CN103808958A - Method and device for measuring flow velocity of viscous sublayer of open channel turbulent flow - Google Patents
Method and device for measuring flow velocity of viscous sublayer of open channel turbulent flow Download PDFInfo
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Abstract
The invention relates to a method and a device for measuring a flow velocity of viscous sublayer of an open channel turbulent flow and belongs to the technical field of open channel experiments. The device comprises a camera, a lens, a continuous laser, a beam splitter prism and a computer; the device is characterized by further comprising a length adjustable close-up cavity and a plano-convex cylindrical lens; the continuous laser is arranged under the base plate of an open channel water tank to be measured, the output optical axis of the continuous laser vertically faces the base plate, and the beam splitter prism and the plano-convex cylindrical lens are orderly arranged on the output optical axis of the laser; the camera is arranged outside the sidewall of the open channel water tank, connected with the lens through the length adjustable close-up cavity, the lens is aligned to a rectangular laser sheet, and the computer is connected with the camera through a connecting wire and processes trace particle images picked up by the camera to obtain the flow velocity of the viscous sublayer of the open channel turbulent flow. The method comprises two parts of adjusting the device and picking up images by using the device, and measuring the flow velocity. The device is high in frequency, high in accuracy, convenient to use and the like.
Description
Technical field
The invention belongs to open channel experimental technique field, particularly the improvement to Particle-beam Tracing velocity measuring technique.
Background technology
In Turbulence in Open channel Flow, the viscous sublayer of near-bed is very important, is the source of Turbulence in Open channel Flow shear stress and vorticity, and plays a key effect in the processes such as the generation of turbulent fluctuation and development, heat and mass.But, the flow performance in this region is measured to extremely difficult, main difficult point and be that the physical size of viscous sublayer is minimum, and current gradient in region is very big.For example, be 5cm for the depth of water, the Turbulence in Open channel Flow that frictional resistance Reynolds number is 1000, viscous sublayer thickness is about 0.25mm, and flow velocity rapidly increases to 20% of mean velocity in section in this region from 0.
Traditional contact measurement method, as Pitot tube, hotting mask heated filament etc. not only can interference flowing fields, and the size of measuring body itself is all in millimeter magnitude, cannot reach the requirement of measurement viscous sublayer.The contactless measurement of developed recently maturation as acoustic Doppler velocimetry, Doppler laser velocimeter, particle imaging velocity measuring technique (PIV) and Particle-beam Tracing velocity measuring technique (PTV) etc., all can record accurate data in routine flows.But the measurement body size of acoustic Doppler velocimetry is in millimeter magnitude, cannot high-acruracy survey viscous sublayer; The yardstick of the current micelle that Doppler laser velocimeter is surveyed is about 0.1mm under ideal conditions, in 0.25mm, obtains 3 measurement points to multipotency, is difficult to obtain the velocity flow profile of viscous sublayer; All there is the problem of bed surface reflectance ultrasound and laser in acoustic Doppler velocimetry and Doppler laser velocimeter simultaneously, lower in measuring accuracy in bed surface 1mm; Particle imaging velocity measuring technique is because the average information that uses interpretation window obtains point velocity, therefore there is larger measuring error in the great region of this class current gradient of viscous sublayer.
