CN113092056A - Method for measuring three-dimensional density field of hypersonic flow field - Google Patents
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Abstract
A method for measuring a three-dimensional density field of a hypersonic flow field relates to the field of pneumatic research of the hypersonic flow field and comprises the following steps: s1: in the wind-cut state, a flow field is subjected to image acquisition by using a measuring device to obtain a static background spot image; s2: under the blowing state, the flow field is subjected to image acquisition by using the measuring device again to obtain a dynamic background spot image; s3: solving displacement vectors of the speckles in the static background speckle image and the dynamic background speckle image by adopting a particle image cross-correlation algorithm; s4: calculating the projection result of the distribution of the quantitative refractive index field and the density field in each direction according to the Fermat principle and the Grasston-Del law; s5: and reconstructing the three-dimensional density field distribution of the flow field to be measured by adopting a filtering back projection algorithm according to the projection result. The flow field display and measurement capability of the complicated flow of the flow field is improved by comprehensively using the pulse laser illumination, the multi-direction flow field projection data acquisition and the back projection filtering reconstruction technology.
Description
Technical Field
The invention relates to the field of pneumatic research of a hypersonic flow field, in particular to a method for measuring a three-dimensional density field of the hypersonic flow field.
Background
The hypersonic velocity flow field measurement technology has important significance for deeply researching the flow-around flow field mechanism of various aircrafts. At present, the technologies for measuring the density of the flow field mainly comprise a schlieren technology, an interference technology, a shadow technology and the like, the flow field is mostly used for qualitative display of the flow field, a measuring area is limited by the size of an optical lens, the light path adjustment is complex, and the measurement is interfered by ambient light or self-luminescence of the flow field.
In view of this, the present application is specifically made.
Disclosure of Invention
The invention aims to provide a hypersonic flow field three-dimensional density field measuring method, which improves the flow field display and measurement capability of complicated flow of a hypersonic flow field and meets the increasing requirement of large-size refined flow field test by comprehensively using pulse laser illumination, multi-direction flow field projection data acquisition and back projection filtering reconstruction technology.
The embodiment of the invention is realized by the following steps:
a method for measuring a three-dimensional density field of a hypersonic flow field comprises the following steps:
s1: in the wind-cut state, a flow field is subjected to image acquisition by using a measuring device to obtain a static background spot image;
s2: under the blowing state, the flow field is subjected to image acquisition by using the measuring device again to obtain a dynamic background spot image;
s3: solving displacement vectors of speckles in the static background speckle image and the dynamic background speckle image in the same direction by adopting a particle image cross-correlation algorithm;
s4: according to the Fermat principle and the Grasston-Diel law, the projection result of the distribution of the quantitative refractive index field and the density field in each direction of the flow field to be measured can be obtained through calculation;
s5: and reconstructing the three-dimensional density field distribution of the flow field to be measured by adopting a filtering back projection algorithm according to the projection result.
Furthermore, the measuring device comprises a pulse laser light source, a light guide member and a camera, wherein the light guide member and the camera are correspondingly arranged on two sides of the flow field, and light rays transmitted by the light guide member coincide with the optical axis of the camera.
Furthermore, the plurality of light guide members and the plurality of cameras are distributed along the circumferential direction of the flow field correspondingly, a plurality of wide light rays emitted by the pulse laser light source correspondingly penetrate through the plurality of light guide members and then enter the flow field, and a plurality of cameras correspondingly shoot background spot images so as to obtain a plurality of static background spot images and dynamic background spot images.
Further, the light guide component comprises a beam expanding and light homogenizing assembly and a background plate, the optical axis of the camera is perpendicular to the background plate, the background plate is provided with randomly distributed spots, the imaging size of the spots on the camera is 3-5 pixels, and the spots and the background plate are black and white;
the light emitted by the pulse laser source is adjusted into a plurality of uniform light beams after passing through the beam expanding and light homogenizing assembly, and the uniform light beams irradiate the background plate and uniformly illuminate the background plate.
Further, in step S1, the interval between the light guiding directions of the adjacent light guiding members needs to be adjusted to 18 to 36 °, and the flow field is located between the camera and the background plate.
Further, in step S1, the size of the background plate is determined in advance according to the size of the flow field and the position of the camera;
and according to the determined size of the background plate, selecting a focal length lens of the camera, setting a spot imaging size pixel, determining the physical size of the spot on the background plate, and then manufacturing the background plate.
