Oscillating nozzle with complex feedback channel regulation and working method

Abstract

The present application belongs to the technical field of oscillating nozzle, and particularly relates to an oscillating nozzle with a composite feedback channel regulation and a working method. The oscillating nozzle comprises an inlet section, a main cavity, an outlet section, and a feedback channel, two ends of the feedback channel being in communication with the main cavity; a channel wall of the feedback channel is a sinusoidal wall surface to form a sinusoidal channel for continuously modulating the feedback pressure disturbance along the length direction; a bifurcated partition is further arranged in the feedback channel, the bifurcated partition extending along the length direction of the feedback channel to separate the sinusoidal channel into a main feedback channel with a large flow area and a secondary feedback channel with a small flow area; the main feedback channel and the secondary feedback channel have different feedback pressure propagation time scales. The present application simultaneously sets the sinusoidal wall surface and the bifurcated partition in the feedback channel of the oscillating nozzle, and the two cooperatively form a composite multi-scale feedback mechanism to improve the low-pressure oscillation performance and the oscillation stability in all working conditions.

Description

Technical Field

[0001] This invention belongs to the field of oscillating nozzle technology, specifically relating to an oscillating nozzle with composite feedback channel control and its working method. Background Technology

[0002] Existing oscillating nozzles typically consist of a main chamber, an outlet channel, and two side feedback channels. The feedback channels are mostly straight-walled, single-cavity structures, meaning feedback pressure disturbances propagate along a single straight path with no continuous modulation along the flow, a fixed time scale, and limited adjustment freedom. Under low-pressure conditions, insufficient feedback strength leads to difficulty initiating oscillation or even the inability to form stable oscillations. Under high-pressure conditions, feedback delay mismatch results in unstable oscillations. While feedback channels using bifurcated baffles can achieve dual-time-scale feedback, the walls remain straight, lacking continuous modulation along the flow path. While corrugated wall flow paths can achieve local pressure modulation, they haven't yet synergized with the oscillating nozzle's feedback mechanism and hierarchical bifurcation. These single control methods limit the time scale and spectral coverage of the feedback mechanism, making it difficult to simultaneously meet the requirements of rapid initiation and stable oscillation across a wide range of operating conditions. If the nozzle has difficulty initiating oscillation or the oscillation rhythm is unstable, it will affect the spatial distribution and local mixing uniformity of the working medium, which is detrimental to combustion organization and stable system operation. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide an oscillating nozzle with composite feedback channel control and its operating method. By simultaneously setting a sinusoidal waveform wall and a bifurcated baffle in the feedback channel of the oscillating nozzle, the sinusoidal waveform wall provides distributed continuous modulation along the path, and the bifurcated baffle provides dual time-scale hierarchical feedback. The two work together to form a composite multi-scale feedback mechanism to improve low-voltage oscillation performance and oscillation stability under all operating conditions.

[0004] The present invention provides an oscillating nozzle with composite feedback channel control, comprising an inlet section, a main cavity, an outlet section, and feedback channels symmetrically arranged on both sides of the main cavity, wherein the two ends of the feedback channels are respectively connected to the main cavity; The channel wall of the feedback channel is a sinusoidal waveform wall surface, which undulates periodically along the length of the feedback channel to form a sinusoidal waveform channel for distributed continuous modulation of the feedback pressure disturbance along the path. The feedback channel is also provided with a bifurcated partition, which extends along the length of the feedback channel and divides the inside of the sine wave channel into a main feedback channel with a large flow area and a secondary feedback channel with a small flow area. The primary feedback channel and the secondary feedback channel have different feedback pressure propagation timescales.

[0005] Furthermore, the sinusoidal waveform wall has an undulation period of 1.5 to 2 complete wavelengths along the length of the feedback channel, and the amplitude is 10% to 20% of the width of the feedback channel.

[0006] Furthermore, the wavelength of the sinusoidal waveform wall is 8~12mm, and the effective length of the feedback channel is 15~25mm.

[0007] Furthermore, the sinusoidal waveform wall is disposed in the first two-thirds of the feedback channel inlet side; The rear third of the feedback channel's outlet side is either a straight wall or a slightly expanded form.

[0008] Furthermore, the bifurcated partition is arranged in the second peak to trough interval of the sinusoidal waveform wall, and the extension dimension of the bifurcated partition in the feedback channel width direction is 30% to 50% of the feedback channel width.

[0009] Furthermore, the bifurcated partition adopts a smooth transition design on the inlet side near the main cavity.

[0010] Furthermore, the bifurcation angle of the bifurcation partition is 15°~30°.

[0011] Furthermore, the amplitude of the sinusoidal waveform wall gradually changes along the length of the feedback channel: the amplitude of the sinusoidal waveform wall at the inlet side of the feedback channel is the first value, the amplitude in the middle section is the second value, and the amplitude at the outlet side is the third value, with the first value > the second value > the third value, and the third value approaching zero.

[0012] Furthermore, the feedback channel is equipped with multiple bifurcated partitions to divide the sinusoidal waveform channel into two or more levels of multi-level feedback channels, forming a multi-timescale feedback mechanism.

[0013] The present invention also provides a method for fluid oscillation control using the above-mentioned oscillating nozzle with composite feedback channel control, comprising the following steps: After the main jet enters the main cavity through the inlet section, a portion of the fluid enters the feedback channel; The fluid, within the sinusoidal channel formed by the sinusoidal wall, alternately experiences cross-sectional expansion at the crests and cross-sectional contraction at the troughs, and is subjected to distributed continuous pressure modulation, forming a feedback pressure disturbance containing multiple frequency components. The feedback pressure disturbance, under the separation effect of the bifurcated partition, enters the main feedback channel and the secondary feedback channel respectively, forming a fast main feedback signal and a delayed secondary feedback signal with different propagation times; The main feedback signal and the secondary feedback signal return to the other side of the main cavity through the feedback channel, and the combined feedback pressure of multiple time scales acts on the main jet, driving the main jet to deflect and switch periodically in the main cavity, and finally ejected from the outlet section to form a periodic oscillating jet.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: I. This invention introduces both a sinusoidal waveform wall and a bifurcated partition within the feedback channel, forming a composite feedback channel structure that combines distributed continuous modulation with centralized hierarchical control. The sinusoidal waveform wall provides continuously varying micro-timescale modulation along the path, while the bifurcated partition provides path separation for both fast and slow macro-timescales. The two work synergistically within the same space to form a composite feedback mechanism covering a wide frequency band and multiple timescales. This mechanism allows for active control of the propagation path, timescale, and spectral characteristics of feedback pressure disturbances, overcoming the technical shortcomings of existing straight-walled single-cavity feedback channels, such as straight propagation paths, fixed timescales, and a single spectrum.

[0015] Second, under low operating pressure conditions, the local expansion effect at the crest of the sinusoidal waveform wall creates a local low-pressure zone within the feedback channel, which facilitates the intake of more fluid from the main cavity to participate in the feedback cycle, increasing the feedback flow rate. The delay path of the secondary feedback channel provides additional pressure accumulation time, enhancing the total energy of the feedback signal. The distributed continuous modulation of the sinusoidal waveform wall ensures sufficient spectral richness of the feedback signal, while the dual-timescale path separation of the bifurcated baffle ensures that the feedback energy arrives at the correct position at the correct time. The synergy of these two factors makes it easier for the main jet to overcome initial inertia and achieve initial deflection and switching, effectively improving low-pressure start-up performance and reducing the stable operating pressure drop threshold of the nozzle.

