Complex building surface piezometric pipeline signal distortion correction method in wind tunnel test

Abstract

The invention relates to a complex building surface piezometric pipeline signal distortion correction method in a wind tunnel test, and relates to the field of wind tunnel test data processing. The method comprises the following steps: S1, preparing a building model, dividing areas, and setting measuring points; s2, measuring the pipe diameter of the piezometric pipe at the measuring point of the wind tunnel test; s3, performing a wind tunnel test, and processing a result to obtain a wind pressure time history; s4, filtering the wind pressure time history; and S5, correcting the distorted piezometric pipeline signal to obtain a real signal time history. According to the method, through two times of filtering, the problem of pipeline distortion occurring during pressure measurement can be accurately corrected, and the method is suitable for areas with large complex building deformation. Moreover, the method can effectively improve the accuracy of data measured by the wind tunnel test, and better assists the development of production and scientific research. The problems that only the characteristics of the piezometric tube are considered in an existing method, the correction method is simple, and wrong correction results are easily generated are solved.

Description

Technical Field

[0001] The invention relates to a method for correcting signal distortion of a pressure measuring pipeline on a complex building surface in a wind tunnel test, and relates to the field of wind tunnel test data processing. Background Art

[0002] Wind tunnel test is one of the main ways to study the wind pressure on the surface of complex building structures, and the pressure tube is one of the main tools for measuring wind pressure. However, since the signal will be significantly distorted after passing through the pipeline system, the distortion of the pipeline signal will affect the average wind pressure, pulsating wind pressure, energy spectrum, spatial correlation, non-Gaussian characteristics, etc. on the building surface, making it impossible to accurately measure the wind pressure on the building surface.

[0003] Due to the changeable shape of complex buildings, the number of pressure measuring holes is more than that of conventional buildings. At the same time, the flow field will show violent flow separation at the large deformation of complex buildings. At this time, the pipe distortion will amplify or reduce the wind pressure change here. The pipe distortion at the large deformation is different from that at the small deformation. Therefore, it is necessary to adopt special distortion correction methods at the complex deformation.

[0004] The existing method is to correct the distortion by using the fluid pipeline dissipation model theory. The existing method only considers the characteristics of the pressure measuring tube itself, and the correction method is simple, which is easy to produce wrong correction results. In addition, all measuring points are corrected by the same method, which is easy to cause wrong correction results. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the existing method only considers the characteristics of the pressure measuring tube itself, and the correction method is simple and easily produces erroneous correction results.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a method for correcting signal distortion of a pressure measuring pipeline on a complex building surface in a wind tunnel test, comprising the following steps:

[0007] S1. Make a building model, divide the area, and set measurement points;

[0008] S2. Determine the diameter of the pressure measuring tube at the measuring point of the wind tunnel test;

[0009] S3, conduct a wind tunnel test and process the results to obtain a wind pressure time history;

[0010] S4, filtering the wind pressure time history;

[0011] S5. Correct the distorted pressure measuring pipeline signal to obtain the real signal time history.

[0012] Among them, the area of ​​a single area in step S1 of the above method accounts for between 1% and 5% of the total surface area of ​​the building, and the division principle can refer to the division principle of the building surface shape coefficient, wherein the area with larger deformation is divided into Class II, and the area with smaller deformation is divided into Class I.

[0013] Wherein, in step S2 of the above method, a laser measurement method is used to measure the inner radius of the pressure measuring tube.

[0014] Among them, in step S2 of the above method, the water injection method is used to determine the internal radius of the pressure measuring tube, and the water injection method includes the following steps: a. Select a pressure measuring tube with a length of L and put it into a dryer for drying, and use a test balance to measure its mass as m1; b. Then immerse the pressure measuring tube in water so that the tube is full of water, then take out and wipe the water on the outer wall, and measure its weight again as m2; c. Calculate the internal radius of the pressure measuring tube as: Where ρ is the air density.