Further, the pulsed laser light source illuminates the back plate either frontally or backwardly.
Further, the pulse width of the pulse laser light source is 5-100 ns; and the effective exposure time of the camera is the same as the pulse width time so as to obtain a transient flow field image of the flow field.
Further, the pulsed laser light source uniformly disperses the light to each light guide member through the plurality of light splitting members, respectively.
The embodiment of the invention has the beneficial effects that:
the method can firstly acquire images of a flow field by using a camera in a wind-cut state, so as to obtain a static background spot image of a background plate after the background plate penetrates through the flow field, and the background spot image is undistorted; and then, in a blowing state, acquiring an image of the background plate by using the camera again, so as to obtain a dynamic background speckle image of the background plate after the background plate penetrates through a flow field in the blowing state, wherein the density change exists due to the existence of the hypersonic shock wave flow field, and the background speckle image has distortion. Firstly, resolving displacement vectors of spots in static and dynamic background spot images in the same direction by a particle image cross-correlation algorithm, and then obtaining a projection result of the distribution of a quantitative refractive index field and a density field in each direction of a flow field to be measured by calculation according to the Fermat principle and the Grasston-Del law; and then reconstructing the three-dimensional density field distribution of the flow field to be measured by adopting a filtering back projection algorithm according to the density field projection result.
Through the design, the measuring method for calculating the density gradient based on the background speckle imaging and the cross-correlation algorithm has the characteristics of large field of view, quantification, simple device and low cost, can accurately measure the three-dimensional density field on the premise of simplifying the structure, has a wider application range, and can realize transient measurement of the hypersonic flow field.
In general, the hypersonic flow field three-dimensional density field measurement method provided by the embodiment of the invention improves the flow field display and measurement capability of complicated flow of the hypersonic flow field by comprehensively using the technologies of pulse laser illumination, multi-direction flow field projection data acquisition and back projection filtering reconstruction, and meets the increasing requirement of large-size refined flow field test.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a schematic system structure diagram of a measuring apparatus according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a light guide member according to an embodiment of the present invention.
Icon: the device comprises a 1-pulse laser light source, a 2-laser, a 3-light guide component, a 31-beam expanding and light homogenizing component, a 311-plano-concave lens, a 312-convex lens, a 313-transparent diffusion screen, a 32-background plate, a 4-camera, a 5-flow field, a 6-light splitting component, a 7-pulse signal generator, an 8-image acquisition computer and a 9-sealing tank.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships that the products of the present invention are conventionally placed in use, and are only used for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "parallel," "perpendicular," and the like do not require that the components be absolutely parallel or perpendicular, but may be slightly inclined. For example, "parallel" merely means that the directions are more parallel relative to "perpendicular," and does not mean that the structures are necessarily perfectly parallel, but may be slightly tilted.
Furthermore, the terms "horizontal", "vertical", "overhang" and the like do not imply that the components are required to be absolutely horizontal or overhang, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.
Examples
Referring to fig. 1 and fig. 2, the present embodiment provides a method for measuring a three-dimensional density field of a hypersonic flow field 5, including the following steps:
s1: in the wind-cut state, a flow field 5 is subjected to image acquisition by using a measuring device to obtain a static background spot image;
s2: under the blowing state, the flow field 5 is subjected to image acquisition by using the measuring device again to obtain a dynamic background spot image;
s3: solving displacement vectors of speckles in the static background speckle image and the dynamic background speckle image in the same direction by adopting a particle image cross-correlation algorithm;
s4: according to the Fermat principle and the Grasston-Diel law, the projection result of the distribution of the quantitative refractive index field and the density field in each direction of the flow field 5 to be measured can be obtained through calculation;
s5: and reconstructing the three-dimensional density field distribution of the flow field 5 to be measured by adopting a filtering back projection algorithm according to the projection result.
In this embodiment, in order to guarantee that the test process can not receive the influence of external air current, when testing, can go on in sealed jar body.
It should be noted that in the step S2, the air blowing state means that an air inlet is formed at the top of the sealed can 9, the air flow flows from top to bottom, and the direction of the air flow is perpendicular to the optical axis direction of the camera 4.
