Method for correcting distortion of pressure tube signal of complex building surface in wind tunnel test

Abstract

The present application relates to a kind of wind tunnel test complex building surface pressure measuring pipe signal distortion correction method, it is related to wind tunnel test data processing field.This method includes the following steps: S1, building model is prepared, region is divided, and measurement point is set;S2, the pressure measuring tube diameter at measurement point of wind tunnel test is determined;S3, wind tunnel test is carried out, and the result is handled to obtain wind pressure time history;S4, wind pressure time history is filtered;S5, to the distorted pressure measuring pipe signal is corrected, and the real signal time history is obtained.This method can be more accurate by twice filtering, the pipe distortion problem that appears in pressure measurement time is corrected, it is suitable for the region of complex building deformation larger.And this method can effectively improve the accuracy of wind tunnel test measured data, better help production and scientific research work development.The existing method only considers the characteristics of pressure measuring tube, and the correction method is simple, and the problem of easy to produce error correction result is solved.

Description

Technical Field

[0001] This invention relates to a method for correcting signal distortion in pressure measuring pipelines on complex building surfaces during wind tunnel testing, and relates to the field of wind tunnel test data processing. Background Technology

[0002] Wind tunnel testing is one of the main methods for studying wind pressure on the surface of complex building structures, and pressure gauges are one of the main tools for measuring wind pressure. However, because the signal will be significantly distorted after passing through the pipeline system, the distortion of the pipeline signal will affect the average wind pressure, fluctuating wind pressure, energy spectrum, spatial correlation, and non-Gaussian properties of the building surface, making it impossible to accurately measure the wind pressure on the building surface.

[0003] Complex buildings, due to their varied shapes, require a greater number of pressure measurement holes than conventional buildings. Simultaneously, significant flow separation occurs at areas of substantial deformation in complex buildings. In these areas, pipe distortion amplifies or diminishes the wind pressure changes. The pipe distortion at large deformations differs from that at small deformations; therefore, it is necessary to employ special distortion correction methods at complex deformation sites.

[0004] The existing method corrects distortion using a fluid pipeline dissipation model. However, this approach only considers the characteristics of the pressure gauge itself, and the simple correction method is prone to producing erroneous results. Furthermore, using the same method for all measuring points increases the likelihood of incorrect corrections. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the existing methods only consider the characteristics of the pressure measuring tube itself, and the correction methods are simple and easy to produce erroneous correction results.

[0006] The technical solution adopted by this invention to solve its technical problem is: a method for correcting signal distortion in pressure measuring pipelines on complex building surfaces during wind tunnel testing, comprising the following steps:

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

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

[0009] S3. Conduct wind tunnel tests and process the results to obtain the wind pressure time history;

[0010] S4. Filter the wind pressure time history;

[0011] S5. Correct the distorted pressure measurement pipeline signal to obtain the true signal time history.

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

[0013] In step S2 of the above method, the internal radius of the pressure measuring tube is determined by laser measurement.

[0014] In the above method, step S2 uses a water injection method to determine the internal radius of the pressure measuring tube. The water injection method includes the following steps: a) selecting a pressure measuring tube of length L and drying it in a dryer, then measuring its mass as m1 using a test balance; b) immersing the pressure measuring tube in water until it is full, then removing it and wiping the water off the outer wall, and measuring its weight again as m2; c) calculating the internal radius of the pressure measuring tube as: Where ρ is the air density.

[0015] Furthermore, in the above method, at least 5 pressure measuring tubes are randomly selected from the pressure measuring tube sample for aperture measurement, and the average of the five aperture numbers is taken to obtain the internal radius of the experimental pressure measuring tube.

[0016] In step S3 of the above method, a wind tunnel test is conducted to obtain the test results, which are a series of electrical signal time histories. These need to be processed to obtain the wind pressure time histories. The formula used is as follows: C pi (t) is the pressure coefficient at time t at measuring point i, P i (t) represents the pressure acting at measuring point i, P0 and P ∞ These represent the total pressure and static pressure at the reference height, respectively.