[0016] Third, during the oscillation maintenance process, the periodic pressure modulation generated along the sinusoidal wall surface gives the feedback signal pulse sequence characteristics, avoiding the overshoot or undershoot problems that may occur with a single pulse in traditional straight-wall channels. The dual-timescale path separation generated by the bifurcated baffle gives the feedback process inherent redundancy—the main feedback channel provides fast direct feedback to ensure timely switching response, while the secondary feedback channel provides delayed auxiliary feedback to enhance the robustness of the feedback process. The micro-timescale modulation of the sinusoidal wall surface smooths the local fluctuations of the feedback signal, while the macro-timescale separation of the bifurcated baffle stabilizes the overall oscillation rhythm. The superposition of these two factors transforms the internal flow of the nozzle from single-timescale instability to multi-timescale coordinated control, improving the repeatability of the oscillation period and the switching stability, and overcoming the problem that traditional structures cannot simultaneously achieve oscillation initiation and oscillation stability over a wide range of operating conditions.

[0017] Fourth, the aforementioned composite multi-scale feedback control effect can continuously improve the spatial distribution characteristics of the working medium. The periodic oscillation of the oscillating jet covers a wider flow field range, and the multi-frequency component feedback signal induced by the sinusoidal wall makes the jet oscillation rhythm richer, enhances the mixing ability between the mainstream and the surrounding medium, expands the effective action area, improves local mixing uniformity, and is beneficial to subsequent combustion organization and stable system operation.

[0018] 5. The sinusoidal waveform wall surface adopts a continuous curvature transition, which provides a smoother flow disturbance than abrupt obstacles, reducing the risk of strong separation and additional energy loss while maintaining modulation effectiveness. The bifurcation baffle adopts a thin plate structure with a smooth transition at the front end, limiting its obstructive effect on the flow. The overall structure is a "non-intrusive" improvement scheme. Neither the sinusoidal waveform wall surface nor the bifurcation baffle changes the flow state of the main cavity; they only act within the feedback channel, achieving composite feedback control while also taking into account pressure loss control.

[0019] VI. The sinusoidal wave wall surface can be achieved through CNC machining or 3D printing. The bifurcated partition can be achieved by adding simple processes to the traditional machining process. The structural complexity is relatively low and it has good engineering feasibility.

[0020] VII. The sinusoidal waveform wall and the bifurcation baffle each possess independent degrees of adjustment freedom. By changing the wavenumber and amplitude of the sinusoidal waveform wall, the intensity and spectral coverage of the distributed continuous modulation can be adjusted; by changing the extension length and bifurcation angle of the bifurcation baffle, the flow area ratio and the difference between the two time scales between the primary and secondary feedback channels can be adjusted. These two sets of parameters can be optimized independently or matched collaboratively, enabling the nozzle structure to adaptively adjust its feedback characteristics within a certain operating range, providing greater freedom for nozzle design and adaptation under different operating conditions. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] In the diagram, 1-inlet section; 2-main cavity; 3-outlet section; 4-feedback channel; 5-sine wave wall; 6-bifurcation partition; 7-main feedback channel; 8-secondary feedback channel. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0025] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0026] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0028] like Figure 1 As shown, the present invention provides an oscillating nozzle with composite feedback channel control, including an inlet section 1, a main cavity 2, an outlet section 3, and feedback channels 4 symmetrically arranged on both sides of the main cavity 2. The two ends of the feedback channels 4 are respectively connected to the main cavity 2. This constitutes the basic flow loop of the oscillating nozzle: after the main jet enters the main cavity 2 from the inlet section 1, it forms a periodic switching under the action of expansion, deflection and feedback coupling, and finally ejects from the outlet section 3 to form an oscillating jet. The two feedback channels 4 are symmetrically arranged to transmit the pressure disturbance on one side of the main cavity 2 to the other side, providing feedback drive for jet switching.

[0029] The feedback channel 4 has a sinusoidal waveform wall 5, which undulates periodically along the length of the feedback channel 4 to form a sinusoidal waveform channel for distributed continuous modulation of the feedback pressure disturbance along the path. Both ends of the feedback channel 4 are connected to the main cavity 2, with the side closer to the outlet section 3 being the inlet side and the side closer to the inlet section 1 being the outlet side. The sinusoidal waveform wall 5 has an inner sinusoidal waveform wall closer to the main cavity 2 and an outer sinusoidal waveform wall further away from the main cavity 2. Both the inner and outer sinusoidal waveform walls undulate periodically along the length of the feedback channel 4, together forming the sinusoidal waveform channel. The sinusoidal waveform wall 5 causes the fluid to experience periodic cross-sectional expansion and contraction during propagation—the cross-section expands, the velocity decreases, and the pressure increases at the crests, while the cross-section contracts, the velocity increases, and the pressure decreases at the troughs—thus forming a periodic pressure gradient along the path within the feedback channel 4. This structure simultaneously generates three synergistic effects: First, the local pressure modulation effect continuously modulates the feedback pressure disturbance along the path, making the feedback signal no longer a single pulse but a pulse sequence with multiple frequency components; second, the effective path extension effect, the actual propagation path of the fluid along the sinusoidal wall 5 is greater than the straight-line distance, naturally increasing the feedback delay without increasing the external dimensions of the cavity; third, the multi-reflection point effect, each peak and trough constitutes a potential local reflection point, making the feedback signal form a pulse sequence characteristic, avoiding the overshoot or undershoot problems that may be caused by a single pulse in a traditional straight-wall channel.

[0030] The feedback channel 4 is further equipped with a bifurcated baffle 6, which extends along the length of the feedback channel 4, dividing the sinusoidal waveform channel into a main feedback channel 7 with a large flow area and a secondary feedback channel 8 with a small flow area. The bifurcated baffle 6 forms a hierarchical structure similar to the main trunk and branches of a leaf vein: the main feedback channel 7 with a large flow area undertakes the main function of pressure disturbance propagation, allowing fluid to pass through quickly and providing a fast main feedback path; the secondary feedback channel 8 with a small flow area provides auxiliary pressure buffering and delayed feedback functions, requiring fluid to form an additional path around the end of the baffle, providing a delayed secondary feedback path. The two paths remain connected before merging at the end of the bifurcated baffle 6, allowing the two feedback signals to couple and interfere during propagation, forming a complex feedback waveform.

