CN107907296A - The water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration - Google Patents
The water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration Download PDFInfo
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- CN107907296A CN107907296A CN201711020790.XA CN201711020790A CN107907296A CN 107907296 A CN107907296 A CN 107907296A CN 201711020790 A CN201711020790 A CN 201711020790A CN 107907296 A CN107907296 A CN 107907296A
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Abstract
The present invention relates to a kind of water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration, belong to ship and submarine navigation device engineering, hydraulic and hydroelectric engineering technical field.By experimental section, experimental model, high-speed camera, synchronous trigger switch, laser doppler vibrometer, data collecting instrument, data handling system/computer and display and light source form.The present invention generates rising edge voltage signal by a kind of synchronous trigger switch, trigger signal is controlled using voltage signal, the signal acquisition for quantitatively accurately controlling high-speed camera and laser doppler vibrometer starts order, realize that unsteady cavitating flow and the quantitative precise synchronization of structure field measure, and the data of multiple physical field synchronous acquisition are pre-processed based on data handling system, time-domain analysis, frequency-domain analysis and time frequency analysis, is provided for further investigation fluid structurecoupling characteristic and reliably analyzes experimental data.
Description
Technical field
The present invention relates to a kind of water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration, belong to ship with
Submarine navigation device engineering, hydraulic and hydroelectric engineering technical field.
Background technology
Cavitation is that liquid internal local pressure drops to a kind of phase transition phenomena occurred during hold-up vapour pressure, cavitation
A series of problems, such as frequently can lead to vibration, the noise of body structure surface destruction, system effectiveness decline and structure.Wherein,
Unsteady cavitation flow induced vibration is related to multiple national defense industry field faces such as underawater ordnance, underwater emission, aerospace
Key technical issues.Coupling effect of seepage rock deformation under complicated water-power environment can cause system dynamic characteristic to substantially change, and with
The change tight association of the flow parameters such as flow velocity, pressure, tubulence energy, whirlpool rapids viscosity, different with change of flow state, this is significantly exacerbated
The research difficulty of flow induced vibration problem.
Domestic and foreign scholars have carried out substantial amounts of reality to cavitation flow induced vibration characteristic and its influence factor that object is streamed in water
Test research work.Wherein, schlieren method, holography and high speed video process mainly are used for cavitating flow form, research
Deng；For vibration characteristics, research mainly utilizes acceleration transducer, laser doppler vibrometer etc..But at present to sky
The research work for changing flow induced vibration is for single flow field structure, the observation of hole form or single structure field vibration speed mostly
Degree, the measurement of amplitude, lack the understanding to interaction relationship between synchronization flow field and structure field, it is difficult to unsteady sky
Multi- scenarios method Complex Phenomena in Vertical Bell Jar during change flow induced vibration is comprehensively studied.
The content of the invention
It can not be obtained at the same time the purpose of the present invention is to solve existing use single-measurement equipment experimental method unsteady
Transient flow field form and the problem of the vibration characteristics of structure field in cavitation flow induced vibration phenomenon, a kind of water tunnel experiment disclosed by the invention
With the more field synchronization measuring systems of unsteady cavitation flow induced vibration.
The purpose of the present invention is what is be achieved through the following technical solutions：
A kind of water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration, including：Experimental section, experiment mould
Type, high-speed camera, synchronous trigger switch, laser doppler vibrometer, data collecting instrument, data handling system/computer with
Display and light source.
Experimental section is transparent rectangular parallelepiped structure, installed in the contraction section and diffuser of circulating cavitation water tunnel experiment platform
Between, water (flow) direction is to flow to diffuser by contraction section；Experimental model includes hydrofoil part and support section, wherein hydrofoil part
In being placed in, for support section in the outside of experimental section, experimental model and the water (flow) direction in experimental section are perpendicular, and are put down positioned at place
The center in face；High-speed camera is placed in the hydrofoil part side of experimental model, for gathering experimental model region
Evolution of flow field situation；Light source provides illumination along high-speed camera equidirectional and vertical direction to experimental model；Laser-Doppler is surveyed
Vibration Meter is placed in the underface of experimental model, for gathering the vibration velocity of experimental model；Synchronous trigger switch is at the same time with taking the photograph at a high speed
Camera is connected with laser doppler vibrometer；Data collecting instrument is connected with laser doppler vibrometer, more for gathering laser
The general vibration data for strangling vialog；Computer is connected with data collecting instrument and high-speed camera at the same time, collects by high-speed camera
The data measured with laser doppler vibrometer, at the same based on the data handling system on computer to experimental data at
Reason.