The device of existing Particle-beam Tracing velocity measuring technique comprises PTV video camera, camera lens and LASER Light Source, its ultimate principle is spreading trace particle in water body, trace particle is followed water sports, use LASER Light Source to illuminate the trace particle of a plane in water body, laser beam is divided into fanning strip light by the general spectroscope that uses, and the sheet optical width of measured zone is more than 20cm.Adopt PTV video camera to take the image of the bright trace particle of fanning strip illumination, the filming frequency of PTV camera is generally less than 1000/s.With the method for its device velocity measurement be that first front and back two pictures that the trace particle of a plane in water body is taken are continuously chosen gray threshold and carried out binaryzation, obtain particle picture; Conventional gray threshold determines that method has simple greyscale transformation method, nonzero element to get a method, fixed threshold method, two fixed threshold method (Li Danxun etc., Particle-beam Tracing velocity measuring technique, Science Press, 2012) and large Tianjin method (Otsu N.A threshold selection method from gray-level histograms.Automatica[J], 1975,11 (285-296): 23-27) etc., these methods are once and calculate and directly obtain gray threshold.Obtain using thresholding method to obtain the region of each particle after binaryzation picture, then obtain centre of form coordinate to represent each particle position according to the region of each particle, finally adopt coupling probability method (Li Danxun etc., Particle-beam Tracing velocity measuring technique, Science Press, 2012) particle position in two pictures is mated, obtain particle in the displacement of taking in two photo time intervals according to the centre of form difference of pairing particle, displacement obtains the movement velocity of particle position water body divided by the time interval.Particle-beam Tracing velocity measuring technique can obtain data accurately in the region of high flow rate gradient.But ordinary particle spike velocity measuring technique uses conventional image capture method, the distance (image distance) of camera lens and PTV camera is in the scope of lens design.It is enough bright that this conventional image capture method can guarantee to take the particle picture obtaining, and noise is less, simultaneously aberration minimum.But the resolution of conventional image capture method gained picture is low, cause common PTV method cannot meet the requirement that viscous sublayer is measured.
Summary of the invention
The object of the invention is the deficiency for overcoming existing open channel flow-speed measurement method, a kind of method and device of measuring Turbulence in Open channel Flow viscous sublayer flow velocity is provided.The present invention utilizes the ultimate principle of PTV method, uses microspur camera technique to be met viscous sublayer and measures the high-resolution pictures requiring, and solve the problems such as picture signal to noise ratio (S/N ratio) is extremely low, aberration is large.The present invention has that frequency is high, resolution is high and precision advantages of higher
Technical characterstic of the present invention and beneficial effect are as follows:
The present invention adopts microspur camera technique to increase the resolution of picture, for the variety of issue of gained picture under high resolving power condition, adopt threshold value process of iteration to determine binary-state threshold, solve the low problem of picture signal to noise ratio (S/N ratio), set particle picture Shape Indexes, reject the serious particle of aberration, adopt intercept method to calculate particle picture centre of form coordinate, avoid aberration on calculating the impact of particle position.The present invention has the advantages such as survey frequency is high, precision is high, easy to use.
Accompanying drawing explanation
Fig. 1 is apparatus of the present invention composition schematic diagram;
Fig. 2 is the flow-speed measurement method FB(flow block) in the present invention;
Fig. 3 is embodiment of the present invention installation composition schematic diagram;
Fig. 4 is embodiments of the invention viscous sublayer velocity flow profile.
Embodiment
Describe each related detailed problem in technical solution of the present invention in detail below in conjunction with drawings and Examples.Be to be noted that described embodiment is only intended to be convenient to the understanding of the present invention, and it is not played to any restriction effect.
As shown in Figure 1, this device comprises video camera 1, camera lens 3, continuous wave laser 4, Amici prism 5 and computing machine 7 to a kind of device of measuring Turbulence in Open channel Flow viscous sublayer flow velocity of the present invention; It is characterized in that, also comprise close-shot chamber 2, the plano-convex cylindrical lens 6 of adjustable length; Wherein, described continuous wave laser 4 is arranged under the base plate of open channel tank 10 to be measured, and the output optical axis of this laser instrument is vertically towards base plate, and described Amici prism 5, plano-convex cylindrical lens 6 are successively set on the output optical axis of laser instrument, the light beam of laser instrument output is adjusted into a rectangular laser sheet light 9; Described video camera 1 is arranged on outside the limit wall of open channel tank 10, this video camera is connected with camera lens 3 by the close-shot chamber 2 of adjustable length, camera lens 3 is aimed at described rectangular laser sheet light 9, the trace particle image illuminating to take rectangular laser sheet light 9, described computing machine 7 is connected by connecting line 8 with video camera 1, the trace particle image that video camera 1 is taken is processed, to obtain Turbulence in Open channel Flow viscous sublayer flow velocity.The shooting frame frequency of described video camera 1 is greater than 3000/second; Described close-shot chamber 2 can be elastic, adjusts the distance between camera lens 3 and video camera 1; Described camera lens 3 is darkroom enlarging lens, and its image field is straight, and the aberration of gained picture is little compared with common lens; The continuous wave laser (the higher gained picture of power is brighter, and result is better) that described continuous wave laser 4 is a power 8-20W; The light splitting angle of described Amici prism 5 is 8-15 °, and continuous wave laser 4 is given off laser beam and is diffused as fan-shaped laser sheet optical; Described plano-convex cylindrical lens 6 spreads Amici prism 5 to the fan-shaped laser sheet optical of gained and is adjusted into rectangular laser sheet light 9; The width of described rectangular laser sheet light 9, below 30mm, so that concentrate laser energy, improves brightness of illumination; Described computing machine 7 is connected with video camera 1 by connecting line 8, controls video camera 1 pictures taken.