[0031] The main feedback channel 7 and the secondary feedback channel 8 have different feedback pressure propagation time scales. The main feedback channel 7 has a large flow area, large flow rate, and fast flow velocity, so the feedback pressure disturbance propagates in the main feedback channel 7 for a shorter time and arrives at the other side of the main cavity 2 first in the time dimension. The secondary feedback channel 8 has a small flow area, small flow rate, and slow flow velocity, so the feedback pressure disturbance propagates in the secondary feedback channel 8 for a longer time and arrives later in the time dimension. By adjusting the position of the bifurcation partition 6, the time difference between the main feedback channel 7 and the secondary feedback channel 8 can be actively controlled: if the main feedback channel 7 is placed on the outer side away from the main cavity 2, the propagation path of the main feedback channel 7 is relatively longer, while the propagation path of the secondary feedback channel 8 is relatively shorter, the time difference between the two channels is reduced, and the two feedback signals tend to arrive at the same time, which can reduce the interference of the small-area flow of the secondary feedback channel 8 on the main feedback signal and improve the feedback coordination; conversely, if the main feedback channel 7 is placed on the inner side closer to the main cavity 2, the main feedback path is short and the secondary feedback path is long, the time difference is increased, and a distinct time-sequential feedback is formed. This dual-time-scale feedback mechanism works synergistically with the distributed continuous modulation of the sinusoidal waveform wall 5 in the same feedback channel 4 space: the sinusoidal waveform wall 5 provides micro-time-scale modulation that changes continuously along the path, "pre-modulating" the feedback signal to give it sufficient spectral richness and ordered structure; on this basis, the bifurcation partition 6 provides path separation of fast and slow macroscopic time scales, "re-separating" the modulated feedback signal. The two superpositions form a composite feedback control system covering a wide frequency band and multiple time scales, which transforms the internal flow of the nozzle from instability of a single time scale to coordinated control of multiple time scales. The micro-time scale modulation of the sinusoidal waveform wall 5 smooths the local fluctuations of the feedback signal, while the macro-time scale separation of the bifurcation partition 6 stabilizes the overall oscillation rhythm.

[0032] During the oscillation initiation phase, the local expansion effect at the peak of the sinusoidal wall 5 creates a local low-pressure zone within the feedback channel 4, which facilitates the intake of more fluid from the main cavity 2 to participate in the feedback cycle, increasing the feedback flow rate. Simultaneously, the delay path of the secondary feedback channel 8 provides additional pressure accumulation time, enhancing the total energy of the feedback signal. The "pre-modulation" of the sinusoidal wall 5 ensures sufficient spectral richness in the feedback signal, while the "re-separation" of the bifurcated partition 6 ensures that the feedback energy arrives at the correct position at the correct time. Together, these two mechanisms make it easier for the main jet to overcome initial inertia and achieve the first deflection and switching, thereby improving low-pressure initiation performance and reducing the stable operating pressure drop threshold of the nozzle.

[0033] During the full-cycle oscillation maintenance phase, the periodic pressure modulation generated along the sinusoidal wall 5 causes the feedback signal to exhibit pulse sequence characteristics. The dual-time-scale path separation generated by the bifurcation partition 6 provides inherent redundancy in the feedback process—the main feedback channel 7 provides rapid direct feedback to ensure timely switching response, while the secondary feedback channel 8 provides delayed auxiliary feedback to enhance the robustness of the feedback process. This process helps improve the repeatability of the oscillation cycle and the stability of switching, and also improves the consistency of the spatiotemporal distribution of the outlet jet.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows: I. This invention introduces both a sinusoidal waveform wall 5 and a bifurcated partition 6 within the feedback channel 4, forming a composite feedback channel structure that combines distributed continuous modulation and centralized hierarchical control. The sinusoidal waveform wall 5 provides continuously varying micro-timescale modulation along the path, while the bifurcated partition 6 provides path separation for both fast and slow macro-timescales. The two work synergistically within the same space to form a composite feedback mechanism covering a wide frequency band and multiple timescales. This mechanism allows for active control of the propagation path, timescale, and spectral characteristics of feedback pressure disturbances, overcoming the technical shortcomings of existing straight-walled single-cavity feedback channels, such as straight propagation paths, fixed timescales, and a single spectrum.

[0035] Second, under low operating pressure conditions, the local expansion effect at the peak of the sinusoidal waveform wall 5 creates a local low-pressure zone within the feedback channel 4, which facilitates the intake of more fluid from the main cavity 2 to participate in the feedback cycle, increasing the feedback flow rate. The delay path of the secondary feedback channel 8 provides additional pressure accumulation time, enhancing the total energy of the feedback signal. The distributed continuous modulation of the sinusoidal waveform wall 5 ensures sufficient spectral richness of the feedback signal, while the dual-time-scale path separation of the bifurcation baffle 6 ensures that the feedback energy arrives at the correct position at the correct time. The synergy of these two factors makes it easier for the main jet to overcome initial inertia and achieve initial deflection and switching, effectively improving low-pressure start-up performance and reducing the stable operating pressure drop threshold of the nozzle.

[0036] Third, during the oscillation maintenance process, the periodic pressure modulation generated along the sinusoidal wall surface 5 makes the feedback signal exhibit pulse sequence characteristics, avoiding the overshoot or undershoot problems that may be caused by a single pulse in the traditional straight-wall channel; the dual time-scale path separation generated by the bifurcated baffle 6 gives the feedback process inherent redundancy—the main feedback channel 7 provides fast direct feedback to ensure timely switching response, while the secondary feedback channel 8 provides delayed auxiliary feedback to enhance the robustness of the feedback process. The micro-time-scale modulation of the sinusoidal wall surface 5 smooths the local fluctuations of the feedback signal, and the macro-time-scale separation of the bifurcated baffle 6 stabilizes the overall oscillation rhythm. The superposition of the two transforms the internal flow of the nozzle from single-time-scale instability to multi-time-scale coordinated control, improving the repeatability of the oscillation period and the switching stability, and overcoming the problem that traditional structures cannot simultaneously achieve oscillation initiation and oscillation stability over a wide operating range.

[0037] IV. The aforementioned composite multi-scale feedback control effect can continuously improve the spatial distribution characteristics of the working medium. The periodic oscillation of the oscillating jet covers a wider flow field range, and the multi-frequency component feedback signal induced by the sinusoidal wall surface 5 enriches the jet oscillation rhythm, enhances the mixing ability between the mainstream and the surrounding medium, expands the effective action area, improves local mixing uniformity, and is beneficial to subsequent combustion organization and stable system operation.

[0038] 5. The sinusoidal waveform wall 5 adopts a continuous curvature transition, which provides a smoother flow disturbance than abrupt obstacles, reducing the risk of strong separation and additional energy loss while maintaining modulation effectiveness. The bifurcation baffle 6 adopts a thin plate structure with a smooth transition at the front end, limiting its flow obstruction effect. The overall structure is a "non-intrusive" improvement scheme. Neither the sinusoidal waveform wall 5 nor the bifurcation baffle 6 changes the flow state of the main cavity 2, acting only within the feedback channel 4, achieving composite feedback control while also taking into account pressure loss control.

[0039] 6. The sinusoidal wave wall surface 5 can be realized by CNC machining or 3D printing. The bifurcated partition 6 can be realized by adding simple processes on the basis of traditional machining. The structural complexity is relatively low and it has good engineering feasibility.

[0040] VII. The sinusoidal waveform wall 5 and the bifurcation partition 6 each possess independent degrees of adjustment freedom. By changing the wavenumber and amplitude of the sinusoidal waveform wall 5, the intensity and spectral coverage of the distributed continuous modulation can be adjusted; by changing the extension length and bifurcation angle of the bifurcation partition 6, the flow area ratio and the difference between the two time scales between the primary and secondary feedback channels can be adjusted. The two sets of parameters can be optimized independently or matched collaboratively, enabling the nozzle structure to adaptively adjust its feedback characteristics within a certain operating range, providing more degrees of freedom for nozzle design and adaptation under different operating conditions.

[0041] In one embodiment, the sinusoidal waveform wall 5 has an undulation period of 1.5 to 2 complete wavelengths along the length of the feedback channel 4, and the amplitude is 10% to 20% of the width of the feedback channel 4.