In a wind-stop state, firstly, the camera 4 is used for collecting images of the background plate 32, so that a static background spot image of the background plate 32 after penetrating through the flow field 5 is obtained, and the background spot image is free of distortion; then, in the blowing state, the camera 4 is used to perform image acquisition on the background plate 32 again, so as to obtain a dynamic background speckle image of the background plate 32 after passing through the flow field 5 in the blowing state, at this time, due to the existence of the hypersonic shock wave flow field 5, density change exists, and the background speckle image has distortion. Firstly, resolving displacement vectors of spots in static and dynamic background spot images in the same direction by a particle image cross-correlation algorithm, and then obtaining a projection result of the distribution of a quantitative refractive index field and a density field in each direction of the flow field 5 to be measured by calculation according to the Fermat principle and the Grasston-Del law; and then reconstructing the three-dimensional density field distribution of the flow field 5 to be measured by adopting a filtering back projection algorithm according to the density field projection result.
Through the design, the measuring method for calculating the density gradient based on the background speckle imaging and the cross-correlation algorithm has the characteristics of large field of view, quantification, simple device and low cost, can accurately measure the three-dimensional density field on the premise of simplifying the structure, has a wider application range, and can realize transient measurement of the hypersonic flow field 5.
In general, according to the method for measuring the three-dimensional density field of the hypersonic flow field 5 provided by the embodiment of the invention, the display and measurement capabilities of the flow field 5 with complex flow of the hypersonic flow field 5 are improved by comprehensively using the technologies of pulse laser illumination, multi-direction flow field 5 projection data acquisition and back projection filtering reconstruction, and the increasing test requirements of the large-size refined flow field 5 are met.
In this embodiment, the particle image cross-correlation algorithm is used to calculate the displacement vectors of the two images, and the speckle offset can be generally obtained by using a cross-correlation module in similar PIV image processing software, which is mainly based on the cross-correlation analysis of the images.
Specifically, the point s (k,1) in the static background speckle image can be taken as a diagnostic window for offset, the point t (k,1) in the dynamic background speckle image can be taken as an iterative window, and the window size is a × b, and the following normalized cross-correlation formula is used:
changing the value of R (m, n) along with the change of the position of the iteration window, wherein the position of the t (k,1) iteration window where the maximum value of R (m, n) is taken is the position of the diagnosis window s (k,1) in the dynamic background speckle image; (m, n) is the displacement of the diagnostic window s (k, 1).
In this embodiment, in step S4, according to the fermat principle, in the non-uniform medium, the light always travels along the path of the minimum optical path between two points, which can be expressed mathematically as:
δ∫n(x，y，z)ds＝0
where n (x, y, z) denotes the refractive index field distribution and s denotes the beam propagation path.
When light is transmitted in a non-uniform medium, according to the fermat principle, if the light offset is much smaller than the width of the flow field 5:
wherein C is a constant, related to the experimental configuration; Δ x, Δ y are the measured amounts of spot shift in different directions (i.e., equivalent to (m, n)). By calculating the partial derivatives of the entire displacement vector field in the x and y directions, the following poisson equation can be obtained:
the finite difference or finite element method can be utilized to solve through the equation, so that the quantitative refractive index field distribution of the projection integral effect of the measurement area is obtained, and the quantitative density field information is calculated through a Grasston-Del formula; as with the classical schlieren technique, the background schlieren technique reveals the relationship between the refractive index and density of a gas, and when a light ray is incident into a medium with a gradient refractive index, the light ray will be deflected in the direction of increasing refractive index, as known from grazing-dall's law, the relationship between the refractive index and density of a gas can be expressed by the following formula:
KG-D(λ)＝2.2244×10-4·(1+(6.7×10-8/λ)2)
wherein λ is the wavelength of light.
In this embodiment, in step S5, a filtered back-projection algorithm is adopted according to the projection result, and its theoretical basis is the central slice theorem: projection P of an image f (x, y) at viewing angle phiΦ(xr) Gives a two-dimensional Fourier transform of f (x, y)
The slice intersects the W1 axis at an angle phi and passes through the origin of coordinates, namely:
the image to be created is alpha (x, y), and its two-dimensional Fourier transform
According to the theorem of central slicing,
can be viewed at different angles by alpha (x, y)Projection P at angle phiΦ(xr) And (4) obtaining the one-dimensional Fourier transform.
In particular, the method comprises the following steps of,
an image to be built:
the second part of the above formula:
this partial projection data ρ (x)rPhi) is filtered by a filter function | ρ | ═ ξ [ h (x)r)]Filtering to obtain corrected projection g (x)rPhi) in xrRcos (θ - Φ) is the value of the suspected equation passing through a given point (r, θ), and the substitution back equation can be obtained:
the practical physical meaning of the method is that all filtered projection functions of fixed points (r, theta) in the range of phi 0-pi are subjected to back projection accumulation to obtain the pixel value of the point, and therefore the three-dimensional density field distribution of the flow field 5 to be measured is obtained.
