CN114822464A - Cavity noise suppression method adopting bulge type protrusions - Google Patents
Cavity noise suppression method adopting bulge type protrusions Download PDFInfo
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- CN114822464A CN114822464A CN202210462081.1A CN202210462081A CN114822464A CN 114822464 A CN114822464 A CN 114822464A CN 202210462081 A CN202210462081 A CN 202210462081A CN 114822464 A CN114822464 A CN 114822464A
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/161—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general in systems with fluid flow
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/10—Drag reduction
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Abstract
The invention discloses a cavity noise suppression method adopting bulge type protrusions, which is characterized in that a flow shear layer at the front edge of a cavity is physically lifted in the direction of the incoming flow on a cavity structure; the bulge type bulges are used for lifting the flowing shear layer, so that the cavity noise is effectively reduced; by using the bulge type protrusion, the appearance is smooth and continuous, and the influence on the pneumatic characteristic is reduced; by using the bulge, the appearance is simple, and the conversion from a passive control mode to an active control mode can be directly realized by combining the flexible skin technology and the deformation mechanism.
Description
Technical Field
The invention relates to the field of cavity noise control in computational fluid dynamics, in particular to a noise suppression method and a noise suppression structure of a cavity structure.
Background
The cavity structure is widely applied to the fields of buildings, aerospace, automobiles and the like. Flow through the cavity can produce resonance noise, numerous flow/acoustic instabilities, and complex wave interactions. In order to suppress the noise problem caused by the cavity structure, the common solutions at present are: and a spoiler, a vortex generator, a sub-cavity and other passive modes are arranged at the upstream, or an oscillating plate, piezoelectric equipment, mass jet, a resonance tube and other active modes are utilized. These methods can suppress the cavity noise to some extent, but all have respective disadvantages:
the prior passive control method is usually installed at the upstream of the cavity front edge or directly changes the wall surface inclination angle of the downstream cavity. The control modes installed at the upstream only consider noise suppression, but do not consider the reduction of aerodynamic characteristics caused by obvious change of a flow field; the downstream cavity wall change shape limits the scope of use of cavity structures such as that disclosed in patent publication CN 111470028A.
The existing active control mode, or the difficulty of engineering implementation is large, or the control effect is only better in a specific condition, and a good active control mode actually approved by engineering is not available at present, such as the open patent CN 111564149A.
Disclosure of Invention
The invention aims to design a noise suppression method, wherein a bulge type bulge is adopted to lift a flow shear layer, so that cavity noise is effectively reduced.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for suppressing the noise of cavity by using bulge features that the flow shear layer at front edge of cavity is physically raised up by the cavity structure toward the incoming flow direction.
In the above solution, the physical elevation is a raised structure provided upstream of the leading edge.
In the above technical solution, the protrusion structure is a bulge type protrusion.
In the above technical solution, the surface of the convex structure is smoothly continuous with the upstream plane.
In the technical scheme, the protruding structure is located at a certain distance upstream of the front edge of the cavity, and the value of the protruding structure is about 5-7 times of the height of the incoming flow boundary layer.
In the above technical solution, the shape change of the protruding structure at least needs to reach second order continuity.
In the technical scheme, the physical lifting height is determined according to the incoming flow velocity boundary layer, and the height of the physical lifting height is 0.5-1.0 of the height of the boundary layer.
In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:
the invention adopts the bulge type bulge and has good noise reduction effect. The front-mounted bulge can effectively raise the flowing shear layer, so that a feedback loop of cavity noise can be effectively influenced, and a good noise reduction effect can be achieved;
the invention adopts the bulge type bulge, and can effectively reduce the influence on the pneumatic characteristic. The bulge type protrusion can be in smooth and continuous transition with the upstream surface of the cavity structure, and the sharp decrease of the pneumatic characteristic caused by discontinuous transition in the traditional mode can be reduced;
the invention adopts the bulge type bulge, can flexibly realize the conversion from a passive control mode to an active mode, and expands the limitation of use conditions. The bulge type bulge can be changed from passive control to active control by combining the flexible skin technology and the deformation mechanism. Therefore, the application range of the device can be expanded, and the defect that the traditional active mode and the passive mode cannot be effectively combined is overcome.