[0042] The functional objective of the sinusoidal waveform wall 5 is to continuously modulate the feedback pressure disturbance along the flow path, forming a pulse sequence with multiple frequency components rather than a single pulse. When the wave number is less than one complete wavelength, the fluid undergoes only one incomplete expansion-contraction process within the feedback channel 4. The pressure gradient along the flow path changes monotonically, making it impossible to establish a periodic modulation rhythm. The feedback signal still maintains a single pulse characteristic, and the multi-reflection point effect cannot be formed. When the wave number exceeds 2.5 complete wavelengths, the fluid needs to repeatedly experience alternating switching between cross-sectional expansion and contraction. Under the action of multiple adverse pressure gradients, the boundary layer accumulates a tendency to separate, and the structural order of the modulation signal along the flow path is gradually destroyed. At the same time, the accumulated flow loss caused by over-modulation will offset the modulation gain. A fluctuation period of 1.5 to 2 complete wavelengths allows the fluid to undergo a sufficient number of modulation cycles within the feedback channel 4 to form a pulse sequence characteristic, while controlling the risk of boundary layer separation within a recoverable range for a single cycle. The orderliness and sufficiency of the modulation process are thus balanced. In terms of amplitude: the amplitude determines the magnitude of the expansion of the wave crest and the contraction of the wave trough, directly affecting the intensity of the local pressure gradient. When the amplitude is less than 10% of the width of feedback channel 4, the cross-sectional changes at the crest and trough are too weak, and the resulting local pressure difference is insufficient to effectively modulate the feedback pressure disturbance. The pressure gradient along the path is almost flat, and the sinusoidal wall 5 is practically useless. When the amplitude is greater than 20% of the width of feedback channel 4, the cross-section at the trough contracts excessively, the fluid accelerates significantly, the local velocity peak is too high, and the cross-section at the crest expands excessively, resulting in a steep reverse pressure gradient. Both of these induce flow separation and local vortices, leading to a sharp increase in energy loss. Furthermore, the shedding of unsteady vortices in the separation zone will introduce additional unstable frequency components, interfering with the spectral order of the pre-modulated signal. An amplitude range of 10% to 20% ensures that the low-pressure zone formed at the crest is sufficient to enhance the intake of feedback fluid, and the high-pressure zone formed at the trough is sufficient to drive the propagation of pressure disturbance, while suppressing the separation risk within an acceptable range. This allows the local pressure modulation effect, the effective path extension effect, and the multi-reflection point effect to work in a coordinated manner. The coordinated operation of wave number and wave amplitude ensures that the sinusoidal waveform wall 5 can provide a pre-modulated feedback signal with rich spectrum and orderly structure for the subsequent hierarchical separation of the bifurcation partition 6.

[0043] In one embodiment, the wavelength of the sinusoidal waveform wall 5 is 8~12mm, and the effective length of the feedback channel 4 is 15~25mm.

[0044] The wavelength directly determines the spatial scale of a single expansion-contraction modulation cycle: when the wavelength is less than 8 mm, the spacing between adjacent peaks and troughs is too close, and the fluid needs to complete the full switching between cross-sectional expansion and cross-sectional contraction within a very short distance. The local pressure gradient is too large, and the boundary layer cannot follow the continuous change of the wall to separate, forming local vortex dissipation, which not only increases flow loss but also destroys the structural order of the modulation signal itself. When the wavelength is greater than 12 mm, the spatial distance spanned by a single modulation cycle is too long, and the sufficient number of cycles required to form a pulse sequence cannot be accommodated within the finite length of feedback channel 4. The multi-reflection point effect is significantly weakened, and the feedback signal is difficult to get rid of the single pulse characteristic, so the functional goal of distributed continuous modulation cannot be achieved. The effective length of feedback channel 4 is matched with the wavelength, creating a constraint: when the effective length is less than 15mm, even with a wavelength upper limit of 8mm, it is difficult to arrange fluctuations close to two complete cycles, and the modulation along the path cannot be fully developed due to insufficient space; when the effective length is greater than 25mm, the feedback signal propagates too far along the tortuous path of the sinusoidal waveform wall 5, and the pressure disturbance attenuates and accumulates along the path during multiple expansion-contraction processes. The feedback energy when it reaches the other side of the main cavity 2 is insufficient to effectively drive the jet switching. At the same time, the excessively long feedback delay loses timing match with the deflection switching cycle of the main jet in the main cavity 2, disrupting the stability of the oscillation rhythm. Therefore, an effective length of 15~25mm and a wavelength of 8~12mm work together to naturally accommodate 1.5~2 complete fluctuation cycles within feedback channel 4, allowing the distributed continuous modulation of the sinusoidal waveform wall 5 to be fully completed in the first and middle sections of feedback channel 4, while reserving space in the latter section for the modulated feedback flow to stably flow into the main cavity 2, thus achieving a synergistic satisfaction of modulation sufficiency, feedback strength, and oscillation timing match.

[0045] In one embodiment, the sinusoidal waveform wall 5 is disposed in the first two-thirds of the section at the inlet side of the feedback channel 4; The rear 1 / 3 section of the outlet side of feedback channel 4 is in the form of a straight wall or a slightly expanded form.

[0046] The inlet side of feedback channel 4 directly receives the feedback fluid diverted from the main cavity 2. At this time, the fluid has just left the high turbulence region of the main cavity 2, and the pressure disturbance itself carries large-scale unsteady fluctuation components generated when the main jet deflects and adheres to the wall. The original signal energy is sufficient, but the spectral structure is chaotic. By setting the sinusoidal waveform wall 5 in this front region, the window of high initial energy and strong adjustability of the fluid entering feedback channel 4 can be utilized to intervene in the initial stage of signal propagation with distributed continuous modulation—the alternation of peaks and troughs reshapes the spectrum of the original disturbance, transforming the large-scale disordered fluctuations into an ordered pulse sequence with multiple frequency components. This provides a clearly structured pre-modulated input for the subsequent hierarchical separation of the bifurcation partition 6. If the sinusoidal waveform wall 5 is placed in the latter part of the feedback channel 4, the fluid will first undergo a long straight wall section after entering the feedback channel 4. The original disturbance will naturally attenuate without modulation and the spectral structure will not be improved. When it reaches the latter part, the signal energy will be insufficient and the modulation window will have passed. The distributed modulation function of the sinusoidal waveform wall 5 will be greatly reduced due to the deterioration of the input signal quality. The latter 1 / 3 of the outlet side of the feedback channel 4 is restored to a straight wall or micro-expansion form. The functional goal complements the modulation section on the inlet side: the feedback pressure disturbance after being modulated by the first 2 / 3 of the sinusoidal waveform wall 5 has the required spectral richness and pulse sequence characteristics. If the sinusoidal waveform fluctuation is maintained at this time, the continuous cross-sectional change at the outlet end will introduce additional local disturbances at the critical surface where the feedback flow merges into the main cavity 2, interfering with the timing coupling accuracy between the modulated signal and the main jet. The use of a straight wall or micro-expansion form allows the feedback flow to complete the flow conditioning before merging into the main cavity 2, eliminating the secondary disturbances caused by the end cross-sectional change, and ensuring that the modulated signal merges into the other side of the main cavity 2 in a stable flow state, accurately participating in the jet switching drive. The micro-expansion involves a slight increase in the cross-section at the outlet end along the flow direction. This gradual expansion reduces flow velocity, stabilizes pressure, and further suppresses the risk of flow separation in the confluence zone. This segmented layout, with the first two-thirds modulation and the last one-third tidying, ensures that the distributed continuous modulation function along the sinusoidal waveform wall 5 and the stable inflow requirement of the feedback signal are both adequately addressed, achieving synergistic functional zoning between modulation sufficiency and outlet stability.