Synchronous trigger switch includes switch and surge restraint circuit.
The synchronization trigger switch, when it is closed, necessarily upper will be produced by producing the controller of monophasic waveform voltage signal
Rise along voltage signal.When the voltage signal is higher than given threshold value, will produce specific electric wave signal and by cable transmission so as to
Trigger the high-speed camera and laser doppler vibrometer being attached thereto.
The high-speed camera has the characteristics that image fast recording, instant playback, image are visual and clear.
The laser doppler vibrometer is a kind of dynamic Laser interferometer based on optical Doppler effect, it is substantially former
Reason is the laser beam by launching certain frequency, and contrasts the laser beam frequency reflected through body structure surface measuring point, utilizes Doppler
The vibration velocity of calculation of effect body structure surface measuring point.
Work based on a kind of water tunnel experiment disclosed by the invention with the more field synchronization measuring systems of unsteady cavitation flow induced vibration
It is as method：
Step 1, flow parameter is adjusted, makes to produce Cavitation flows around experimental model in circulating cavitation water tunnel experiment platform experimental section
It is dynamic；
Step 2, determine the accurate measurement position of high-speed camera and laser doppler vibrometer, measurement parameter is set, if
Install standby triggering mode to trigger for rising edge, make high-speed camera and laser doppler vibrometer be in waiting triggering state；
Step 3, rising edge voltage signal is produced by synchronous trigger switch, how general synchronous triggering high-speed camera and laser be
Vialog is strangled, whole flow field is shown that measurement result and structural vibration measurement data are synchronously stored to computer；
Step 4, the data of multiple physical field synchronous acquisition are handled and analyzed based on data handling system, including pre- place
Reason, time-domain analysis, frequency-domain analysis and time frequency analysis, obtain flow location form and the synchronous evolution process of structural vibration speed, realize
Flow field and structure field multiple physical field synchro measure and data collection and analysis.
Beneficial effect
1st, a kind of unsteady more field synchronization measuring systems of cavitation flow induced vibration of the invention, are opened using a kind of synchronous triggering
Close, can the signal acquisition of synchronization implementation high-speed camera and laser doppler vibrometer start order, realize unsteady Cavitation flows
The quantitative precise synchronization of field and structure field measures.
2nd, a kind of unsteady more field synchronization measuring systems of cavitation flow induced vibration of the invention, can obtain flow location form and structure
One-to-one relationship in vibration velocity synchronization evolution process, realizes the Synchronization Analysis of hydrodynamic characterisitic and vibration characteristics,
Lay the foundation for further investigation fluid structurecoupling characteristic.
3rd, a kind of unsteady more field synchronization measuring systems of cavitation flow induced vibration of the invention, save space, cheap, can
Different experiments test equipment is flexibly replaced, is studied suitable for small tests such as water tunnel experiments.
Brief description of the drawings
Fig. 1 is a kind of unsteady more field synchronization measuring system schematic perspective views of cavitation flow induced vibration of the present invention；
Fig. 2 is circulating cavitation water tunnel experiment platform schematic diagram；
Fig. 3 is that whole flow field shows measuring system schematic diagram；
Fig. 4 is synchronous trigger switch surge restraint circuit figure；
Fig. 5 is a kind of operating process of the unsteady more field synchronization measuring systems of cavitation flow induced vibration of the present invention.
Wherein, how general 1-experimental section, 2-experimental model, 3-high-speed camera, 4-synchronization trigger switch, 5-laser is
Strangle vialog, 6-data collecting instrument, 7-computer, 8-pressurized tank, 9-vacuum pump, 10-pressure controller, 11-vacuum
Meter, 12-guide-ring, 13-rectifier, 14-contraction section, 15-diffuser, 16-return pipe, 17-water tank, 18-into
Water pipe, 19-motor, 20-axial-flow pump, 21-storage cistern, 22-light source, the input of 23-direct current, 24-fuse, 25-R1 electricity
Resistance, 26-R2 resistance, 27-C1 capacitances, 28-diode, 29-triode, 30-R3 resistance, 31-R4 resistance, 32-C2 electricity
Hold, 33-C3 capacitances.
