defined by a surrounding wall. The shape can include a first inlet and a second inlet defined on the surface, the first inlet communicating with a first power nozzle, and the second inlet communicating with a second power nozzle, the first power nozzle and the second power nozzle each being configured to receive fluid from the at least one inlet and generate a jet of fluid that circulates within the interaction region. The apex protrusion can be disposed between the first power nozzle and the second power nozzle along the surrounding wall of the interaction region. The shape can include a first inlet and a second inlet defined on the surface, the first inlet may communicate with the first power nozzle, the second inlet may communicate with the second power nozzle, the first power nozzle and the second power nozzle each being configured to receive fluid from the at least one inlet and generate a jet of fluid that circulates within the interaction region. The first power nozzle can include a first finger-like protrusion extending from a first side of the outlet of the first power nozzle and a second finger-like protrusion extending from a second side of the outlet of the first power nozzle along the surrounding wall of the interaction region. The second power nozzle can include a first finger-like protrusion extending from a first side of the second power nozzle and a second finger-like protrusion extending from a second side of the second power nozzle along the surrounding wall of the interaction region.The finger-like protrusions act to lengthen the power nozzle by extending into the interaction region and are configured to generate therefrom a jet of fluid configured to reduce the likelihood of attachment to the surrounding wall of the interaction region. The first inlet and the second inlet can communicate separately with the first power nozzle and the second power nozzle along the surface, where the first power nozzle and the second power nozzle are not supplied from a common plenum. The outlet can include an asymmetric or yaw angle configuration.

Brief Description of the Drawings

[0013] These as well as other objects and advantages of the present invention will be more fully understood and appreciated by reference to the following more detailed description of the presently preferred exemplary embodiments of the invention in conjunction with the accompanying drawings.

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[0032] Here, exemplary embodiments of the present teachings are referred to in detail, and examples thereof are shown in the accompanying drawings. It should be understood that other embodiments can be utilized and structural and functional changes can be made without departing from the respective scope of the present teachings. Furthermore, the features of the various embodiments can be combined or modified without departing from the scope of the present teachings. Accordingly, the following description is presented for purposes of illustration only and is not intended to limit the various alternatives and modifications that can be made to the illustrated embodiments, which still fall within the spirit and scope of the present teachings. In the present disclosure, any particularity of a specific shape, material, technique, arrangement, etc. is related to the specific examples presented or is merely a general description of such shape, material, technique, arrangement, etc.

[0033] A concept is provided for modifying the interaction region of an enhanced fluid oscillator circuit not explained or taught by the prior art. FIGS. 8A - 8D show various shapes of a fluid oscillator circuit 100 that can be defined within a chip inserted or attached to a nozzle assembly. The shape of the fluid oscillator circuit can be defined on the surface of the chip or on a surface within the nozzle device. The circuit and the surface and / or the nozzle device can be made from a rigid material including a polymer or an alloy that can be formed by any commercial method including molding, additive manufacturing, or other known methods.

[0034] In one embodiment, the fluid oscillator circuit 100 includes at least one inlet 110 for receiving a fluid flow and an outlet 120 for dispensing the oscillating fluid spray in a desired spray pattern therefrom. An interaction region 130 may be disposed between the inlet 110 and the outlet 120 to enable a desired fluid communication therebetween. At least one power nozzle 140 is positioned around the interaction region 130 and can generate jets of fluid received from the inlet 110 and circulating within the interaction region 130. The specific shape of each of the identified elements that make up the fluid oscillator circuit 100 is specified to manipulate the fluid flow therein to produce the desired shape of the oscillating fluid spray. The inlet 110 may have a shape that enables fluid communication with the opposite side of the circuit and then enables an elongated path from the inlet 110 to the power nozzle 140.

[0035] In one embodiment, the interaction region 130 includes a dome or mushroom-shaped region defined by a surrounding wall or surface 132 that includes features for further manipulating the fluid flow therein that are not known or taught by the prior art. In particular, the interaction region 130 may include apex protrusions 150 disposed along the surrounding surface of the interaction region 130 and protruding inwardly from the surrounding. The apex protrusions 150 can be disposed between two opposing power nozzles 140. The apex protrusions 150 can be equidistantly disposed from each of two opposing power nozzles 140, such as the first and second power nozzles 142, 144 as shown in FIG. 8C. The apex protrusions can be shaped to include the intersection of two rounded or curved surrounding surfaces of the interaction region 130 that intersect at a point. The intersection point can be equidistant from two opposing power nozzles 140 disposed along the interaction region 130. The intersection point can be aligned along a central axis 170 as described below.