[0047] In one embodiment, the bifurcated partition 6 is arranged in the second peak to trough interval of the sinusoidal waveform wall 5, and the extension dimension of the bifurcated partition 6 in the width direction of the feedback channel 4 is 30% to 50% of the width of the feedback channel 4.

[0048] After the feedback fluid enters feedback channel 4, it undergoes its first expansion-contraction modulation cycle within the first wavelength range of the sinusoidal waveform wall 5. At this point, the fluid has just split from the main cavity 2, resulting in high velocity and turbulence. The original large-scale disturbance has not yet been fully modulated. If a bifurcation baffle 6 is installed here to split the flow, the initial difference between the two signals will be submerged by the original turbulence, and the time-scale separation effect between the main feedback channel 7 and the secondary feedback channel 8 will be unclear. After entering the second wavelength range, the fluid has completed at least one full cycle of modulation. The local pressure modulation effect of the sinusoidal waveform wall 5 has initially formed pulse sequence characteristics in the pressure disturbance. The multi-reflection point effect makes the signal spectrum structure more ordered. At the same time, the fluid velocity is moderately reduced due to the meandering path along the flow path. The pressure gradient is most significant in the transition range from the crest to the trough—the fluid, after the cross-section expands and the pressure increases at the crest, is entering the cross-section contraction section at the trough along the flow direction. The direction of the pressure gradient is consistent with the flow direction, and the driving pressure difference is clear. By setting a bifurcation baffle 6 in the section from the crest to the trough, the significant pressure gradient can be used to achieve natural flow splitting between the main feedback channel 7 and the secondary feedback channel 8: under pressure drive, most of the fluid passes quickly through the main feedback channel 7 with a large flow area, while a small portion of the fluid enters the secondary feedback channel 8 with a small flow area to form a delayed path. The ratio of the two flow splits is determined by the channel area ratio and the local pressure gradient, rather than by the randomness of the inlet turbulence. The flow splitting process has inherent determinism.

[0049] The extension dimension of the bifurcation baffle 6 in the width direction of the feedback channel 4 determines the flow area ratio and path length difference between the main feedback channel 7 and the secondary feedback channel 8. When the extension length is less than 30% of the width of the feedback channel 4, the bifurcation baffle 6 is insufficient to separate the sinusoidal waveform channel, the flow area of ​​the secondary feedback channel 8 is too small compared to the main feedback channel 7, the propagation time scales of the two channels are close, the dual-time-scale feedback mechanism degenerates into an approximate single-time-scale, and the functional goal of hierarchical feedback cannot be achieved. When the extension length is greater than 50% of the width of the feedback channel 4, the flow area of ​​the secondary feedback channel 8 is excessively compressed, the flow resistance in the channel increases significantly, the secondary feedback signal attenuates too much along the propagation process, and when it reaches the end of the bifurcation baffle 6, the energy is insufficient to form an effective coupling with the main feedback signal, and the secondary feedback channel 8 is rendered ineffective. At the same time, the excessively long bifurcation baffle 6 penetrates deep into the sinusoidal waveform channel, causing excessive blockage of the cross-sectional change flow field between the crest and trough, interfering with the path modulation function of the sinusoidal waveform wall 5. The 30% to 50% extension length range establishes a reasonable flow area ratio between the main feedback channel 7 and the secondary feedback channel 8. The secondary feedback channel 8 has sufficient flow space to maintain effective feedback flow and propagation energy. At the same time, its path length and flow resistance naturally form a discernible time difference with the main feedback channel 7. The dual time scale characteristics are clear, and the two signals have a couplerable energy matching relationship when they converge at the end of the partition.

[0050] The bifurcation baffle 6 is arranged in the second wave crest to trough interval in coordination with an extension length of 30% to 50%. The arrangement position utilizes the established ordered pressure gradient in the second wavelength interval to provide a deterministic shunting window, and the extension length ensures that the two channels after shunting meet the functional requirements of dual time-scale feedback in terms of time scale and energy ratio. Together, they enable the bifurcation baffle 6 to reliably re-separate the feedback signal based on the pre-modulation of the sinusoidal waveform wall surface 5, providing structural guarantee for the composite multi-scale feedback mechanism.

[0051] In one embodiment, the bifurcated partition 6 has a smooth transition design on the side near the entrance of the main cavity 2.

[0052] The inlet end of the bifurcation baffle 6 is located within the waveform range of the sinusoidal wall 5. The upstream fluid has already undergone path modulation by the sinusoidal wall 5, and its velocity and pressure distribution exhibit periodic characteristics corresponding to the waveform phase. The flow direction is not always parallel to the extension direction of the bifurcation baffle 6, but rather exhibits periodic oscillation at a certain angle with the alternation of wave crests and troughs. If the inlet end of the bifurcation baffle 6 adopts a sharp edge or a right angle, under the aforementioned periodic oscillating incoming flow conditions, flow separation will occur at the sharp edge, forming local separation bubbles on the inlet side of the bifurcation baffle 6. The separation bubbles periodically detach with the oscillation of the incoming flow, generating unsteady vortex shedding—these vortex sheddings are unrelated to the modulation signal of the sinusoidal wall 5 in frequency and phase, and belong to the introduced external interference, which will contaminate the modulated feedback pressure disturbance and destroy the spectral order of the pre-modulated signal. More importantly, the periodic shedding of the separation bubble causes the flow distribution ratio between the main feedback channel 7 and the secondary feedback channel 8 to fluctuate over time, the flow splitting ratio of the two channels loses its certainty, the time scale identification of the dual time scale feedback mechanism is reduced, and the re-separation function of the bifurcation baffle 6 is greatly reduced due to the uncertainty of the inlet flow.

[0053] The smooth transition design allows the inlet end of the bifurcation baffle 6 to smoothly transition from the wall to the baffle body with a continuous curvature. As the upstream fluid approaches the bifurcation baffle 6, the streamlines are smoothly divided into two streams along the smooth surface, entering the main feedback channel 7 and the secondary feedback channel 8 respectively, effectively suppressing flow separation. Under conditions of periodic oscillation in the incoming flow direction, the smooth surface's adaptability to different incident angles is far superior to that of a sharp edge. The flow attachment point can move continuously on the smooth surface without sudden separation, maintaining the continuity of the flow splitting process. Therefore, no additional unsteady disturbance source is introduced at the inlet end of the bifurcation baffle 6. The spectral structure of the feedback pressure disturbance pre-modulated by the sinusoidal wall surface 5 is completely preserved during the flow splitting process. The main feedback channel 7 and the secondary feedback channel 8 achieve a deterministic flow distribution ratio, and the separation effect on both time scales is clear. Simultaneously, the smooth transition avoids local pressure abrupt changes and concentrated energy dissipation at the sharp edge, playing a positive role in maintaining the feedback signal strength and controlling flow losses.