Drawings
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a schematic cross-sectional view of a bulge-type bump cavity noise suppression approach;
FIG. 2 is a schematic diagram of a two-dimensional bulge geometry profile parameter;
FIG. 3 is a schematic view of a cavity leading edge mounting bump;
FIG. 4 is a schematic view of a cavity leading edge mounting bump;
wherein: 1 is a raised structure, 2 is a leading edge, and 3 is a trailing edge.
Detailed Description
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
As shown in fig. 1, it is a schematic structural diagram of the present embodiment, wherein the cavity structure includes a cavity with an opening on one side, a leading edge 2 and a trailing edge 3, and in actual operation, cavity noise is caused by coupling vortex shedding in a shear layer of the leading edge of the cavity with a fronthaul pressure disturbance generated by the impact of the vortex shedding on the trailing edge of the cavity.
The mode that this embodiment adopted is along the air incoming flow direction at the upstream of leading edge 2 setting bulging structure 1 of package formula to raise the shear layer of flow, avoid the vortex to drop and carry out the striking with the trailing edge, thereby play good reduction cavity noise's effect.
In the embodiment, the bulge type protrusion is located at a certain distance (the value is about 5-7 times of the height of the incoming flow boundary layer) upstream of the front edge of the cavity, and the shape of the bulge type protrusion structure 1 needs to be defined, so that the influence of the bulge type protrusion structure 1 on the aerodynamic characteristics is reduced. The convex structure 1 therefore adopts a smooth continuity in profile with the upstream surface, overcoming the drawback of the drastic drop in aerodynamic characteristics due to the discontinuity in profile of the remaining inhibiting measures.
In this embodiment, the change in the shape of the bulge is at least geometrically continuous (i.e., the curvature changes continuously) of the second order.
In the embodiment, the height of the bulge is determined according to the incident flow velocity boundary layer, and the height of the bulge is 0.5-1.5 of the height of the boundary layer.
Specific examples
1) Designing a cavity structure with one cavityxWhen the length of the steel wire is 1.8288 m,ytowards the inside of the test bed with a width of 0.4318m, the front edge of the cavity is 0.7874 m away from the front edge of the test bed. The length of the cavity isL=0.508 m and a depth ofD=0.1016 m, width ofW=0.1016 m. At an incoming flow Mach number ofMaAt a flow of =0.85, the cavity generates strong cavity noise.
2) For such cases, the boundary layer height created at the leading edge of the cavity can be found to be about 10 mm by simple simulation calculations (directly simulating the flow of the slab under the current flow, resulting in a boundary layer height 0.7874 m from the leading edge of the slab).
3) The bulge design is based on the boundary layer height of the cavity leading edge. For a general two-dimensional bulge, as shown in fig. 2, the main parameters of the bulge include: height, length, asymmetry. In the drawingsl B In order to be the length of the bulge,h B in order to be the height of the bulge,x 0 in order to be the starting position of the bulge,x B at any point on the bulge curvexThe coordinates of the position of the object to be imaged,x C being the apex of a bulgexCoordinates, definition x = (x =: (x))x B -x 0 )/l B Indicating the relative position of any point on the drum within the drum,x∈[0,1]。
4) the height is selected to be 0.5-1.5 times of the height of the boundary layer, and the height is selected to be 10 mm; the length is selected to be 1.0-5.0 times of the height of the bulge, and the length is selected to be 30 mm; the asymmetry is in the range of 0.3-0.7, where 0.5 is selected (i.e. the symmetric bulge). In three-dimensional flow, there are also variations in the spanwise length of the bump and the height of the bump in the spanwise direction, where the spanwise length of the bump is chosen to be greater than the width of the cavity, 1.2 times the width of the bump, i.e. 121.92 mm wide, and smooth transitions are made. Thus, a schematic view of the designed bulge mounted at the leading edge of the cavity is shown in FIG. 3.
5) Through numerical simulation, the method can effectively reduce the flow noise at the bottom of the cavity. Fig. 4 shows a plot of the total sound pressure level at the bottom of the cavity with/without the leading edge bulge approach, which shows that the total sound pressure level decreases by about 3 dB with the addition of the bulge approach.
The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.
Claims (7)
1. A method for suppressing cavity noise by adopting bulge type protrusions is characterized by comprising the following steps: the flow shear layer at the leading edge of the cavity is physically lifted up against the incoming flow direction on the cavity structure.