[0015] Furthermore, in the above method, at least 5 piezometers are randomly selected from the piezometer sample to measure the apertures, and the average of the five groups of aperture numbers is taken to obtain the inner radius of the experimental piezometer.

[0016] In the above method, in step S3, a wind tunnel test is performed to obtain a test result, which is a time history of a bunch of electrical signals, which needs to be processed to obtain a wind pressure time history, and the formula used is: C pi (t) is the pressure coefficient at measuring point i at time t, P i (t) is the pressure acting on the measuring point i, P0 and P ∞ Respectively represent the total pressure and static pressure at the reference height.

[0017] In the above method, in step S4, an integer n is selected as the size of the filter segment. When the amount of wind pressure time series data is less than 15,000, n=4; when the amount of wind pressure time series data is greater than or equal to 15,000, n=5; for each position t in the time series, the weighted values ​​of n consecutive data points from t-n+1 to t are calculated; the weighted values ​​are shown in the following table:

[0018] When n=4,

[0019]

[0020] When n=5,

[0021]

[0022] And when t=1,2,3,4,

[0023] C pi,move (t) = C pi (t).

[0025] Furthermore, the average value obtained in the above method becomes the value of the new time series at position t. After the calculation is completed once, the filter segment is moved forward by one data point and the above calculation is repeated until the entire time series is covered.

[0026] Furthermore, in step S5 of the above method, a theoretical frequency response function is introduced to correct the distorted pressure measurement pipeline signal. The solution formula of the theoretical frequency response function H(w) is:

[0027] Category I:

[0028]

[0029] Category II:

[0030]

[0031] Where: V t =πR 2 L(m 3 ) is the internal volume of the pressure tube, L is the length of the pressure tube (m), R is the internal radius of the pressure tube (m); V is the internal cavity volume of the pressure sensor (m 3 );

[0032] σ is the dimensionless increment of the pressure sensor cavity deformation;

[0033] k is the internal air variation factor associated with the pressure sensor cavity (dimensionless);

[0034] γ is the specific heat ratio of air at the test temperature T0 (K) and pressure P0 (Pa);

[0035] c=(γP0 / ρ s ) 1 / 2 is the speed of sound (m / s), ρ s is the air density under test conditions (kg / m 3 );

[0036] i=(-1) 1 / 2 ;P r =μC p / λ is the air Prandtl number (dimensionless), μ is the dynamic viscosity (Pa·s), C p is the specific heat capacity (J·kg -1 ·K -1 ), λ is the thermal conductivity (W·m -1 ·K -1 );

[0037] J0 and J2 are the first-kind Bessel functions of the zeroth and second orders, respectively;

[0038] sinh and cosh are the hyperbolic sine and cosine functions respectively;

[0039] w=2πf is the circular frequency.

[0040] Furthermore, in step S5 of the above method, the distorted pressure measurement pipeline signal is corrected by the theoretical frequency response function to obtain the real signal time course C p0 (t), the conversion formula is:

[0041]

[0042] Where real represents the real part of the complex number, FFT is the fast Fourier transform, and IFFT is the inverse fast Fourier transform.

[0043] The beneficial effect of the present invention is that the method can more accurately correct the pipeline distortion problem that occurs during pressure measurement by filtering twice, and at the same time propose a corresponding correction method for areas with large deformation of complex buildings. The method can effectively improve the accuracy of data measured in wind tunnel tests and better assist in the development of production and scientific research. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic diagram of the original wind pressure time series.

[0045] Figure 2 This is a schematic diagram of the wind pressure time history after correction according to the present invention.

[0046] Figure 3 It is a schematic diagram comparing the wind pressure time history of the present invention and the original one.

[0047] Figure 4 It is a schematic diagram of the building model structure of the present invention.

[0048] Figure 5 It is a schematic diagram of the partitioning of the building model of the present invention.

[0049] Figure 6 It is a schematic diagram of the arrangement of measuring points on the building surface of the building model of the present invention. DETAILED DESCRIPTION

[0050] The present invention is further described below in conjunction with embodiments and drawings.