Further, the measuring device comprises a pulse laser light source 1, a light guide member 3 and a camera 4, the light guide member 3 and the camera 4 are correspondingly arranged on two sides of the flow field 5, and light rays transmitted by the light guide member 3 coincide with an optical axis of the camera 4. Wherein the light-guiding member 3 is intended to enable the light emitted from the pulsed laser light source 1 to uniformly illuminate the background plate 32.
In the present embodiment, the pulsed laser light source 1 is obtained by a laser 2.
In this embodiment, the light guide member 3 includes a beam expanding and light homogenizing assembly 31 and a background plate 32, an optical axis of the camera 4 is perpendicular to the background plate 32, the background plate 32 has randomly distributed spots, an imaging size of the spots on the camera 4 is 3-5 pixels, and the spots and the background plate 32 are black and white;
the light emitted by the pulse laser source 1 is adjusted into a plurality of uniform light beams after passing through the beam expanding and light homogenizing assembly 31, and the uniform light beams irradiate on the background plate 32 and pass through the background plate 32 to enter the flow field 5.
In this embodiment, the beam expanding and dodging assembly 31 includes a plano-concave lens 311, a convex lens 312 and a transparent diffusion screen 313 which are arranged in parallel, wherein the convex lens 312 is located between the plano-concave lens 311 and the transparent diffusion screen 313. The light emitted from the pulse laser light source 1 first passes through the plano-concave lens 311 and is diffused into a plurality of light rays, and the plurality of light rays pass through the convex lens 312 and are uniformly diffused and then are dispersed by the transparent diffusion screen 313.
By the design, a single beam of light emitted by the pulse laser light source 1 can be transformed into a plurality of uniform beams of light through the beam expanding light assembly, and after the plurality of uniform beams of light irradiate on the background plate 32, part of the light passes through the background plate 32 and is shielded by spots on the background plate 32, so that a background spot image can be shot through the camera 4.
Further, in order to further improve the detection accuracy, in the present embodiment, a plurality of light guide members 3 and a plurality of cameras 4 are intentionally provided, the plurality of light guide members 3 and the plurality of cameras 4 are correspondingly distributed along the circumferential direction of the flow field 5, a plurality of light rays emitted by the pulsed laser light source 1 correspondingly pass through the plurality of light guide members 3 to illuminate the background plate 32, and a plurality of background speckle images are correspondingly captured by the plurality of cameras 4 to obtain a plurality of static background speckle images and a plurality of dynamic background speckle images.
It should be noted that the plurality of light guide members 3 and the plurality of cameras 4 are distributed along the circumferential direction of the flow field 5, which means that each light guide member 3 is provided with one camera 4 in the light direction thereof, and the light guide members 3 and the cameras 4 correspondingly arranged thereon are respectively arranged on both sides of the flow field 5, so as to ensure that the background plate 32 is captured by the cameras 4 through the flow field 5 to be measured.
Specifically, more than 10 light guide members 3 and cameras 4 may be provided in the present embodiment, thereby obtaining more accurate data.
Further, it is to be noted that the angular interval a between the light guiding directions of the adjacent light guiding members 3 is 18 to 36 °, and the flow field 5 is located between the camera 4 and the background plate 32. Because the cameras 4 and the light guide members 3 are in a one-to-one correspondence relationship, the interval between the optical axes of the adjacent cameras 4 (the optical axis refers to the optical axis of the camera 4 in each path of measurement direction, and the optical axis is coaxial with the connecting line of the center of the photosensitive surface of the camera 4, the center of the flow field 5 and the center of the background plate 32 and represents the measurement direction of the path) is the same as the interval between the optical axes of the adjacent light guide members 3 in the light guide direction.
It should be noted that, in step S1, before the static background speckle image is acquired, the interval between the light guiding directions of the adjacent light guiding members 3 needs to be adjusted in advance to ensure the data accuracy.
Further, in order to be able to determine the size of the background plate 32, in the present embodiment, in the step S1, the size of the background plate 32 is determined in advance according to the size of the flow field 5 and the position of the camera 4;
according to the determined size of the background plate 32, the focal length lens of the camera 4 is selected, the spot imaging size pixel is set, the physical size of the spot on the background plate 32 is determined, and then the background plate 32 is manufactured.