The present invention adopts a kind of method of measuring Turbulence in Open channel Flow viscous sublayer flow velocity of said apparatus, comprises the adjustment of device and measurement two parts of shooting and flow velocity, and the adjustment of device and shooting, with reference to figure 1, comprise the following steps:
Step I: adjust laser sheet optical: open continuous wave laser 4, adjust the spacing between continuous wave laser 4, Amici prism 5, plano-convex cylindrical lens 6, continuous wave laser 4 is given off laser beam and is adjusted into rectangular laser sheet light 9, integrated moving continuous wave laser 4, the position of Amici prism 5, plano-convex cylindrical lens 6, makes rectangular laser sheet light 9 illuminate region to be measured;
Step II: adjust camera lens and camera: the demarcation thing with half millimeter of scale is placed in the position of rectangular laser sheet light 9 in tank, closes continuous wave laser 4; Limit wall by camera lens 3 near open channel tank 10, the position of fixed lens 3, adjust the position of video camera 1, the length in close-shot chamber 2 is followed the variation of video camera 1 position and is changed, until video camera 1 obtains clear picture, read the length of the demarcation thing now photographing, calculating chart chip resolution (the picture pixel that 1mm is corresponding), adjust afterwards camera lens 3 and the distance of tank limit wall and the position of video camera 1, until photo resolution reaches experiment setting value; After adjusting, record photo resolution, take out demarcation thing;
Step II I: pictures taken; Adjust the streamflow regime in open channel tank 10, meet after requirement of experiment, at open channel tank 10 upstream spreading trace particles (hereinafter to be referred as particle), after Particle Circulation is stable, open continuous wave laser 4 and video camera 1,
Start to take continuously the picture that multiple show particle picture, the total number of picture is Num
total(Num
totalbe greater than 100, Num
totalless, follow-up fluid-velocity survey required time is fewer, but acquired results precision is lower; Num
totallarger, fluid-velocity survey required time is more, and acquired results precision is higher), and captured whole pictures are entered to computing machine 7 by taking sequential storage, giving picture sequence numbers K(K for all pictures according to shooting order is the positive integer since 1); After shooting completes, close continuous wave laser 4 and video camera 1.
As shown in Figure 2, whole process completes in computing machine 7, comprises the following steps in the measurement of flow velocity:
Steps A: judge whether picture sequence numbers K is greater than Num
total-1, if K>Num
total-1, enter step O, otherwise, enter step B;
Step B: read in the picture that picture sequence numbers is K;
Step C: adopt large Tianjin method to determine the initial gray threshold T of the binaryzation of picture K
i, i=0(i is threshold value iterative loop ordinal number, is nonnegative integer; Microspur camera technique increases picture magnification, but also can cause that picture is dimmed, signal to noise ratio (S/N ratio) is low, directly uses large Tianjin method to determine that gray threshold can be mistaken for particle picture by noise, so passing threshold process of iteration of the present invention obtains reasonable gray threshold);
Step D: use gray threshold T
ito picture K binaryzation;
Step e: the particle number N after extraction binaryzation in picture K
i;
Step F: judge N
iwhether be greater than setting threshold N
maxif, N
i>N
max, carry out step G; Otherwise, carry out step J(50<N
max<300, N
maxlarger, the population identifying from picture is more, and the probability that ground unrest is mistaken for to particle picture is also larger; Otherwise, N
maxless, the population identifying from picture is fewer, and the probability that ground unrest is mistaken for to particle picture is also less);
The value of step G:i increases by 1, determines new binary-state threshold T
ias the formula (1):
Step H: adopt binary-state threshold T
ito picture K binaryzation;
Step I: particle number N after extraction binaryzation
i, return to step F;
Step J: read in picture K+1, use threshold value T
ito picture K+1 binaryzation;