[0051] like Figures 1 to 6 As shown, the method for correcting signal distortion of a pressure measuring pipeline on a complex building surface in a wind tunnel test of the present invention comprises the following steps:

[0052] S1. Make a building model, divide the area, and set measurement points;

[0053] S2. Determine the diameter of the pressure measuring tube at the measuring point of the wind tunnel test;

[0054] S3, conduct a wind tunnel test and process the results to obtain a wind pressure time history;

[0055] S4, filtering the wind pressure time history;

[0056] S5. Correct the distorted pressure measuring pipeline signal to obtain the real signal time history. It is understood by those skilled in the art that the wind tunnel pressure test is a common method for studying the aerodynamic characteristics of the model. During the test, a certain length of pressure measuring tube is required to connect the pressure measuring hole on the surface of the model with the pressure sensor. Therefore, the measured pressure signal is not the real pressure on the surface of the model, but a distorted signal after the interference of the pressure measuring tube. The difference between the distorted signal and the real signal is mainly manifested in two aspects: (1) the signal energy (amplitude) is amplified or weakened; (2) the signal phase lags. And this difference will increase with the increase of the length of the pressure measuring tube. In some large-scale pressure measuring tests, the length of the pressure measuring tube has reached more than 2 meters, and the wind pressure signal will be seriously distorted. For the pressure measuring test, the measured wind pressure signal is almost the basis for all subsequent data analysis, such as: obtaining the wind pressure coefficient, static three-force coefficient, buffeting force spectrum, coherence function, etc. of the model. Therefore, before conducting a model wind tunnel pressure test, it is necessary to first conduct a detailed study on the signal distortion of the pressure measuring pipeline and think about how to correct the distorted signal more accurately. In step S1, the model to be studied is prepared and the area is divided. The building surface is divided into multiple areas. The number of divisions can be several or dozens, depending on the actual complexity of the building. Since the diameters of pressure measuring tubes of the same specification but different batches may also be different, the radius of the pressure measuring tubes of the batch must be measured, so step S2 uses on-site measurement to estimate the diameters of the pressure measuring tubes of the same batch. Step S3 conducts a wind tunnel test to obtain the test results, which are a bunch of electrical signal time series, which need to be processed to obtain the wind pressure time series. Step S4 performs the first filtering on the wind pressure time series. Step S5 introduces the theoretical frequency response function to correct the distorted pressure measuring pipeline signal to obtain the real signal time series.

[0057] Preferably, the area of ​​a single area in step S1 of the above method accounts for 1% to 5% of the total surface area of ​​the building, and the division principle can refer to the division principle of the building surface body coefficient, where the area with larger deformation is divided into Class II, and the area with smaller deformation is divided into Class I. It can be understood by those skilled in the art that the present invention actually prefers that the area of ​​a single area accounts for 5% to 1% of the total surface area of ​​the building, that is, the number of divided areas is between 20 and 100, which can well balance the calculation accuracy and efficiency. The division principle can refer to the division principle of the building surface body coefficient, where the area with larger deformation is divided into Class II, and the area with smaller deformation is divided into Class I.

[0058] Preferably, in step S2 of the above method, the inner radius of the pressure tube is measured by laser measurement. Those skilled in the art will appreciate that, in order to ensure the accuracy of the data, the method uses the laser measurement method to measure the inner radius of the pressure tube, and the laser measurement method is a prior art.

[0059] Preferably, in step S2 of the above method, the inner radius of the pressure measuring tube is determined by a water injection method, and the water injection method comprises the steps of: a. selecting a pressure measuring tube of length L and placing it in a dryer for drying, and using a test balance to measure its mass as m1; b. immersing the pressure measuring tube in water so that the tube is filled with water, then taking out and wiping the water on the outer wall, and measuring its weight again as m2; c. calculating the inner radius of the pressure measuring tube as: Where ρ is the air density. It can be understood by those skilled in the art that in order to ensure the internal radius data of the pressure measuring tube, this method adopts the water injection method for measurement, specifically through the steps a, select a pressure measuring tube with a length of L and put it into a dryer for drying, and use a test balance to measure its mass as m1; b, then immerse the pressure measuring tube in water so that the tube is full of water, then take out and wipe the water on the outer wall, and measure its weight again as m2; c, calculate the internal radius of the pressure measuring tube as: Where ρ is the air density.