[0054] In one embodiment, the bifurcation angle of the bifurcation partition 6 is 15° to 30°.

[0055] The bifurcation angle refers to the deflection angle of the bifurcation baffle 6 relative to the length direction of the feedback channel 4. This angle directly determines the gradient of the flow area along the flow path between the main feedback channel 7 and the secondary feedback channel 8, as well as the smoothness of the flow split between the two fluid paths.

[0056] When the bifurcation angle is less than 15°, the bifurcation baffle 6 is nearly parallel to the length of the feedback channel 4. The flow area between the main feedback channel 7 and the secondary feedback channel 8 changes extremely slowly along the flow path, and the cross-sectional difference between the two channels is not significant throughout the entire length of the baffle, resulting in a weak flow-splitting driving force. Under these conditions, the fluid entering the feedback channel 4 is insensitive to the presence of the bifurcation baffle 6, and most of the fluid passes directly along the inertial direction. The secondary feedback channel 8 cannot obtain sufficient flow distribution, and its flow basis as a delayed feedback path is not valid. The dual-timescale feedback mechanism degenerates into an approximately single-path propagation dominated by the main feedback channel 7, and the functional objective of hierarchical feedback is not achieved. Furthermore, the excessively small bifurcation angle makes the gap between the end of the bifurcation baffle 6 and the opposite sinusoidal wall 5 change too gently along the flow path. The convergence of the two signals at the end of the baffle lacks a clear pressure gradient driving force, resulting in a weak coupling interference effect.

[0057] When the bifurcation angle is greater than 30°, the bifurcation baffle 6 deviates significantly from the length direction of the feedback channel 4. The cross-section of the main feedback channel 7 narrows rapidly along its length, while the cross-section of the secondary feedback channel 8 expands rapidly, resulting in a steep gradient in the flow area. This steep area change creates a strong lateral pressure gradient at the inlet end of the bifurcation baffle 6, driving the fluid to deflect towards the secondary feedback channel 8. However, an excessively strong lateral pressure gradient leads to an overly drastic flow splitting process—the fluid suddenly changes direction upon entering the bifurcation region, causing local flow separation on the baffle's upstream surface and forming a separation vortex independent of the sinusoidal waveform wall surface 5 modulation signal. This separation vortex not only increases local energy dissipation but, more importantly, introduces additional unsteady disturbance frequencies, causing spectral pollution to the modulated feedback pressure disturbance. Simultaneously, the excessively large bifurcation angle causes a drastic change in the connection gap between the end of the bifurcation baffle 6 and the opposite wall surface, resulting in a strong shear layer when the two signals converge. The coupling process is accompanied by additional energy loss and signal distortion.

[0058] The bifurcation angle range of 15° to 30° allows the bifurcation baffle 6 to establish a flow area difference between the main feedback channel 7 and the secondary feedback channel 8 with a moderate deflection gradient: the angle is sufficient to form a clear shunting driving force, ensuring that the secondary feedback channel 8 obtains stable flow distribution to maintain effective delayed feedback function; at the same time, the area change gradient is controlled within a range where the flow can be smoothly followed, avoiding flow separation and additional disturbances in the shunting zone, and ensuring that the spectral structure of the feedback signal premodulated by the sinusoidal waveform wall 5 is completely preserved during the shunting process. Within this angle range, a reasonable connection gap change is formed between the end of the bifurcation baffle 6 and the opposite sinusoidal waveform wall 5, and the main feedback signal and the secondary feedback signal complete coupling interference with controllable shear strength in the merging region, ensuring the timing coordination quality of the dual time-scale feedback signals.

[0059] In one embodiment, the amplitude of the sinusoidal waveform wall 5 gradually changes along the length of the feedback channel 4: the amplitude of the sinusoidal waveform wall 5 at the inlet side of the feedback channel 4 is a first value, the amplitude at the middle section is a second value, and the amplitude at the outlet side is a third value, with the first value > the second value > the third value, and the third value approaching zero.

[0060] The feedback fluid at the inlet side of feedback channel 4 originates from the main cavity 2. At this point, the original energy of the pressure disturbance is the highest, and the signal tunability is the strongest. However, the spectral structure of the unmodulated original signal is chaotic, with large-scale disturbance components dominating. By setting a large initial amplitude at the inlet side, the peak cross-section is fully expanded, and the trough cross-section is fully contracted, forming the strongest local pressure gradient. High-intensity distributed continuous modulation is used to deeply reshape the spectrum of the original high-energy signal, effectively transforming the large-scale disordered disturbance into an ordered pulse sequence with multiple frequency components. This fully utilizes the initial high-energy window to complete the main modulation work.

[0061] The mid-range amplitude is set to a second value, less than the first value. At this point, the fluid has undergone initial shaping through high-intensity modulation at the inlet side, and large-scale components in the signal have been effectively suppressed, resulting in a more ordered spectral structure. However, there is still room for optimization in the energy ratio between the components of the pulse sequence. If the high amplitude at the inlet side is maintained in the mid-range, excessive modulation will over-interfere with the initially shaped signal, introducing unnecessary additional frequency components and thus disrupting the orderliness of the signal structure. If modulation is completely canceled in the mid-range, the initially established pulse sequence characteristics have not yet been consolidated, and the signal may gradually lose spectral richness due to attenuation along the propagation path. Maintaining a moderate modulation rhythm in the mid-range with a second value of moderate amplitude provides consolidating modulation to the initially shaped signal, ensuring the stable continuation of the pulse sequence characteristics while avoiding energy loss and signal distortion caused by over-modulation.

[0062] The amplitude on the outlet side is set to a third value approaching zero, meaning the sinusoidal waveform wall 5 gradually transitions to a straight wall or slightly expanded form at the outlet end. At this point, the feedback pressure disturbance has been fully pre-modulated in the front and middle sections, and the signal possesses the required spectral richness and pulse sequence structure, achieving the functional objective. If the outlet end continues to maintain an undulating waveform, the continuous cross-sectional change will introduce end disturbances in the critical region where the feedback flow merges into the main cavity 2, interfering with the precise coordination between the modulated signal and the main jet deflection switching timing. The amplitude gradually approaches zero, causing the outlet end wall to smoothly transition to a straight wall or slightly expanded form with continuous curvature, forming a gentle spatial connection between the modulation section and the merging section. The modulated feedback signal undergoes flow conditioning at the end to stabilize the flow state before merging into the other side of the main cavity 2, ensuring that the pre-modulation results are not disrupted in the final merging stage. This gradient design, along with the sine wave wall 5 set in the first 2 / 3 and the last 1 / 3 of the feedback channel 4 in the form of straight walls or slightly expanded sections, can be implemented in synergy. This allows the amplitude to decrease along the path and the transition from the modulation section to the settling section to naturally overlap in space, thus achieving a smooth switching between modulation intensity and output stability along the path.

[0063] In one embodiment, the feedback channel 4 is provided with multiple bifurcated partitions 6 to divide the inside of the sine waveform channel into two or more levels of multi-level feedback channels, forming a multi-timescale feedback mechanism.