2. The method for suppressing cavity noise using a bulge according to claim 1, wherein: the physical elevation is a raised structure disposed upstream of the leading edge.
3. The method for suppressing cavity noise using a bulge according to claim 2, wherein: the protruding structure is a bulge type protrusion.
4. A method of suppressing cavity noise using a bulge according to claim 2 or 3, wherein: the surface of the convex structure is smoothly continuous with the upstream plane.
5. A method of suppressing cavity noise using a bulge according to claim 2 or 3, wherein: the protruding structure is located a distance of cavity leading edge upper reaches, and its value is 5 ~ 7 times incoming flow boundary layer height.
6. A method of suppressing cavity noise using a bulge according to claim 2 or 3, wherein: the shape change of the convex structure at least reaches second-order continuity.
7. The method for suppressing cavity noise using a bulge according to claim 1, wherein: the physical raised height is determined according to the incoming flow velocity boundary layer, and the height of the physical raised height is 0.5-1.5 of the height of the boundary layer.
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Citations (9)
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|---|---|---|---|---|
| DE3709080A1 (en) * | 1987-03-19 | 1988-12-15 | Pelzer Helmut | Multilayer cover element for oscillating surfaces |
| WO2002085648A1 (en) * | 2001-04-19 | 2002-10-31 | Societe De Technologie Michelin | Device for attenuating cavity noise in a tire and wheel |
| CN105082876A (en) * | 2015-09-28 | 2015-11-25 | 清华大学 | Wheel and vehicle provided with same |
| CN105745095A (en) * | 2013-10-24 | 2016-07-06 | 宾利汽车有限公司 | Tyre cavity noise absorber |
| CN110296039A (en) * | 2019-07-24 | 2019-10-01 | 广东工业大学 | A kind of wind electricity blade and the wind-driven generator with the wind electricity blade |
| CN111120461A (en) * | 2020-01-19 | 2020-05-08 | 中国人民解放军海军工程大学 | Underwater flow excitation cavity noise control device |
| CN211543156U (en) * | 2019-11-29 | 2020-09-22 | 特拓(青岛)轮胎技术有限公司 | Combined type tire cavity noise reduction device and tire equipped with same |
| CN111780242A (en) * | 2020-06-08 | 2020-10-16 | 珠海格力电器股份有限公司 | Indoor unit of air conditioner with upper air outlet and lower air outlet, control method and air conditioner |
| CN111874029A (en) * | 2020-07-28 | 2020-11-03 | 中车长春轨道客车股份有限公司 | High-speed train pilot structure capable of reducing pneumatic noise |
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Patent Citations (9)
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|---|---|---|---|---|
| DE3709080A1 (en) * | 1987-03-19 | 1988-12-15 | Pelzer Helmut | Multilayer cover element for oscillating surfaces |
| WO2002085648A1 (en) * | 2001-04-19 | 2002-10-31 | Societe De Technologie Michelin | Device for attenuating cavity noise in a tire and wheel |
| CN105745095A (en) * | 2013-10-24 | 2016-07-06 | 宾利汽车有限公司 | Tyre cavity noise absorber |
| CN105082876A (en) * | 2015-09-28 | 2015-11-25 | 清华大学 | Wheel and vehicle provided with same |
| CN110296039A (en) * | 2019-07-24 | 2019-10-01 | 广东工业大学 | A kind of wind electricity blade and the wind-driven generator with the wind electricity blade |
| CN211543156U (en) * | 2019-11-29 | 2020-09-22 | 特拓(青岛)轮胎技术有限公司 | Combined type tire cavity noise reduction device and tire equipped with same |
| CN111120461A (en) * | 2020-01-19 | 2020-05-08 | 中国人民解放军海军工程大学 | Underwater flow excitation cavity noise control device |
| CN111780242A (en) * | 2020-06-08 | 2020-10-16 | 珠海格力电器股份有限公司 | Indoor unit of air conditioner with upper air outlet and lower air outlet, control method and air conditioner |
| CN111874029A (en) * | 2020-07-28 | 2020-11-03 | 中车长春轨道客车股份有限公司 | High-speed train pilot structure capable of reducing pneumatic noise |
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