[0060] Preferably, in the above method, at least 5 piezometers are randomly selected from the piezometer sample for aperture measurement, and the five groups of aperture numbers are averaged to obtain the internal radius of the experimental piezometer. It can be understood by those skilled in the art that, in order to ensure the accuracy of the calculated data, considering that the diameters of piezometers of the same specification but different batches may also be different, at least 5 piezometers are actually randomly selected from the piezometer sample for aperture measurement, and the five groups of aperture numbers are averaged to obtain the internal radius of the experimental piezometer.

[0061] Preferably, in step S3 of the above method, a wind tunnel test is performed to obtain a test result, which is a stack of electrical signal time histories, which need to be processed to obtain a wind pressure time histories, and the formula used is: C pi (t) is the pressure coefficient at measuring point i at time t, P i (t) is the pressure acting on the measuring point i, P0 and P ∞ Respectively represent the total pressure and static pressure at the reference height. Those skilled in the art can understand that in order to obtain the wind pressure time history, the formula used in this method is: C pi (t) is the pressure coefficient at measuring point i at time t, P i (t) is the pressure acting on the measuring point i, P0 and P ∞ Respectively represent the total pressure and static pressure at the reference height.

[0062] Preferably, in step S4 of the above method, an integer n is selected as the size of the filter segment, when the amount of wind pressure time series data is less than 15,000, n=4; when the amount of wind pressure time series data is greater than or equal to 15,000, n=5; for each position t in the time series, the weighted values ​​of n consecutive data points from t-n+1 to t are calculated; the weighted values ​​are shown in the following table:

[0063] When n=4,

[0064]

[0065] When n=5,

[0066]

[0067] And when t=1,2,3,4,

[0068] C pi,move (t) = C pi (t). Those skilled in the art will appreciate that step S4 performs a first filtering on the wind pressure time history obtained in step S3, which is specifically derived from the above formula.

[0069] Preferably, the average value obtained in the above method becomes the value of the new time series at position t. After the calculation is completed once, the filter segment is moved forward by one data point, and the above calculation is repeated until the entire time series is covered. It can be understood by those skilled in the art that in order to ensure complete data coverage, the average value obtained by this method becomes the value of the new time series at position t. After the calculation is completed once, the filter segment is moved forward by one data point, and the above calculation is repeated until the entire time series is covered.

[0070] Preferably, in step S5 of the above method, a theoretical frequency response function is introduced to correct the distorted pressure measurement pipeline signal, and the solution formula of the theoretical frequency response function H(w) is:

[0071] Category I:

[0072]

[0073] Category II:

[0074]

[0075] Where: V t =πR 2 L(m 3 ) is the internal volume of the pressure tube, L is the length of the pressure tube (m), R is the internal radius of the pressure tube (m); V is the internal cavity volume of the pressure sensor (m 3 );

[0076] σ is the dimensionless increment of the pressure sensor cavity deformation;

[0077] k is the internal air variation factor associated with the pressure sensor cavity (dimensionless);

[0078] γ is the specific heat ratio of air at the test temperature T0 (K) and pressure P0 (Pa);

[0079] c=(γP0 / ρ s ) 1 / 2 is the speed of sound (m / s), ρ s is the air density under test conditions (kg / m 3 );

[0080] i=(-1) 1 / 2 ;P r =μC p / λ is the air Prandtl number (dimensionless), μ is the dynamic viscosity (Pa·s), C p is the specific heat capacity (J·kg -1 ·K -1 ), λ is the thermal conductivity (W·m -1 ·K -1 );

[0081] J0 and J2 are the first-kind Bessel functions of the zeroth and second orders, respectively;

[0082] sinh and cosh are the hyperbolic sine and cosine functions respectively;

[0083] w=2πf is the circular frequency. Those skilled in the art can understand that the method directly calculates and outputs the above formula through matlab programming, and the processed wind pressure time history.