Step K: reject the serious particle picture of aberration, adopt criterion as the formula (2) to reject the serious particle picture of aberration in picture K, the K+1 after binaryzation
Wherein, the ovality index that σ is single particle, L
maxfor the maximum length of this particle picture, L
minfor the minimum length of this particle picture (σ is less, illustrates that particle picture is more close to circle, and σ is larger, illustrates that particle shape gets over prolate, and aberration is more serious); ε is circularity index, d
0for the circular diameter (ε is larger, illustrates that the region of particle picture interior void is more, does not more enrich, and aberration is more serious) equating with particle picture area; Τ
σwith Τ
εfor threshold value (the 5< Τ setting
σ<10,10< Τ
ε<50, threshold value is larger, and the particle of rejecting is fewer, but final gained flow velocity precision is lower, and threshold value is less, and the particle of rejecting is more, corresponding flow velocity precision is higher);
Step L: adopt intercept method to calculate particle picture centre of form coordinate, calculate the centre coordinate of each particle picture in binaryzation picture K, K+1 as the formula (3):
Wherein I (P) is the gray-scale value at P point place, I
peakfor the maximal value of gray scale within the scope of particle picture; N is the total pixel number (after formula (3) is calculated, only the light of particle picture participates in the computing of centre coordinate, has avoided aberration to calculating the impact of particle position) that participates in computing;
Step M: use the particle in coupling probability method coupling picture K, K+1, the distance between pairing particle centre coordinate is particle displacement, and particle displacement obtain the movement velocity of particle divided by the time interval of video camera 1 pictures taken K, K+1;
Step N: the Particles Moving speed record that step M is obtained is in array Velocity, and corresponding particle centre coordinate is recorded in array Position, and the value of K increases by 1, returns to steps A;
Step O: calculate velocity flow profile, find minimum value PL and the maximal value PM of vertical coordinate in array Position, take Δ as spacing, the scope between PM and PL is divided into some regions, each region is a measuring point, for each region, in array Position, find all centre coordinates to drop on the particle in this region, from Velocity array, obtain the movement velocity of these particles, and obtain the mean value of movement velocity, as the average velocity to this measuring point, the average velocity of all measuring points had both formed velocity flow profile (2< Δ <15, Δ is larger, final measuring point number is fewer, but the region of each measuring point is larger, drop on particle number in measuring point more, the error of mean flow rate is less, Δ is less, and final measuring point number is more, but the region of each measuring point is less, and the error of mean flow rate is larger).
Take Turbulence in Open channel Flow viscous sublayer experiments of measuring as embodiment, detailed implementation process of the present invention is described below.The present embodiment apparatus structure, as Fig. 3, this device comprises video camera 1, close-shot chamber 2, camera lens 3, continuous wave laser 4, Amici prism 5, plano-convex cylindrical lens 6, computing machine 7, connecting line 8; Test is carried out in the open channel tank 10 of long 20m, wide 30cm, and open channel tank 10 sidewalls and base plate are ultra-clear glasses.Experiment adopts PSP trace particle, particle diameter 5 μ m, density 1.03g/mm
3.The model of video camera 1 is IDT NR5-S2, and shooting speed is 4500/s; Camera lens 3 is darkroom enlarging lens, and model is APO-Rodagon-N50/2.8; Camera lens 3 is 130mm apart from the distance of rectangular laser sheet light 9.Close-shot chamber 2 is close-shot bellows, and flexible scope is 0-100mm, and this test is set as 98mm.Continuous wave laser 4 is Laser Quantum FINESSE-16 type continuous wave laser, 16 watts of laser powers.Amici prism 5 for light splitting angle be the Bao Weier prism of 8 °, the focal length of plano-convex cylindrical lens 6 is 220mm, thickness is 10mm, length 50mm, the width of rectangular laser sheet light 9 is 30mm.Computing machine 7 is Dell Precision T7610 workstation.The netting twine of connecting line 8 for configuring with video camera 1.