[0064] A single bifurcated partition 6 divides the sinusoidal waveform channel into two levels: a primary feedback channel 7 and a secondary feedback channel 8, forming feedback paths with two macroscopic time scales: fast and slow. The coverage of these time scales is determined by the ratio of the flow area of ​​the two channels and the difference in their path lengths. When the operating conditions of the application scenario are extremely wide—for example, a nozzle needs to adapt to both extremely low pressure start-up and ultra-high pressure stable operation—the discrete separation of the two time scales may not be sufficient to cover all timing requirements from fast response to long-delay feedback, resulting in gaps in intermediate time scales and limiting the richness of the temporal structure of the feedback signal.

[0065] Multiple bifurcated baffles 6 are added within the feedback channel 4, for example, two parallel bifurcated baffles, which can divide the sinusoidal waveform channel into three levels: the main feedback channel, the first-stage feedback channel, and the second-stage feedback channel, forming a feedback mechanism with three macroscopic time scales: fast, medium, and slow. The flow area of ​​each level of the channel decreases sequentially, the propagation path increases sequentially, and the feedback delay increases sequentially. Multiple signals converge at the end of the baffles, forming a composite feedback pulse structure with three time peaks. Compared to dual time scales, the pressure drive generated by the three-time-scale feedback signal in the main cavity 2 has a wider timing coverage and can automatically match the most suitable feedback delay under different operating pressures: during low-pressure startup, the fast signal of the main feedback channel provides timely switching drive, while the medium and slow signals provide continuous pressure accumulation support, reducing the oscillation threshold; during high-pressure operation, the long-delay signal of the slow feedback channel effectively suppresses the oscillation rhythm disorder caused by the rapid switching of the main jet, and the medium-speed signal fills the timing transition between fast and slow, keeping the oscillation period stable across the entire operating range.

[0066] In one embodiment, the bifurcated partition 6 extends inward from the outer sinusoidal waveform wall of the feedback channel 4 by 3-5 mm, and is 1-2 mm away from the inner sinusoidal waveform wall. In this case, the channel on the outer side of the bifurcated partition 6 is the main feedback channel 7, and the one closer to the main cavity 2 is the secondary feedback channel.

[0067] The extension dimension of 3-5mm determines the separation depth of the bifurcation baffle 6 on the sinusoidal waveform channel: when the extension dimension is less than 3mm, the separation effect of the bifurcation baffle 6 is too weak, the difference in flow area between the main feedback channel 7 and the secondary feedback channel 8 is insufficient, the propagation time scales of the two channels are close, the dual time scale feedback mechanism degenerates into an approximate single-path propagation, and the functional goal of hierarchical feedback cannot be achieved; when the extension dimension is greater than 5mm, the bifurcation baffle 6 penetrates too deeply into the sinusoidal waveform channel, the flow area of ​​the main feedback channel 7 is excessively compressed, the flow resistance in the channel increases significantly, the attenuation of the main feedback signal along the propagation process is aggravated, the feedback energy when it reaches the other side of the main cavity 2 is insufficient, and it cannot effectively drive the jet switching. At the same time, the excessively deep baffle causes excessive blockage of the cross-sectional change flow field between the peak and trough of the sinusoidal waveform wall 5, interfering with the normal operation of the distributed continuous modulation along the path.

[0068] A 1-2mm gap is maintained between the end of the bifurcated baffle 6 and the inner sinusoidal wall surface. This gap is crucial for fluid communication and signal coupling between the main feedback channel 7 and the secondary feedback channel 8. When the gap is less than 1mm, the connection is too narrow, and the fluid in the main feedback channel 7 is strongly compressed at the end of the baffle, resulting in a sharp increase in local velocity and a sudden drop in pressure, leading to additional pressure loss and the risk of flow separation. At the same time, the fluid in the secondary feedback channel 8 cannot effectively merge with the main feedback signal through the narrow gap, resulting in insufficient coupling interference between the two signals and weakening the synergistic effect of the composite feedback. When the gap is greater than 2mm, the connection is too wide, and the separation effect between the main feedback channel 7 and the secondary feedback channel 8 at the end of the baffle is significantly diluted. The time difference established between the two channels within the extension length of the baffle is prematurely smoothed out in the merging area, reducing the discernibility of the dual time scales and making the separation effect of the hierarchical feedback unclear.

[0069] The present invention also provides a method for fluid oscillation control using the above-mentioned oscillating nozzle with composite feedback channel control, comprising the following steps: After the main jet enters the main cavity 2 through inlet section 1, a portion of the fluid enters the feedback channel 4; this step is the initiation of the feedback loop. After entering the main cavity 2 from inlet section 1, the main jet expands under the geometric constraints of the cavity, increasing its cross-section and decreasing its velocity, forming a large-scale flow structure with a transverse pressure gradient within the main cavity 2. When the main jet deflects and adheres to a wall on one side within the main cavity 2, the pressure on that side increases. The inlet end of the feedback channel 4 on that side is in a high-pressure region, while the inlet end of the opposite feedback channel 4 is in a low-pressure region. This pressure difference drives a portion of the fluid from the high-pressure side into the inlet end of the feedback channel 4 on the same side, initiating the feedback loop. The fluid entering the feedback channel 4 carries the original pressure disturbance information generated by the main jet deflecting and adhering to the wall; its signal strength is directly related to the wall state within the main cavity 2. This diversion process is passive, requiring no external drive, and can be maintained solely by the transverse pressure difference naturally established by the main jet deflecting and adhering to the wall.

[0070] The fluid, within the sinusoidal channel formed by the sinusoidal wave wall 5, alternately experiences cross-sectional expansion at crests and contraction at troughs, undergoing distributed continuous pressure modulation to form a feedback pressure disturbance containing multiple frequency components. This step is the pre-modulation stage of the feedback signal, achieved through the continuous undulation structure of the sinusoidal wave wall 5. As the fluid enters the feedback channel 4 and propagates along the sinusoidal wave wall 5, the channel cross-section expands at the crests, causing a decrease in fluid velocity and an increase in pressure, forming a local high-pressure zone; at the troughs, the channel cross-section contracts, increasing fluid velocity and decreasing pressure, forming a local low-pressure zone. The alternating arrangement of crests and troughs causes the fluid to repeatedly experience expansion-contraction cycles during propagation, with each cycle locally modulating the pressure disturbance. A single crest-trough combination constitutes a modulation unit, and multiple modulation units act sequentially along the path, gradually shaping the original pressure disturbance into a pulse sequence with multiple frequency components. Meanwhile, the tortuous path of the sinusoidal wall 5 causes the actual propagation distance of the fluid to be greater than the straight-line distance, naturally increasing the feedback delay without increasing the external dimensions of the feedback channel 4. The cross-sectional changes at each peak and trough constitute local reflection points, and the pressure wave undergoes partial reflection and transmission between multiple reflection points, causing the feedback signal to unfold into a multi-peak pulse structure in time, avoiding the overshoot or undershoot that may occur with a single pulse in a traditional straight-wall channel. After this step, the spectral richness and structural order of the feedback pressure disturbance are improved, providing a pre-modulated input for subsequent graded separation.