Embodiment
The present invention is described in detail with embodiment below in conjunction with the accompanying drawings.
Embodiment 1
A kind of water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration, including：Experimental section 1, experiment mould
Type 2, high-speed camera 3, synchronous trigger switch 4, laser doppler vibrometer 5, data collecting instrument 6, data handling system/calculating
Machine and display 7 and light source 22, as shown in Figure 1.
The experimental section 1 is transparent rectangular parallelepiped structure, long 700mm, wide 70mm, high 190mm, installed in circulating cavitation
Between the contraction section 14 and diffuser 15 of water tunnel experiment platform, water (flow) direction is to flow to expansion segment 15 by contraction section 14；
The circulating cavitation water tunnel experiment platform mainly includes water inlet pipe 18, contraction section 14, experimental section 1, diffuser 15
Formed with return pipe 16, as shown in Figure 2.
Rectifier 13 and guide-ring 12 are equipped with experimental section upstream line, to reduce the large eddies knot of circulating water flow
Structure and turbulivity.Experimental section upstream line is connected with a large-scale water tank 17.Water storage tank volume is 11m3, in separated flow
Free property bubble, reduce turbulivity.The top of water tank 17 is connected with pressure controller 10 and vacuum pump 9 successively, while water storage
Tank top is also connected with pressurized tank 8, the water storage pressure inside the tank identical with pipeline is measured by vacuum meter 11, by by pressurized tank 8
Gas supply mode is carried out to water tank 17, adjusts liquid overhead gas content in water tank 17 so that in control loop pipeline
Pressure.
By the water sufficient standing in storage cistern 21 before experiment, so as to ensure that air content and cavitation nucleon are distributed basic in water
Stablize.Initial period is tested, the water in storage cistern 21 is filled with water tank 17, closes water supply valve；In experimentation, experiment porch
Interior current drive axial-flow pump 20 to realize water circulation by the motor 19 of power 55KW, rated speed 1480rpm, loop direction be into
15-return pipe of water pipe 18-water tank, 17-contraction section, 14-experimental section, 1-diffuser 16.
The experimental model 2 is NACA series hydrofoils, including hydrofoil part and support section, wherein hydrofoil are partially disposed in reality
Test in section 1, water (flow) direction of the support section in the outside of experimental section 1, with experimental section 1 is perpendicular, and experimental model 2 is located at institute
In the center of plane.
The high-speed camera 3 is placed in the outside of experimental section 1 close to the side of 2 hydrofoil part of experimental model, for gathering reality
Test the evolution of flow field situation of 2 region of model；High-speed camera stand bottom is double using rubber vibration insulating pad and sponge vibration isolator
Weight vibration isolation measure.
The light source 22 is located at 1 leading flank of experimental section and upper surface respectively, and wherein experimental section leading flank refers to outside experimental section 1
Close to the side of 2 hydrofoil end of experimental model, upper surface refers to the outside of experimental section 1 close to the side of the upper surface of experimental model 2.
The laser doppler vibrometer 5 is placed in the underface of experimental model 2, for gathering the vibration speed of experimental model 2
Degree.
The data collecting instrument 6 is connected with laser doppler vibrometer 5, is surveyed for gathering laser doppler vibrometer 5
The vibration data obtained.
The synchronization trigger switch 4 includes switch and surge restraint circuit.Its operation principle is as shown in Figure 4.When normal work
When making, R1 resistance 25,26 resistance value of R2 resistance are identical, therefore R1 resistance 25, the voltage at 26 both ends of R2 resistance are identical, in diode 28
Under effect, the electric current in circuit is without flow through R3 resistance 30, then triode 29 turns at this time, and triode 29 is equivalent to one section at this time
Conducting wire, output signal are equal to input direct voltage.And when circuit produces surge voltage due to break-make, R1 resistance 25, R2 electricity
The voltage rise at 26 both ends is hindered, but due to the clamping action of diode 28, then when the voltage and normal work at 25 end of resistance
It is identical, then the voltage at 26 end of R2 resistance will rise, and 26 voltage of R2 resistance rises, and R3 resistance 30 turns on, and electric current flows through R3 at this time
Resistance 30, R4 resistance 31, then triode 29 be no longer turned on, temporarily disconnected at triode 29 equivalent to circuit, play guarantor
Shield acts on, and when surge voltage declines, circuit recovers to normal operating conditions.C1 capacitances 27, C2 capacitances 32 and C3 capacitances 33 exist
Play the role of storing electric field energy in alternating current circuit.