[0084] Preferably, in step S5 of the above method, the distorted pressure measurement pipeline signal is corrected by the theoretical frequency response function to obtain the real signal time course C p0 (t), the conversion formula is:

[0085]

[0086] In the formula, real represents the real part of the complex number, FFT is the fast Fourier transform, and IFFT is the inverse fast Fourier transform. It can be understood by those skilled in the art that step S5 directly introduces the theoretical frequency response function through the above formula to correct the distorted pressure measurement pipeline signal and obtain the real signal time history C p0 (t).

[0087] Example

[0088] 1. The application project is located in Bijie City, Guizhou Province. It is a complex large-span spatial structure building. The building wind tunnel test model is as shown in the attached Figure 4As shown in the figure; according to the building shape, the smaller deformation is divided into Class I, and the larger deformation is divided into Class II. The division is shown in the attached Figure 5 , among which AA-2, 5, 7, 10, 11, 13, 14, 15, 18, 19, 22, 23, 25, 26, 27, 30, 31, 34, 35, 36, 39 are Class I; AA-1, 3, 4, 6, 8, 9, 12, 16, 17, 20, 21, 24, 28, 29, 32, 33, 35, 37, 38, 40 are Class II. The building surface measurement points are as follows Figure 6 shown.

[0089] 2. The water injection method is selected as the pressure measuring pipe diameter measurement method. The final internal radius is the average value of 5 test results, 0.5032mm, and the internal diameter is 1.0063mm. The measurement results are shown in the following table.

[0090]

[0091]

[0092] 3. Take one of the measuring points E5 as an example. After the wind tunnel test, the original wind pressure time history is as shown in the attached figure. Figure 2 As shown; Steps 4 and 5 are directly calculated and output by Matlab programming. The wind pressure time history after processing is shown in the attached Figure 1 As shown, take the 5th to 10th seconds of the total time course before and after correction and enlarge it as shown in the attached Figure 3 As shown, through the attached Figure 3 The comparison shows that the correction effect of this method is better.

[0093] The common values ​​are:

[0094] parameter Value parameter Value L Actual pressure tube length (m) T 298.15K R <![CDATA[5.032mm×10 -4 m]]> P 101000Pa γ 1.402 <![CDATA[ρ s ]]> <![CDATA[1.185kg / m 3 ]]> σ 0 μ <![CDATA[1.85×10 -5 Step]]> k 1.402 λ 0.0261W / (m·K) <![CDATA[C p ]]> 1007J / (kg·K)

Claims

1. A method for correcting signal distortion of pressure measuring pipelines on complex building surfaces in wind tunnel tests, characterized in that The steps include: S1. Make a building model, divide the area, and set measurement points; S2. Determine the diameter of the pressure measuring tube at the measuring point of the wind tunnel test; S3, conduct a wind tunnel test and process the results to obtain a wind pressure time history; S4, filtering the wind pressure time history; S5. Correct the distorted pressure measuring pipeline signal to obtain the real signal time history.

2. The method for correcting signal distortion of pressure measuring pipelines on complex building surfaces in wind tunnel tests according to claim 1 is characterized by: In step S1, the area of ​​a single area accounts for 1% to 5% of the total surface area of ​​the building, and the division principle can refer to the division principle of the building surface shape coefficient, where the area with larger deformation is divided into Class II, and the area with smaller deformation is divided into Class I.

3. The method for correcting signal distortion of pressure measuring pipeline on complex building surface in wind tunnel test according to claim 1, characterized in that: In step S2, the inner radius of the pressure measuring tube is measured by laser measurement.