[0071] The feedback pressure disturbance, separated by the bifurcated partition 6, enters the main feedback channel 7 and the secondary feedback channel 8 respectively, forming a fast main feedback signal and a delayed secondary feedback signal with different propagation times. This step is a hierarchical separation stage of the feedback signal, achieved by the channel separation structure of the bifurcated partition 6. When the feedback pressure disturbance, pre-modulated by the sinusoidal waveform wall 5, reaches the inlet end of the bifurcated partition 6, under the separation effect of the bifurcated partition 6, most of the fluid passes quickly along the main feedback channel 7 with a large flow area, while a small portion of the fluid enters the secondary feedback channel 8 with a small flow area. The main feedback channel 7 has a large flow area and low frictional resistance, allowing the fluid to propagate at a higher speed and in a shorter time, forming a fast main feedback signal. The secondary feedback channel 8 has a small flow area, high frictional resistance, and a tortuous path, allowing the fluid to propagate at a lower speed and in a longer time, forming a delayed secondary feedback signal. The two signals remain separated within the extended length of the bifurcated partition 6, propagating independently, and undergo coupling interference in the confluence area at the end of the partition. The dual-timescale separation process is deterministic: the flow area ratio of the two channels is predetermined by the extension length and bifurcation angle of the bifurcation baffle 6; the flow distribution ratio and propagation time difference are repeatable and not dominated by the randomness of the upstream flow. The functional connection between pre-modulation and re-separation ensures that the distributed continuous modulation results of the sinusoidal waveform wall 5 are completely preserved during the flow separation process; the bifurcation baffle 6 does not introduce additional unsteady disturbances; and the time difference between the main feedback signal and the secondary feedback signal is clear and the energy ratio is reasonable.

[0072] The primary and secondary feedback signals return to the other side of the main cavity 2 via the feedback channel 4, acting synergistically on the main jet with composite multi-timescale feedback pressure. This drives the main jet to periodically deflect and switch within the main cavity 2, ultimately ejecting from the outlet section 3 to form a periodically oscillating jet. This step is the synergistic driving link of the composite feedback signals, realizing the closure of the feedback loop. The rapid primary feedback signal arrives first at the other side of the main cavity 2, creating an initial pressure increase there. This applies an initial deflection driving force to the main jet already attached to the opposite wall, initiating the jet switching process. The delayed secondary feedback signal arrives subsequently, superimposing an auxiliary pressure increment on the initial pressure established by the primary feedback signal, enhancing the continuity of the deflection drive. The time difference between the two signals ensures that the pressure rise on the other side of the main cavity 2 is not a step-like abrupt increase, but rather a gradual increase with a rising front and a sustained plateau: the primary feedback signal provides the rapidly rising front, while the secondary feedback signal provides the continuation and reinforcement of the pressure plateau. This composite pressure-driven characteristic enables the main jet to obtain a continuous deflection torque during the switching process, rather than a single-impact deflection. The switching process is smooth and thorough, avoiding incomplete switching due to insufficient driving force or overshooting oscillation due to overshooting driving force. The micro-timescale modulation of the sinusoidal waveform wall 5 makes the pulse sequence carried by the feedback signal appear as a high-frequency fine-tuning component in the pressure drive, smoothing the local pressure fluctuations during the main jet switching process; the macro-timescale separation of the bifurcation baffle 6 provides a continuous driving force with wide temporal coverage for the main jet switching. Under the synergistic effect of the two, the main jet forms a periodically stable and highly repeatable left-right deflection switching in the main cavity 2, and finally ejects from the outlet section 3 to form a periodically oscillating jet with a wide coverage and strong mixing ability.

[0073] The above description is merely an embodiment and does not constitute any limitation on the present invention. Any person skilled in the art can make many possible variations, modifications, or alterations to the technical solutions of the present invention without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.

Claims

1. An oscillating nozzle with composite feedback channel control, characterized in that, It includes an inlet section (1), a main cavity (2), an outlet section (3), and feedback channels (4) symmetrically arranged on both sides of the main cavity (2), with the two ends of the feedback channels (4) respectively connected to the main cavity (2); The channel wall of the feedback channel (4) is a sinusoidal waveform wall (5), which undulates periodically along the length of the feedback channel (4) to form a sinusoidal waveform channel for distributed continuous modulation of the feedback pressure disturbance along the path. The feedback channel (4) is also provided with a bifurcated partition (6), which extends along the length of the feedback channel (4) and divides the inside of the sine wave channel into a main feedback channel (7) with a large flow area and a secondary feedback channel (8) with a small flow area. The main feedback channel (7) and the secondary feedback channel (8) have different feedback pressure propagation time scales.

2. The oscillating nozzle with composite feedback channel control according to claim 1, characterized in that, The sinusoidal waveform wall (5) has an undulation period of 1.5 to 2 complete wavelengths along the length of the feedback channel (4), and the amplitude is 10% to 20% of the width of the feedback channel (4).

3. The oscillating nozzle with composite feedback channel control according to claim 2, characterized in that, The wavelength of the sinusoidal waveform wall (5) is 8~12mm, and the effective length of the feedback channel (4) is 15~25mm.

4. The oscillating nozzle with composite feedback channel control according to claim 1, characterized in that, The sinusoidal waveform wall (5) is located in the first 2 / 3 of the input side of the feedback channel (4); The last 1 / 3 of the outlet side of the feedback channel (4) is a straight wall or a slightly expanded form.

5. The oscillating nozzle with composite feedback channel control according to claim 1, characterized in that, The bifurcation partition (6) is arranged in the second peak to trough interval of the sinusoidal waveform wall (5), and the extension dimension of the bifurcation partition (6) in the width direction of the feedback channel (4) is 30% to 50% of the width of the feedback channel (4).

6. The oscillating nozzle with composite feedback channel control according to claim 5, characterized in that, The bifurcated partition (6) has a smooth transition design on the inlet side near the main cavity (2).

7. The oscillating nozzle with composite feedback channel control according to claim 5, characterized in that, The bifurcation angle of the bifurcation partition (6) is 15°~30°.

8. The oscillating nozzle with composite feedback channel control according to claim 1, characterized in that, The amplitude of the sinusoidal waveform wall (5) gradually changes along the length of the feedback channel (4): the amplitude of the sinusoidal waveform wall (5) at the entrance of the feedback channel (4) is the first value, the amplitude at the middle section is the second value, and the amplitude at the exit is the third value. The first value > the second value > the third value, and the third value approaches zero.

9. The oscillating nozzle with composite feedback channel control according to claim 1, characterized in that, The feedback channel (4) is provided with multiple bifurcated partitions (6) to divide the inside of the sine waveform channel into two or more levels of multi-level feedback channels, forming a multi-time scale feedback mechanism.

10. A method for controlling fluid oscillation, employing an oscillating nozzle with composite feedback channel control as described in any one of claims 1-9, characterized in that, The process includes the following: After the main jet enters the main cavity (2) through the inlet section (1), a portion of the fluid enters the feedback channel (4). The fluid, within the sinusoidal channel formed by the sinusoidal wall (5), alternately experiences cross-sectional expansion at the crest and cross-sectional contraction at the trough, and is subjected to distributed continuous pressure modulation, forming a feedback pressure disturbance containing multiple frequency components. The feedback pressure disturbance, under the separation effect of the bifurcated partition (6), enters the main feedback channel (7) and the secondary feedback channel (8) respectively, forming a fast main feedback signal and a delayed secondary feedback signal with different propagation times; The main feedback signal and the secondary feedback signal return to the other side of the main cavity (2) through the feedback channel (4), and the combined multi-timescale feedback pressure acts on the main jet, driving the main jet to deflect and switch periodically in the main cavity (2), and finally ejected from the outlet section (3) to form a periodic oscillating jet.

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