The synchronization trigger switch 4 is connected with high-speed camera 3 and laser doppler vibrometer 5 at the same time；When it is closed,
Certain rising edge voltage signal will be produced by producing the controller of monophasic waveform voltage signal.When the voltage signal is higher than given threshold value
When (1000mV), specific electric wave signal will be produced and by cable transmission so as to trigger the high-speed camera 3 being attached thereto and swash
Light Doppler vibrometer 5, high-speed camera 3, laser doppler vibrometer 5 and data collecting instrument 6 according to respective frequency acquisition into
Row data acquisition, and by gathered data synchronous transfer to computer, using data collecting system 7 carry out data synchronization processing with point
Analysis.
The computer 7 is connected with data collecting instrument 6 and high-speed camera 3 at the same time, collects by high-speed camera 3 and laser
The data that Doppler vibrometer 5 measures；Experimental data is handled based on data handling system 7, including data prediction, when
Domain analysis, frequency-domain analysis and time frequency analysis.
The data prediction is to be removed trend term and denoising for the structural vibration speed data measured.Its
In, it is to remove the null offset produced with temperature due to foundation motion, the signal amplifier of test equipment, sense to remove trend term
Deviate baseline amount caused by environmental disturbances around device etc..Assuming that n-order polynomial：
Wherein, piFor multinomial coefficient.According to principle of least square fitted trend item multinomial, multinomial coefficient is tried to achieve,
So as to fulfill removal trend term.Denoising is for the denoising for using wavelet analysis to carry out signal in test data, head
Wavelet decomposition first is carried out to signal, then wavelet coefficient is handled in the form of threshold value etc., filters interference signal source, most
Signal is reconstructed afterwards, is obtained without glitch-free signal message of making an uproar.
The time-domain analysis is to establish the data sequence that flow location form picture is changed over time with structural vibration speed, wherein
Vibration velocity signal uses analog signal output, and the conversion relation for exporting signal and vibration velocity is：
U=kua (2)
Wherein, u is vibration velocity (mm/s), and k is analog signal conversion coefficient, ua(mm/s/V) is exported for original signal.
The frequency-domain analysis is to establish the frequency sequence that flow location form is developed with structural vibration speed period, in a frequency domain
Stream field form carries out regular description with structural vibration speed.For flow location form evolution process, extraction flow field cavitation development
In the cycle, calculate the large scale vacuole group's shedding frequence and the unsteady shedding frequence of flow field spiral structure of cavitation evolution.For
Vibration velocity data carry out Fourier transform, discrete signal xnFourier transform calculation formula it is as follows：
The Hanning window function recommended using IEC codes carries out truncated error processing, its calculation formula is as follows：
Frequency-domain analysis the result is that carrying out regular description to structural vibration speed in a frequency domain.
The time frequency analysis is to be based on continuous wavelet transform and short time discrete Fourier transform, establishes flow location form picture and structure
Vibration frequency with the time synchronous development law.