[0036] The vertex protrusion 150 can be configured to direct or stabilize the position of the vortex 160 formed by the fluid jet within the interaction region 130 to control the geometric arrangement of the vortices therein. FIGS. 8A and 8C show one possible and effective shape of the interaction region including the vertex protrusion 150. In this embodiment, there are separate inlets 110 that communicate separately with opposing power nozzles 140 where the power nozzles are not supplied from a common plenum. However, the present disclosure contemplates that the addition of the vertex protrusion 150 can be used in various types of fluid oscillator circuit types and can also be used in other types of fluid oscillator circuits such as those that utilize a common plenum to receive fluid from the inlets.

[0037] FIGS. 8A and 8C show a vertex protrusion 150 added to the interaction region 130 to help form left and right vortices 160 within the interaction region 130 when fluid is introduced therein from the power nozzles 140. FIG. 7 is provided to identify how the fluid flow passes through an interaction region without such a vertex protrusion of a known type. Further, FIGS. 8B and 8D are provided as reference frames to show how the fluid flow can be manipulated by the addition of the vertex protrusion 150 (shown by FIGS. 8A and 8C) to provide coherence of the fluid flow. In particular, the newly disclosed interaction region 130 having the vertex protrusion 150 is particularly beneficial when the fluid has an increased measured viscosity for operation at low temperatures.

[0038] For example, the addition of the vertex protrusion 150 enables a plurality of upper vortices 160 along either side of the vertex protrusion 150 as it is dispensed from the outlet 120 during the oscillatory cycle of the fluid flow. Since the spray of fluid from the outlet 120 is angled, this consistency in vortex generation is particularly seen in FIG. 8A and, when compared to FIG. 8C, the oscillation of the spray of fluid from the outlet 120 is directed outward along an axis generally aligned along the central axis 170 of the circuit 100. Notably, since the fluid spray is generated along the entire fan spray shape, the vortices 160 appear to have a generally consistent shape of the fluid flow during the oscillatory cycle.

[0039] Conversely, FIGS. 8B and 8D show vortices 160 of an inconsistent shape with large upper vortices and small upper vortices present in FIG. 8B due to the angled spray of fluid from the outlet. Further, FIG. 8D shows vortices 160 of an inconsistent shape compared to the interaction region shown by FIG. 8B since the oscillation of the spray of fluid from the outlet 120 is directed outward along an axis aligned along the central axis 170 of the circuit.

[0040] The sample circuit was fabricated in the shape of the fluid oscillator circuit 100 including the vertex protrusion 150. It was tested to produce a nominal fan of approximately 53 degrees with a uniform spray pattern very similar to the above-described three-jet island circuit. Its flow rate was approximately 500 ml / min at 22 PSI. The low-temperature performance was very good with a 50% methanol solution at 0°F and it was confirmed to have a low-temperature fan of approximately 35 degrees at 5 PSI and 40 degrees at 6 PSI. In particular, a similar three-jet island circuit was found to have a low-temperature fan of approximately 30 degrees at 7 PSI, 32 degrees at 10 PSI, and 40 degrees at 15 PSI. This embodiment provides a significant improvement compared to the prior art since the fan recovers much faster and enables a larger nominal fan angle during the oscillatory cycle of the fluid at low temperatures.

[0041] In another embodiment, as shown in FIG. 9A, a fluid oscillator circuit 100 is provided that has many of the same features as described above, including an improved discovered interaction region. This embodiment includes a set of finger-like protrusions 200 defined adjacent to the outlet of the power nozzle 140. The finger-like protrusions 200 can extend from either side of the power nozzle 140 and serve to lengthen the power nozzle without increasing the overall size of the fluid oscillator circuit or chip. The addition of such finger-like protrusions 200 lengthens the lumen of the power nozzle 140 such that when fluid flows therethrough, a jet with less diffusion (i.e., less wall attachment) is generated. The generated jet having reduced diffusion within the interaction results in an increase in the active / unstable fluid under low temperature and / or high viscosity conditions. The finger-like protrusions 200 can generate a stronger jet / flow of fluid at the center of the interaction region 130. The resulting fluid spray from the outlet 120 has been found to be a more uniform fan than a conventional mushroom-shaped interaction region without such finger-like protrusions. FIG. 9A shows one possible embodiment of this feature having an outlet 120 with an asymmetric or yaw angle configuration and a plurality of inlets 110. However, the present disclosure contemplates that the finger-like protrusions 200 can be adapted for use in all types of fluid oscillator circuits known to exist, and the present disclosure is not limited in this regard.