The resolution of requirement of experiment picture is 223 pixels/mm.
The measuring method of the present embodiment comprises the adjustment of device and measurement two parts of shooting and flow velocity, and the adjustment of device and shooting, with reference to figure 3, comprise the following steps:
Step I: adjust laser sheet optical: open continuous wave laser 4, adjust the distance of spacing between Amici prism 5, plano-convex cylindrical lens 6 and the two and continuous wave laser 4, continuous wave laser 4 is given off laser beam and is adjusted into rectangular laser sheet light 9, integrated moving continuous wave laser 4, the position of Amici prism 5, plano-convex cylindrical lens 6, makes rectangular laser sheet light 9 illuminate region to be measured;
Step II: adjust camera lens and camera: the steel ruler with half millimeter of scale is placed in the position of rectangular laser sheet light 9 in tank, closes continuous wave laser 4; By camera lens 3 near tank limit wall, the position of fixed lens 3, adjust video camera 1 position, now the length in close-shot chamber 2 is followed the variation of video camera 1 position and is changed, until video camera 1 obtains clear picture, read the length of the steel ruler now photographing, calculating chart chip resolution (the picture pixel that 1mm is corresponding), adjust afterwards camera lens 3 and the distance of tank limit wall and the position of video camera 1 position, until photo resolution reaches 223 pixels/mm; After adjusting, record photo resolution, take out steel ruler;
Step II I: pictures taken; Adjust the streamflow regime in open channel tank 10, meet after requirement of experiment, at open channel tank 10 upstream spreading PTV trace particles, after stable circulation, open continuous wave laser 4 and video camera 1, setting video camera 1 filming frequency is 4500/second, starts continuous pictures taken, the total number Num of picture
total=5000, and captured whole pictures are entered to computing machine 7 by taking sequential storage; Giving picture sequence numbers K(K for all pictures according to shooting order is the positive integer since 1); After shooting completes, close continuous wave laser 4 and video camera 1.
The measurement of flow velocity comprises the following steps:
Steps A: judge whether picture sequence numbers K is greater than Num
total-1=4999, if K>4999 enters step O, otherwise, enter step B;
Step B: read in the picture that picture sequence numbers is K;
Step C: adopt large Tianjin method to determine the initial gray threshold T of the binaryzation of picture K
i, i=0(i is threshold value iterative loop ordinal number, is nonnegative integer);
Step D: use gray threshold T
ito picture K binaryzation;
Step e: the particle number N after extraction binaryzation in picture K
i;
Step F: judge N
iwhether be greater than setting threshold N
max=150, if N
i>N
max, carry out step G; Otherwise, carry out step J;
The value of step G:i increases by 1, determines new binary-state threshold T according to formula (1)
i
Step H: adopt binary-state threshold T
ito picture K binaryzation;
Step I: particle number N after extraction binaryzation
i, return to step F;
Step J: read in picture K+1, use threshold value T
ito picture K+1 binaryzation;
Step K: use formula (2) criterion is rejected the serious particle of aberration in picture K, the K+1 after binaryzation wherein, Τ
σwith Τ
εfor threshold value,, Τ
σ=5, Τ
ε=25;
Step L: use formula (3) is calculated the centre coordinate of each particle in binaryzation picture K, K+1;
Step M: use the particle in coupling probability method coupling picture K, K+1, the distance between pairing particle central point is particle displacement, and particle displacement obtain the movement velocity of particle divided by the time interval of video camera 1 pictures taken K, K+1;
Step N: the Particles Moving speed record that step M is obtained is in array Velocity, and corresponding particle centre coordinate is recorded in array Position, and the value of K increases by 1, returns to steps A;
Step O: calculate velocity flow profile, find minimum value PL=0.5 and the maximal value PM=107.2 of vertical coordinate in array Position, take Δ=3 as spacing, the scope between PM and PL is divided into 36 regions, each region is a measuring point, for each region, in array Position, find all centre coordinates to drop on the particle in this region, from Velocity array, obtain the movement velocity of these particles, and obtain the mean value of movement velocity, as the average velocity to this measuring point, the average velocity of all measuring points had both formed velocity flow profile.