The course of work is as shown in Figure 5：
A. it is 5m/s to adjust circulating cavitation water tunnel experiment platform experimental section ingress flow rate, and pressure 13169Pa, makes experiment
In section cavitating flows are produced around experimental model；
B. start whole flow field and show measuring system (as shown in Figure 3) and structural vibration measuring system；
C., control parameter is set, i.e. the frequency acquisition of high-speed camera 3 and acquisition time length is respectively fs1=20kHz and
T1The frequency acquisition and acquisition time length of=30s, laser doppler vibrometer 5 and data collecting instrument 6 are respectively fs2=22kHz
And T2=30s；
D. unify triggering mode to trigger for rising edge, whole flow field is shown that measuring system and structural vibration measuring system are located
In wait triggering state；
E. rising edge voltage signal is generated by synchronous trigger switch 4, the synchronous whole flow field that triggers shows measuring system and knot
Structure Vibration-Measuring System；
F. whole flow field is shown that measuring system and the data of structural vibration measuring system collection are stored in same computer at the same time
In host 7；
G. vibration velocity test data is pre-processed using data handling system, based on original test data sequence
uoriginal(t), according to principle of least square fitted trend item multinomial utrend(t), original test number is determined using wavelet analysis
According to noise contribution be unoise(t), it is by pretreated vibration velocity test data：
ua(t)=uoriginal(t)-utrend(t)-unoise(t) (5)
H. stream field and structure field test data synchronize time-domain analysis, establish flow location form picture and structural vibration speed
Spend the data sequence changed over time.Extraction flow field in cavity length/equivalent area/volume change with time trend l (t)/
Area (t)/volume (t), by pretreated vibration velocity analog signal be converted to digital signal can obtain vibration velocity when
Between sequence be：
U (t)=kua(t) (6)
K is analog signal conversion coefficient.The synchronization of experimental data time series is carried out based on the identical actual physics moment
Analysis, the i.e. corresponding flow location forms of any time t and the t/f that structural vibration data are respectively high-speed camera record datas1
The t/f of frame and laser doppler vibrometer gathered datas2Frame, wherein fs1And fs2How general respectively high-speed camera and laser be
The sample frequency of vialog is strangled, it is achieved thereby that vibration velocity is corresponded with flow location form temporal evolution process, ensure that same
The real effectiveness of step data；
I. stream field and structure field test data synchronize frequency-domain analysis, based on Fourier transformation extraction structural vibration frequency
Rate distribution U (f), while flow field cavitation lead-time T is calculated based on the extraction of flow location form evolution process, calculate cavitation evolution
Large scale vacuole group shedding frequence and the unsteady shedding frequence of flow field spiral structure.By structural vibration frequency and flow field periodically
Evolution frequency compares and analyzes；
J. stream field and structure field test data synchronize time frequency analysis, establish flow location form picture and structural vibration frequency
Rate with the time synchronous development law.Using based on continuous wavelet transform and short time discrete Fourier transform, cavitation evolution is calculated
Large scale vacuole group shedding frequence, the unsteady shedding frequence of flow field spiral structure and structural vibration frequency with the time differentiation
Rule.
K. continue to measure if desired, repeat d-k steps；
L. complete to terminate to test after the above process.
It is merely illustrative of the technical solution of the present invention above, those of ordinary skill in the art can be to the technology of the present invention
Scheme technical scheme is modified or replaced equivalently.Make an amendment within the spirit and principles of the invention, equivalent substitution, improvement etc.,
It should all be included in the protection scope of the present invention.
Claims (7)
- A kind of 1. water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration, it is characterised in that：Including：Experimental section (1), experimental model (2), high-speed camera (3), synchronous trigger switch (4), laser doppler vibrometer (5), data collecting instrument (6), computer (7) and light source (22)；Experimental section (1) is transparent rectangular parallelepiped structure, contraction section (14) and expansion installed in circulating cavitation water tunnel experiment platform Between dissipating section (15), water (flow) direction is to flow to diffuser (15) by contraction section (14)；Experimental model (2) includes hydrofoil part and branch Support part point, the hydrofoil are partially disposed in (1), and the support section is in the outside of (1), experimental model (2) and experimental section (1) Water (flow) direction it is perpendicular, and (2) are located at the center of place plane；High-speed camera (3) is placed in the water of experimental model (2) Alar part side；Light source (22) provides illumination along high-speed camera equidirectional and vertical direction to experimental model (2)；How general laser is Strangle the underface that vialog (5) is placed in experimental model (2)；Synchronous trigger switch (4) while more with high-speed camera (3) and laser General Le vialog (5) is connected；Data collecting instrument (6) is connected with laser doppler vibrometer (5)；Computer (7) at the same with number It is connected according to Acquisition Instrument (6) with high-speed camera (3).