[0042] For comparison, a circuit that is a conventional style mushroom (the one on the left side of FIGS. 12A or 12B) has the same low temperature performance as the new circuit (FIG. 9A). However, the spray pattern of the old mushroom circuit has a heavy end and is not suitable for some applications such as rear window sprays in automobiles. The 3-jet island circuit (FIG. 6) results in a desirable uniform fluid output spray fan but lacks sufficient low temperature performance and results in even less desirable low temperature performance than the old mushroom circuit.

[0043] The finger-like projection feature 200 (FIG. 9A) extends the power nozzle and acts to improve the low-temperature performance of the fluid oscillator circuit in addition to the inlet 110 having a vertical supply (FIGS. 8A-8D, 9A and 9B). The combination of the vertical supply 110 and the finger-like projection 200 results in improved low-temperature performance with an output fan spray that has a less heavy end. Further, the vertex projection 150 (FIG. 12B) helps to make the spray pattern more uniform without degrading the low-temperature performance. The short distance between the vertical supply (inlet 110) and the outlet of the power nozzle 140 helps to improve the low-temperature performance, but has been found to add more manufacturing risk.

[0044] FIG. 9B shows another embodiment of the present application including the finger-like projection 200 and the top projection 150 having a throat outflow outlet with an asymmetric yaw angle. Such an angle can be about 15 degrees, and this disclosure is not limited to such a shape. This particular embodiment provides a subtle improvement in the behavior of the fluid within the nozzle assembly and enables the fluid spray and low-temperature performance that results in the desired reduction of the "heavy-end" spray fan shape.

[0045] A sample circuit with finger-like projections was found to produce a fan of about 60 degrees at a flow rate of 735 ml / min at 18 PSI at room temperature (warm temperature). This circuit was also found to exhibit low-temperature performance of a 40-degree fan at 4 PSI and a 50-degree fan at 5 PSI at 0°F of a methanol fluid such as a 50% methanol solution. This circuit was also found to exhibit low-temperature performance of a 40-degree fan at 7 PSI and a 50-degree fan at 8 PSI at 0°F of an ethanol fluid such as a 50% ethanol fluid solution. Although FIG. 9 shows a biased spray circuit, it is equally applicable to a circuit without bias. FIG. 4 shows a prior art mushroom-type fluid oscillator circuit with a biased configuration for comparison. The circuit of FIG. 4 includes a 60-degree fan at room temperature (warm temperature) and a flow rate of 810 ml / min at 18 PSI, but its low-temperature performance of the methanol fluid shows a 20-degree fan at 20 PSI and a 40-degree fan at 30 PSI.

[0046] In this embodiment of the interaction region enhancement, the fluid oscillator circuit exhibits an increase in low temperature performance beyond that of a similar mushroom circuit.

[0047] The following images illustrate the differences in spray distribution and droplet size between the new configuration (Figure 10) and a standard mushroom-type fluid oscillator circuit known in the art (Figure 11). Here, the spray fan generated by the fluid oscillator circuit of Figure 10 includes a relatively large droplet size where the ends of the spray fan are only slightly heavier ends. In contrast, the conventional mushroom-style fluid oscillator shown in Figure 11 produces a spray fan with a relatively small droplet size, where the ends of the spray fan are reconsidered to have very heavy ends.

[0048] Figures 12A and 12B show embodiments of an improved fluid oscillator circuit design disclosed by this application as they are distinguished from circuits known in the art. The known circuit NC is shown on the left, and an embodiment of the new fluid oscillator circuit 100 is shown on the right. These fluid oscillator designs have been confirmed to improve the low temperature performance of the fluid oscillator circuit, generate higher speeds, and produce a more uniform spray.

[0049] Figure 12A shows an embodiment including a set of finger-like protrusions 200 defined adjacent to the outlet of the power nozzle 140. The finger-like protrusions 200 can extend from either side of the power nozzle 140 and act to lengthen the power nozzle without increasing the overall size of the fluid oscillator circuit or chip. As distinguished from Figure 9, Figure 12A shows one possible embodiment of this feature having a symmetric configuration with an outlet 120 and a single inlet 110. However, this disclosure contemplates that the finger-like protrusions 200 can be adapted for use in all types of fluid oscillator circuits known to exist, and this disclosure is not limited in this regard.

[0050] FIG. 12B shows an embodiment including vertex protrusions 150 extending within the interaction region 130 of the circuit. The vertex protrusions 150 added to the interaction region 130 help to form left and right vortices within the interaction region 130 when fluid is introduced into it from the power nozzle 140. In particular, the newly disclosed interaction region 130 with vertex protrusions 150 is particularly beneficial when the fluid has an increased measured viscosity for operation at low temperatures.