Fig. 4 is the viscous sublayer velocity flow profile that the present embodiment records, and has obtained 20 measuring points below 0.25mm, far above the spatial resolution of other measurement means, and the flow velocity distribution that is in line, coincide good with notional result.
Claims (4)
1. measure a device for Turbulence in Open channel Flow viscous sublayer flow velocity, this device comprises video camera, camera lens, continuous wave laser, Amici prism and computing machine; It is characterized in that, also comprise close-shot chamber, the plano-convex cylindrical lens of adjustable length; Wherein, described continuous wave laser is arranged under the base plate of open channel tank to be measured, and the output optical axis of this laser instrument is vertically towards base plate, and described Amici prism, plano-convex cylindrical lens are successively set on the output optical axis of laser instrument, the light beam of laser instrument output is adjusted into a rectangular laser sheet light; Described video camera is arranged on outside the limit wall of open channel tank, this video camera is connected with camera lens by the close-shot chamber of adjustable length, rectangular laser sheet light described in alignment lens, to take the bright trace particle image of rectangular laser sheet illumination, described computing machine is connected by connecting line with video camera, the trace particle image that video camera is taken is processed, to obtain Turbulence in Open channel Flow viscous sublayer flow velocity.
2. install as claimed in claim 1, it is characterized in that, the shooting frame frequency of described video camera is greater than 3000/second.
3. install as claimed in claim 1, it is characterized in that, described camera lens is darkroom enlarging lens, and its image field is straight.
4. adopt a kind of method of measuring Turbulence in Open channel Flow viscous sublayer flow velocity of device as claimed in claim 1, it is characterized in that, the method comprises the adjustment of device and measurement two parts of shooting and flow velocity; The adjustment of described device and shooting, comprise the following steps:
Step I: adjust laser sheet optical: open continuous wave laser, adjust the spacing between continuous wave laser, Amici prism, plano-convex cylindrical lens, continuous wave laser is given off laser beam and is adjusted into rectangular laser sheet light, integrated moving continuous wave laser, the position of Amici prism, plano-convex cylindrical lens, makes the bright region to be measured of rectangular laser sheet illumination;
Step II: adjust camera lens and camera: the demarcation thing with half millimeter of scale is placed in the position of rectangular laser sheet light in tank, closes continuous wave laser; Limit wall by camera lens near open channel tank, the position of fixed lens, adjust the position of video camera, the length in close-shot chamber is followed the variation of camera position and is changed, until video camera obtains clear picture, read the length of the demarcation thing now photographing, calculating chart chip resolution, adjust afterwards camera lens and the distance of tank limit wall and the position of video camera, until photo resolution reaches experiment setting value; After adjusting, record photo resolution, take out demarcation thing;
Step II I: pictures taken; Adjust the streamflow regime in open channel tank, meet after requirement of experiment, at the particle of open channel tank upstream spreading spike, after Particle Circulation is stable, open continuous wave laser and video camera, start to take continuously the picture that multiple show particle picture, the total number of picture is Num
total; , and captured whole pictures are entered to computing machine by taking sequential storage, for all pictures are given picture sequence numbers K according to shooting order, K is the positive integer since 1; After shooting completes, close continuous wave laser and video camera;
The measurement of described flow velocity, comprises the following steps:
Steps A: judge whether picture sequence numbers K is greater than Num
total-1, if K>Num
total-1, enter step O, otherwise, enter step B;
Step B: read in the picture that picture sequence numbers is K;
Step C: adopt large Tianjin method to determine the initial gray threshold T of the binaryzation of picture K
i, i=0, i is threshold value iterative loop ordinal number, is nonnegative integer;
Step D: use gray threshold T
ito picture K binaryzation;
Step e: the particle number N after extraction binaryzation in picture K