The purpose of this kind of design lies in, can select the appropriate focus lens of camera 4 according to the size of background board 32 to guarantee that camera 4 can be more clear when acquireing the background speckle image, thereby can guarantee that data is more accurate when follow-up information analysis.
Further, in order to ensure that the camera 4 can obtain a clearer background speckle image, in the present embodiment, the pulsed laser light source 1 illuminates the background plate 32 frontally or backwardly.
In addition, the pulse width of the pulse laser light source 1 is 5-100 ns; and the effective exposure time of the camera 4 is the same as the pulse width time to acquire a transient image of the flow field 5.
Further, in order to send a beam of light to each light guide member 3 through one pulse laser light source 1, in this embodiment, a plurality of beam splitting members 6 are added to disperse a single beam of light, so that the single beam of light can be split into a plurality of beams of light, and each beam of light can correspond to each light guide member 3.
In the present embodiment, the spectroscopic member 6 may employ a plurality of mirrors, 1: 1 light splitting sheet, 1: 2 splitting wedge and 1: 3 light splitting wedges and the like, and particularly, the adaptability adjustment is required to be carried out according to the number of the light guide members 3; the use of the beam splitting means 6 for dispersing and transmitting the single light beam is conventional in the art and will not be described herein.
By adopting the design, the single light can be dispersed and transmitted by the light splitting component 6, and the intensity of each light can be ensured to be the same.
Further, it is to be noted that, before the step of S1, each detection route needs to be arranged according to the number of the light guide members 3 actually provided, in order to ensure the accuracy of detection.
In this embodiment, a pulse signal generator 7 is also specially added for convenience of control, wherein the laser 2 and the plurality of cameras 4 are respectively in communication connection with the pulse signal generator 7. The pulse signal generator 7 sends pulse signals to the laser 2 and the cameras 4 at the same time, and the cameras 4 simultaneously acquire background speckle images when the pulse laser light source 1 is controlled to illuminate the background plate 32.
In addition, background speckle image information acquired by the plurality of cameras 4 can be fed back in time, an image acquisition computer 8 is specially added in the embodiment, the plurality of cameras 4 are respectively in communication connection with the image acquisition computer 8 to send acquired background speckle images to the image acquisition computer 8 in time, analysis of static background speckle images and dynamic background speckle images is performed through the computer, and then calculation is performed to reconstruct three-dimensional density field distribution of the flow field 5 to be measured.
In conclusion, the display and measurement capabilities of the flow field 5 with complicated flow of the hypersonic flow field 5 are improved by comprehensively using the technologies of pulse laser illumination, multi-direction flow field 5 projection data acquisition and back projection filtering reconstruction, and the increasing test requirements of large-size refined flow fields 5 are met.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. A method for measuring a three-dimensional density field of a hypersonic flow field is characterized by comprising the following steps:
s1: in the wind-cut state, a flow field is subjected to image acquisition by using a measuring device to obtain a static background spot image;
s2: under the blowing state, the flow field is subjected to image acquisition by using the measuring device again to obtain a dynamic background spot image;
s3: solving displacement vectors of speckles in the static background speckle image and the dynamic background speckle image in the same direction by adopting a particle image cross-correlation algorithm;
s4: according to the Fermat principle and the Grasston-Diel law, the projection result of the distribution of the quantitative refractive index field and the density field in each direction of the flow field to be measured can be obtained through calculation;
s5: and reconstructing the three-dimensional density field distribution of the flow field to be measured by adopting a filtering back projection algorithm according to the projection result.
2. The measuring method according to claim 1, wherein the measuring device comprises a pulsed laser light source, a light guide member and a camera, the light guide member and the camera are correspondingly arranged on two sides of the flow field, and light rays transmitted by the light guide member are coincident with an optical axis of the camera.
3. The measuring method according to claim 2, wherein the plurality of light guide members and the plurality of cameras are distributed along the circumferential direction of the flow field, and the plurality of wide light rays emitted by the pulsed laser light source enter the flow field after passing through the plurality of light guide members correspondingly, and the plurality of cameras are used for shooting background spot images correspondingly to obtain a plurality of static background spot images and dynamic background spot images.
4. The measurement method according to claim 3, wherein the light guide member comprises a beam expanding and dodging assembly and a background plate, the optical axis of the camera is perpendicular to the background plate, the background plate has randomly distributed spots, the imaging size of the spots on the camera is 3-5 pixels, and the spots and the background plate are black and white;
the light emitted by the pulse laser source is adjusted into a plurality of uniform light beams after passing through the beam expanding and light homogenizing assembly, and the uniform light beams irradiate the background plate and uniformly illuminate the background plate.