[0051] FIG. 13 is provided to show that as the temperatures of methanol and ethanol fluids decrease, their viscosities increase, and thus there is a need to develop improvements to the sprays generated by fluid oscillators for fluids with decreasing temperatures and increasing viscosities.

[0052] Embodiments of the present teachings are shown in the accompanying drawings and described in the foregoing detailed description, but the present teachings are not limited to the disclosed embodiments only, and it should be understood that the present teachings described herein are capable of numerous rearrangements, modifications, and substitutions without departing from the scope of the following claims. The following claims are intended to cover all modifications and variations as long as they are within the scope of the claims or their equivalents.

Claims

Claim 1 A fluid oscillator circuit for a nozzle assembly, comprising a circuit member defining first and second opposing planes, at least one inlet passing through the circuit member to enable fluid communication through the circuit member, an interaction region (i) formed in the first plane and (ii) defined by an upstream peripheral wall disposed opposite two downstream peripheral wall portions, an outlet (i) defined by respective opposing end portions of the two downstream peripheral wall portions, (ii) disposed along a downstream end in the first plane, and (iii) configured to distribute a vibrating fan spray in a plane coinciding with the first plane, first and second power nozzles, each power nozzle (i) being formed in the first plane, (ii) being fluidly connected to the at least one inlet, and (iii) being defined by respective end portions of the upstream peripheral wall and one of the downstream peripheral wall portions, wherein the upstream peripheral wall has a dome or mushroom shape with a vertex protrusion extending towards the outlet, the vertex protrusion being disposed between the first power nozzle and the second power nozzle and being equidistant from the first power nozzle and the second power nozzle along the upstream peripheral wall so as to interrupt the upstream peripheral wall, and being shaped to include an intersection of two rounded or curved peripheral surfaces of the upstream peripheral wall. A fluid oscillator circuit. Claim 2 The fluid oscillator circuit according to claim 1, wherein the vertex protrusion has an intersection aligned along a central axis extending along the length of the first plane. Claim 3 The fluid oscillator circuit according to claim 1 or 2, wherein the vertex protrusion has a V shape and each of the two rounded or curved peripheral surfaces has a C shape. Claim 4 The fluid oscillator circuit according to claim 2 or claim 3 dependent on claim 2, wherein the outlet is disposed on the central axis extending along the length of the first plane. Claim 5 The fluid oscillator circuit according to any one of claims 2, claim 3 dependent on claim 2, and claim 4, wherein each of the downstream peripheral wall portions has a C shape. Claim 6 The fluid oscillator circuit according to claim 5, wherein each of the downstream peripheral wall portions includes an inner end portion defining an opposing side portion of the outlet. Claim 7 The fluid oscillator circuit according to claim 6, wherein each of the inner end portions includes a linear wall portion aligned perpendicular to the central axis. Claim 8 The fluid oscillator circuit according to claim 2 or 4, wherein the two downstream peripheral wall portions form a mirror image about the central axis.

9. The fluid oscillator circuit according to claim 2, claim 3 dependent on claim 2, and any one of claims 4 to 8, wherein the first and second inlets are provided on both sides of the central axis, the first inlet supplies only to the first power nozzle, and the second inlet supplies only to the second power nozzle.

10. The fluid oscillator circuit according to any one of claims 1 to 9, wherein at least one end portion of the upstream peripheral wall defines a finger-like projection, and the finger-like projection of the upstream peripheral wall is configured to extend one power nozzle to the central portion of the interaction region.

11. The fluid oscillator circuit according to claim 10, wherein an end portion of the downstream peripheral wall portion defining the one power nozzle has a finger-like projection, and the finger-like projection of the downstream peripheral wall portion is configured to extend the one power nozzle to the central portion of the interaction region.

12. The fluid oscillator circuit according to claim 11, wherein the second power nozzle is configured to have the same finger-like projection at each end portion of the upstream peripheral wall and the downstream peripheral wall portion as compared with the first power nozzle.

13. The fluid oscillator circuit according to any one of claims 1 to 12, wherein the oscillating fan spray has an angle with a width of at least 35 degrees in a plane.

14. The fluid oscillator circuit according to any one of claims 1 to 12, wherein the oscillating fan spray has an angle with a width of up to at least 60 degrees in a plane.

15. The fluid oscillator circuit according to any one of claims 1 to 14, wherein the outlet has an asymmetric configuration or is arranged at a yaw angle with respect to the downstream end.

16. The fluid oscillator circuit according to any one of claims 1 to 15, wherein the first and second power nozzles are not supplied from a common plenum.

17. The fluid oscillator circuit according to any one of claims 1 to 16, wherein the vertex projection is arranged equidistantly from each end portion of the upstream peripheral wall.

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