- 2. a kind of water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration as claimed in claim 1, it is special Sign is：The method of work of the system is：Step 1, flow parameter is adjusted, makes to produce cavitating flows around experimental model in circulating cavitation water tunnel experiment platform experimental section；Step 2, determine the accurate measurement position of high-speed camera and laser doppler vibrometer, measurement parameter is set, setting is set Standby triggering mode triggers for rising edge, makes high-speed camera and laser doppler vibrometer be in waiting triggering state；Step 3, rising edge voltage signal is produced by synchronous trigger switch, it is synchronous to trigger high-speed camera and laser-Doppler survey Vibration Meter, shows that measurement result and structural vibration measurement data are synchronously stored to computer by whole flow field；Step 4, the data of multiple physical field synchronous acquisition are handled and analyzed based on data handling system, including pretreatment, Time-domain analysis, frequency-domain analysis and time frequency analysis, obtain flow location form and the synchronous evolution process of structural vibration speed, realize stream Field and structure field multiple physical field synchro measure and data collection and analysis.
- 3. a kind of water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration as claimed in claim 1, it is special Sign is：The synchronization trigger switch (4) includes switch and surge restraint circuit；The surge restraint circuit includes：R1 resistance (25), R2 resistance (26), C1 capacitances (27), diode (28), triode (29), R3 resistance (30), R4 resistance (31), C2 capacitances (32) and C3 capacitances (33)；R1 resistance (25), R2 resistance (26) resistance value are identical, therefore R1 resistance (25), the voltage at R2 resistance (26) both ends are identical, two Under the action of pole pipe (28), the electric current in circuit is without flow through R3 resistance (30), then triode (29) turns at this time, at this time three pole Manage (29) and be equal to input direct voltage equivalent to a section lead, output signal；And when circuit produces surge voltage due to break-make When, the voltage rise of R1 resistance (25), R2 resistance (26) both ends, but due to the clamping action of diode (28), then resistance (25) identical when the voltage at end is with normal work, then the voltage at R2 resistance (26) end will rise, and R2 resistance (26) voltage rises, R3 Resistance (30) turns on, and electric current flows through R3 resistance (30), R4 resistance (31) at this time, and then triode (29) is no longer turned on, equivalent to Circuit temporarily disconnects at triode (29) place, plays protective effect, and when surge voltage declines, circuit recovers to working normally State；C1 capacitances (27), C2 capacitances (32) and C3 capacitances (33) play the role of storing electric field energy in alternating current circuit.
- 4. a kind of water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration as claimed in claim 2, it is special Sign is：Data prediction described in step 4 is to be removed for the structural vibration speed data measured at trend term and denoising Reason；Wherein, it is the zero point drift that removal is produced due to foundation motion, the signal amplifier of test equipment with temperature to remove trend term Deviate baseline amount caused by environmental disturbances around shifting, sensor etc.；Assuming that n-order polynomial：<mrow> <mi>X</mi> <mo>=</mo> <munderover> <mo>&Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>0</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>p</mi> <mi>i</mi> </msub> <msup> <mi>x</mi> <mi>i</mi> </msup> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow>Wherein, piFor multinomial coefficient；According to principle of least square fitted trend item multinomial, multinomial coefficient is tried to achieve, so that real Now remove trend term；Denoising is for the denoising for using wavelet analysis to carry out signal in test data, first to letter Number carry out wavelet decomposition, then wavelet coefficient is handled in the form of threshold value etc., filter interference signal source, finally to letter Number it is reconstructed, obtains without glitch-free signal message of making an uproar.
- 5. a kind of water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration as claimed in claim 2, it is special Sign is：The time-domain analysis is to establish the data sequence that flow location form picture is changed over time with structural vibration speed, wherein Vibration velocity signal uses analog signal output, and the conversion relation for exporting signal and vibration velocity is：U=kua (2)Wherein, u is vibration velocity (mm/s), and k is analog signal conversion coefficient, ua(mm/s/V) is exported for original signal.