i;
Step F: judge N
iwhether be greater than setting threshold N
maxif, N
i>N
max, carry out step G; Otherwise, carry out step J;
The value of step G:i increases by 1, determines new binary-state threshold T
ias the formula (1):
Step H: adopt binary-state threshold T
ito picture K binaryzation;
Step I: particle number N after extraction binaryzation
i, return to step F;
Step J: read in picture K+1, use threshold value T
ito picture K+1 binaryzation;
Step K: adopt criterion as the formula (2) to reject the serious particle picture of aberration in picture K, the K+1 after binaryzation:
Wherein, the ovality index that σ is single particle, L
maxfor the maximum length of this particle picture, L
minfor the minimum length of this particle picture; ε is circularity index, d
0for the circular diameter equating with particle picture area; Τ
σwith Τ
εfor the threshold value of setting;
Step L: adopt intercept method to calculate particle picture centre of form coordinate, calculate the centre coordinate of each particle picture in binaryzation picture K, K+1 as the formula (3):
Wherein I (P) is the gray-scale value at P point place, I
peakfor the maximal value of gray scale within the scope of particle picture; N is the total pixel number that participates in computing;
Step M: use the particle in coupling probability method coupling picture K, K+1, the distance between pairing particle centre coordinate is particle displacement, and particle displacement obtain the movement velocity of particle divided by the time interval of video camera 1 pictures taken K, K+1;
Step N: the Particles Moving speed record that step M is obtained is in array Velocity, and corresponding particle centre coordinate is recorded in array Position, and the value of K increases by 1, returns to steps A;
Step O: calculate velocity flow profile, find minimum value PL and the maximal value PM of vertical coordinate in array Position, take Δ as spacing, the scope between PM and PL is divided into some regions, each region is a measuring point, for each region, in array Position, find all centre coordinates to drop on the particle in this region, from Velocity array, obtain the movement velocity of these particles, and obtain the mean value of movement velocity, as the average velocity to this measuring point, the average velocity of all measuring points had both formed velocity flow profile, 2< Δ <15.
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| CN104133078A (en) * | 2014-07-30 | 2014-11-05 | 清华大学 | Three-dimensional flow field high-frequency measurement device based on light sheet scanning of particle pictures and method of three-dimensional flow field high-frequency measurement device |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080297763A1 (en) * | 2007-03-30 | 2008-12-04 | Jean Herzberg | Single axis scanning piv system and method |
| CN102393193A (en) * | 2011-10-12 | 2012-03-28 | 清华大学 | High frequency image acquisition system for measuring flow rate |
| CN103293333A (en) * | 2013-05-10 | 2013-09-11 | 东南大学 | Two-dimensional flow velocity field measurement method and device of interlaced scanning CCD (charge coupled device) |
| US20130242286A1 (en) * | 2012-03-16 | 2013-09-19 | Honda Motor Co., Ltd. | Particle image velocimetry system for three-dimensional space |
-
2014
- 2014-01-26 CN CN201410037928.7A patent/CN103808958B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080297763A1 (en) * | 2007-03-30 | 2008-12-04 | Jean Herzberg | Single axis scanning piv system and method |
| CN102393193A (en) * | 2011-10-12 | 2012-03-28 | 清华大学 | High frequency image acquisition system for measuring flow rate |
| US20130242286A1 (en) * | 2012-03-16 | 2013-09-19 | Honda Motor Co., Ltd. | Particle image velocimetry system for three-dimensional space |
| CN103293333A (en) * | 2013-05-10 | 2013-09-11 | 东南大学 | Two-dimensional flow velocity field measurement method and device of interlaced scanning CCD (charge coupled device) |
Non-Patent Citations (2)
| Title |
|---|
| 许联锋: "水气两相流动的数字图像测量方法及应用研究", 《中国优秀博硕士学位论文全文数据库（博士） 工程科技Ⅱ辑》, no. 2, 15 June 2005 (2005-06-15) * |
| 钟强等: "提高PIV片光源质量的研究", 《实验力学》, vol. 28, no. 6, 31 December 2013 (2013-12-31) * |
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| CN104133078B (en) * | 2014-07-30 | 2016-08-17 | 清华大学 | Three-dimensional flow field HF measurement system based on sheet photoscanning particle picture and method thereof |
| CN107449936A (en) * | 2017-09-18 | 2017-12-08 | 三峡大学 | Utilize the device and its method for drafting of PIV technologies measurement fish body tail vorticity field |
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