4. The method for correcting signal distortion of pressure measuring pipelines on complex building surfaces in wind tunnel tests according to claim 1, characterized in that: In step S2, the inner radius of the pressure measuring tube is determined by the water injection method, and the water injection method includes the following steps: a. Select a pressure measuring tube with a length of L and put it into a dryer for drying, and use a test balance to measure its mass as m1; b. Then immerse the pressure measuring tube in water so that the tube is filled with water, then take out and wipe the water on the outer wall, and measure its weight again as m2; c. Calculate the inner radius of the pressure measuring tube as: Where ρ is the air density.

5. The method for correcting signal distortion of pressure measuring pipeline on complex building surface in wind tunnel test according to claim 3 or 4, characterized in that: At least five piezometers were randomly selected from the piezometer sample for aperture measurement, and the average of the five groups of aperture numbers was taken to obtain the inner radius of the experimental piezometer.

6. The method for correcting signal distortion of pressure measuring pipelines on complex building surfaces in wind tunnel tests according to claim 1, characterized in that: In step S3, a wind tunnel test is performed to obtain the test results, which are a bunch of electrical signal time histories, which need to be processed to obtain the wind pressure time histories. The formula used is: C pi (t) is the pressure coefficient at measuring point i at time t, P i (t) is the pressure acting on the measuring point i, P0 and P ∞ Respectively represent the total pressure and static pressure at the reference height.

7. The method for correcting signal distortion of pressure measuring pipelines on complex building surfaces in wind tunnel tests according to claim 1, characterized in that: In step S4, an integer n is selected as the size of the filtering segment. When the amount of wind pressure time history data is less than 15,000, n=4; When the amount of wind pressure time series data is greater than or equal to 15,000, n = 5; for each position t in the time series, the weighted values ​​of n consecutive data points from t-n+1 to t are calculated; the weighted values ​​are shown in the following table: When n=4, When n=5, And when t=1,2,3,4, C pi,move (t)=C pi (t)。 8. The method for correcting signal distortion of pressure measuring pipelines on complex building surfaces in wind tunnel tests according to claim 7, characterized in that: The obtained average value becomes the value of the new time series at position t. After the calculation is completed once, the filter segment is moved forward by one data point and the above calculation is repeated until the entire time series is covered.

9. The method for correcting signal distortion of pressure measuring pipelines on complex building surfaces in wind tunnel tests according to claim 7, characterized in that: In step S5, a theoretical frequency response function is introduced to correct the distorted pressure measurement pipeline signal. The solution formula of the theoretical frequency response function H(w) is: Category I: Category II: Where: V t =πR 2 L(m 3 ) is the internal volume of the pressure tube, L is the length of the pressure tube (m), R is the internal radius of the pressure tube (m); V is the internal cavity volume of the pressure sensor (m 3 ); σ is the dimensionless increment of the pressure sensor cavity deformation; k is the internal air variation factor associated with the pressure sensor cavity (dimensionless); γ is the specific heat ratio of air at the test temperature T0 (K) and pressure P0 (Pa); c=(γP0 / ρ s ) 1 / 2 is the speed of sound (m / s), ρ s is the air density under test conditions (kg / m 3 ); i=(-1) 1 / 2 ;P r =μC p / λ is the air Prandtl number (dimensionless), μ is the dynamic viscosity (Pa·s), C p is the specific heat capacity (J·kg -1 ·K -1 ), λ is the thermal conductivity (W·m -1 ·K -1 ); J0 and J2 are the first-kind Bessel functions of the zeroth and second orders, respectively; sinh and cosh are the hyperbolic sine and cosine functions respectively; w=2πf is the circular frequency.

10. The method for correcting signal distortion of pressure measuring pipelines on complex building surfaces in wind tunnel tests according to claim 9, characterized in that: In step S5, the distorted pressure measurement pipeline signal is corrected by the theoretical frequency response function to obtain the real signal time course C p0 (t), the conversion formula is: Where real represents the real part of the complex number, FFT is the fast Fourier transform, and IFFT is the inverse fast Fourier transform.

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