- 6. a kind of water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration as claimed in claim 2, it is special Sign is：The frequency-domain analysis is to establish the frequency sequence that flow location form is developed with structural vibration speed period, in a frequency domain Stream field form carries out regular description with structural vibration speed；For flow location form evolution process, extraction flow field cavitation development In the cycle, calculate the large scale vacuole group's shedding frequence and the unsteady shedding frequence of flow field spiral structure of cavitation evolution；For Vibration velocity data carry out Fourier transform, discrete signal xnFourier transform calculation formula it is as follows：<mrow> <mi>X</mi> <mrow> <mo>(</mo> <mi>f</mi> <mo>,</mo> <mi>T</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>&Delta;</mi> <mi>t</mi> <munderover> <mo>&Sigma;</mo> <mrow> <mi>n</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>N</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <msub> <mi>x</mi> <mi>n</mi> </msub> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mi>i</mi> <mn>2</mn> <mi>&pi;</mi> <mi>f</mi> <mi>n</mi> <mi>&Delta;</mi> <mi>t</mi> </mrow> </msup> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>3</mn> <mo>)</mo> </mrow> </mrow>The Hanning window function recommended using IEC codes carries out truncated error processing, its calculation formula is as follows：<mrow> <mtable> <mtr> <mtd> <mrow> <mi>w</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mi>c</mi> <mi>o</mi> <mi>s</mi> <mo>(</mo> <mfrac> <mrow> <mn>2</mn> <mi>&pi;</mi> <mi>t</mi> </mrow> <mi>T</mi> </mfrac> <mo>)</mo> <mo>)</mo> </mrow> </mrow> </mtd> <mtd> <mrow> <mn>0</mn> <mo>&le;</mo> <mi>t</mi> <mo>&le;</mo> <mi>T</mi> </mrow> </mtd> </mtr> </mtable> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>4</mn> <mo>)</mo> </mrow> </mrow>Frequency-domain analysis the result is that carrying out regular description to structural vibration speed in a frequency domain.
- 7. a kind of water tunnel experiment more field synchronization measuring systems of unsteady cavitation flow induced vibration as claimed in claim 2, it is special Sign is：The time frequency analysis is to be based on continuous wavelet transform and short time discrete Fourier transform, establishes flow location form picture and structure Vibration frequency with the time synchronous development law.
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Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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| CN108801588A (en) * | 2018-05-30 | 2018-11-13 | 上海理工大学 | Hydraulic interior flow field characteristic quantity visualizes frequency-domain analysis method |
| CN108898139A (en) * | 2018-06-04 | 2018-11-27 | 上海大学 | Laser radar data anti-interference processing method and its experimental provision under a kind of rainy environment |
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| CN109523537A (en) * | 2018-11-20 | 2019-03-26 | 北京理工大学 | A kind of unsteady cavitating flows fine structure analysis method based on image procossing |
| CN110842349A (en) * | 2019-08-02 | 2020-02-28 | 江苏大学 | Device and method for removing burrs based on laser cavitation |
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| CN110907131A (en) * | 2019-12-09 | 2020-03-24 | 中国科学院力学研究所 | Free-launch hydrofoil experimental device |
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| CN113295377A (en) * | 2021-05-12 | 2021-08-24 | 上海机电工程研究所 | Non-linear shaking test method and system based on analytic mode decomposition |
| CN113358312A (en) * | 2021-06-04 | 2021-09-07 | 北京理工大学 | Vortex-induced vibration synchronous measurement method based on high-speed cavitation water tunnel |
| CN113390452A (en) * | 2021-06-16 | 2021-09-14 | 北京康斯特仪表科技股份有限公司 | Method and device for calibrating switch type instrument |
| WO2022126684A1 (en) * | 2020-12-14 | 2022-06-23 | 深圳大学 | Laser doppler vibrometer-based image vibration measurement system |
| CN114813037A (en) * | 2022-04-21 | 2022-07-29 | 中国船舶科学研究中心 | Method for analyzing frequency distribution characteristics of cavitation flow structure |