5. The measuring method according to claim 4, wherein in step S1, the interval between the light guiding directions of the adjacent light guiding members is adjusted to 18-36 °, and the flow field is located between the camera and the background plate.
6. The measuring method according to claim 4, wherein in the step S1, the size of the background plate is determined in advance according to the size of the flow field and the position of the camera;
and according to the determined size of the background plate, selecting a focal length lens of the camera, setting a spot imaging size pixel, determining the physical size of the spot on the background plate, and then manufacturing the background plate.
7. The measurement method according to claim 6, wherein the pulsed laser light source illuminates the back plate with front or back light.
8. The measuring method according to claim 2, wherein the pulse width of the pulsed laser light source is 5-100 ns; and the effective exposure time of the camera is the same as the pulse width time so as to obtain a transient flow field image of the flow field.
9. The measuring method according to claim 2, wherein the pulsed laser light source disperses the light uniformly to each light guide member through a plurality of light splitting members, respectively.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113639955A (en) * | 2021-10-15 | 2021-11-12 | 中国空气动力研究与发展中心计算空气动力研究所 | Device for measuring concave panel boundary layer disturbance |
| CN114119747A (en) * | 2021-11-23 | 2022-03-01 | 四川大学 | Three-dimensional flow field flow display method based on PMD wavefront detection |
| CN114755449A (en) * | 2022-06-14 | 2022-07-15 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Particle image speed measurement distortion correction device and method |
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| CN116399551A (en) * | 2023-06-06 | 2023-07-07 | 中国航空工业集团公司沈阳空气动力研究所 | Model three-dimensional density field measurement method for hypersonic wind tunnel |
| CN116519257A (en) * | 2023-04-19 | 2023-08-01 | 南京航空航天大学 | Three-dimensional flow field testing method and system based on double-view background schlieren of single-light-field camera |
| CN116718344A (en) * | 2023-08-10 | 2023-09-08 | 中国空气动力研究与发展中心高速空气动力研究所 | Multi-parameter thrust vector jet optical calibration method |
| CN117782517A (en) * | 2023-12-05 | 2024-03-29 | 南京航空航天大学 | Two-dimensional flow field testing method and system based on multi-camera background schlieren |
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| CN113639955A (en) * | 2021-10-15 | 2021-11-12 | 中国空气动力研究与发展中心计算空气动力研究所 | Device for measuring concave panel boundary layer disturbance |
| CN113639955B (en) * | 2021-10-15 | 2022-01-04 | 中国空气动力研究与发展中心计算空气动力研究所 | Device for measuring concave panel boundary layer disturbance |
| CN114119747A (en) * | 2021-11-23 | 2022-03-01 | 四川大学 | Three-dimensional flow field flow display method based on PMD wavefront detection |
| CN114838900A (en) * | 2022-05-09 | 2022-08-02 | 中山大学 | Optical compensation method and device for wind tunnel experiment |
| CN114755449A (en) * | 2022-06-14 | 2022-07-15 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Particle image speed measurement distortion correction device and method |
| CN116519257A (en) * | 2023-04-19 | 2023-08-01 | 南京航空航天大学 | Three-dimensional flow field testing method and system based on double-view background schlieren of single-light-field camera |
| CN116519257B (en) * | 2023-04-19 | 2024-05-24 | 南京航空航天大学 | Three-dimensional flow field testing method and system based on double-view background schlieren of single-light-field camera |
| CN116399551A (en) * | 2023-06-06 | 2023-07-07 | 中国航空工业集团公司沈阳空气动力研究所 | Model three-dimensional density field measurement method for hypersonic wind tunnel |
| CN116399551B (en) * | 2023-06-06 | 2023-08-04 | 中国航空工业集团公司沈阳空气动力研究所 | Model three-dimensional density field measurement method for hypersonic wind tunnel |
| CN116718344A (en) * | 2023-08-10 | 2023-09-08 | 中国空气动力研究与发展中心高速空气动力研究所 | Multi-parameter thrust vector jet optical calibration method |
| CN116718344B (en) * | 2023-08-10 | 2023-10-27 | 中国空气动力研究与发展中心高速空气动力研究所 | Multi-parameter thrust vector jet optical calibration method |
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