| CN117405354A (en) * | 2023-12-13 | 2024-01-16 | 中国人民解放军海军工程大学 | Flow excitation resonance suppression method for cavitation water hole corner segment guide vane |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108645757A (en) * | 2018-05-03 | 2018-10-12 | 华中科技大学 | A kind of device and method measuring super hydrophobic surface effective slip length |
| CN108645757B (en) * | 2018-05-03 | 2019-12-24 | 华中科技大学 | Device and method for measuring effective sliding length of super-hydrophobic surface |
| CN108801588A (en) * | 2018-05-30 | 2018-11-13 | 上海理工大学 | Hydraulic interior flow field characteristic quantity visualizes frequency-domain analysis method |
| CN108801588B (en) * | 2018-05-30 | 2019-12-03 | 上海理工大学 | Hydraulic interior flow field characteristic quantity visualizes frequency-domain analysis method |
| CN108898139A (en) * | 2018-06-04 | 2018-11-27 | 上海大学 | Laser radar data anti-interference processing method and its experimental provision under a kind of rainy environment |
| CN109238638A (en) * | 2018-08-07 | 2019-01-18 | 天津大学 | A kind of novel water hole experimental system for simulating true marine environment |
| CN109523537A (en) * | 2018-11-20 | 2019-03-26 | 北京理工大学 | A kind of unsteady cavitating flows fine structure analysis method based on image procossing |
| CN110842349A (en) * | 2019-08-02 | 2020-02-28 | 江苏大学 | Device and method for removing burrs based on laser cavitation |
| CN110907107B (en) * | 2019-11-07 | 2021-04-20 | 北京动力机械研究所 | Micro-tube bundle type precooler diaphragm vibration measurement system and method |
| CN110907107A (en) * | 2019-11-07 | 2020-03-24 | 北京动力机械研究所 | Micro-tube bundle type precooler diaphragm vibration measurement system and method |
| CN110907131A (en) * | 2019-12-09 | 2020-03-24 | 中国科学院力学研究所 | Free-launch hydrofoil experimental device |
| CN111397522A (en) * | 2020-04-07 | 2020-07-10 | 北京理工大学 | Method for measuring two-dimensional transient bending and torsional deformation of structure for water tunnel experiment |
| CN111397522B (en) * | 2020-04-07 | 2021-05-04 | 北京理工大学 | Method for measuring two-dimensional transient bending and torsional deformation of structure for water tunnel experiment |
| CN112539915A (en) * | 2020-11-27 | 2021-03-23 | 中国运载火箭技术研究院 | Dynamic display system and method for stress waves in underwater vehicle structure |
| CN112539915B (en) * | 2020-11-27 | 2023-03-07 | 中国运载火箭技术研究院 | Dynamic display system and method for stress waves in underwater vehicle structure |
| WO2022126684A1 (en) * | 2020-12-14 | 2022-06-23 | 深圳大学 | Laser doppler vibrometer-based image vibration measurement system |
| CN112903240B (en) * | 2021-01-14 | 2022-10-28 | 太原理工大学 | Visual observation device for excitation induced cavitation |
| CN112903240A (en) * | 2021-01-14 | 2021-06-04 | 太原理工大学 | Visual observation device for excitation induced cavitation |
| CN112924138A (en) * | 2021-01-27 | 2021-06-08 | 西北工业大学 | Multifunctional bionic hydrodynamic test platform |
| CN112924138B (en) * | 2021-01-27 | 2023-03-10 | 西北工业大学 | Multifunctional bionic hydrodynamic test platform |
| CN113295377A (en) * | 2021-05-12 | 2021-08-24 | 上海机电工程研究所 | Non-linear shaking test method and system based on analytic mode decomposition |
| CN113358312A (en) * | 2021-06-04 | 2021-09-07 | 北京理工大学 | Vortex-induced vibration synchronous measurement method based on high-speed cavitation water tunnel |
| CN113390452A (en) * | 2021-06-16 | 2021-09-14 | 北京康斯特仪表科技股份有限公司 | Method and device for calibrating switch type instrument |
| CN113390452B (en) * | 2021-06-16 | 2023-08-18 | 北京康斯特仪表科技股份有限公司 | Method and device for calibrating switch type instrument |
| CN114813037A (en) * | 2022-04-21 | 2022-07-29 | 中国船舶科学研究中心 | Method for analyzing frequency distribution characteristics of cavitation flow structure |
| CN117405354A (en) * | 2023-12-13 | 2024-01-16 | 中国人民解放军海军工程大学 | Flow excitation resonance suppression method for cavitation water hole corner segment guide vane |
| CN117405354B (en) * | 2023-12-13 | 2024-02-23 | 中国人民解放军海军工程大学 | Flow excitation resonance suppression method for cavitation water hole corner segment guide vane |
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