[0017] In step S4 of the above method, 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 history data is greater than or equal to 15,000, n = 5. For each position t in the time series, the weighted value of n consecutive data points from t-n+1 to t is calculated. The weighted values ​​are shown in the table below:

[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).

[0024] 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.

[0025] Furthermore, in step S5 of the above method, a theoretical frequency response function is introduced to correct the distorted pressure measurement pipeline signal. The formula for solving the theoretical frequency response function H(w) is as follows:

[0026] Class I:

[0027]

[0028] Category II:

[0029]

[0030] In the formula: V t =πR 2 L(m 3 R is the internal volume of the pressure sensing tube, L is the length of the pressure sensing tube (m), R is the internal radius of the pressure sensing tube (m); V is the internal cavity volume of the pressure sensor (m³). 3 );

[0031] σ is the dimensionless increment of the deformation of the pressure sensor cavity;

[0032] k is a dimensionless internal air variation factor related to the pressure sensor cavity;

[0033] γ is the specific heat ratio of air at the test temperature T0 (K) and pressure P0 (Pa);

[0034] c=(γP0 / ρ s ) 1 / 2 For the speed of sound (m / s), ρ s The air density under the test conditions (kg / m³) 3 );

[0035] i = (-1) 1 / 2 ;P r =μC p / λ is the Prandtl number of air (dimensionless), μ is the dynamic viscosity (Pa·s), and C p Specific heat capacity (J·kg) -1 ·K -1 ), where λ is the thermal conductivity (W·m). -1 ·K -1 );

[0036] J0 and J2 are the zeroth and second order Bessel functions of the first kind, respectively;

[0037] sinh and cosh are hyperbolic sine and hyperbolic cosine functions, respectively;

[0038] w = 2πf is the angular frequency.

[0039] Furthermore, in step S5 of the above method, the distorted pressure measurement pipeline signal is corrected using a theoretical frequency response function to obtain the true signal time history C. p0 (t), the conversion formula is:

[0040]

[0041] In the formula, real represents taking the real part of the complex number, FFT is the Fast Fourier Transform, and IFFT is the Inverse Fast Fourier Transform.

[0042] The beneficial effects of this invention are: this method, through two filtering steps, can more accurately correct pipeline distortion problems that occur during pressure measurement, and also provides a suitable correction method for areas with large deformations in complex buildings. This method can effectively improve the accuracy of wind tunnel test data, and better support the development of production and scientific research. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the original wind pressure time history.

[0044] Figure 2 This is a schematic diagram of the wind pressure time history after the modification of this invention.

[0045] Figure 3 This is a schematic diagram comparing the time history of the present invention and the original wind pressure.

[0046] Figure 4 This is a schematic diagram of the architectural model structure of the present invention.

[0047] Figure 5 This is a schematic diagram of the zoning of the building model of the present invention.

[0048] Figure 6 This is a schematic diagram of the layout of measuring points on the building surface of the building model of the present invention. Detailed Implementation

[0049] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0050] like Figures 1 to 6 As shown, the method for correcting signal distortion in pressure measurement pipelines on complex building surfaces during wind tunnel testing according to the present invention includes the following steps:

[0051] S1. Create a building model, divide the area, and set measurement points;

[0052] S2. Determine the diameter of the pressure measuring tube at the measurement point in the wind tunnel test;

[0053] S3. Conduct wind tunnel tests and process the results to obtain the wind pressure time history;

[0054] S4. Filter the wind pressure time history;

[0055] S5. Correct the distorted pressure measurement pipeline signal to obtain the true signal time history. As those skilled in the art can understand, wind tunnel pressure measurement is a common method for studying the aerodynamic characteristics of a model. During the test, a pressure measurement pipe of a certain length is needed to connect the pressure measurement hole on the model surface to the pressure sensor. Therefore, the pressure signal obtained is not the true pressure on the model surface, but a distorted signal after interference from the pressure measurement pipe. The difference between the distorted signal and the true signal is mainly reflected in two aspects: (1) the signal energy (amplitude) is amplified or weakened; (2) the signal phase lags. Moreover, this difference will increase with the increase of the pressure measurement pipe length, and the pressure measurement pipe length in some large-scale pressure measurement tests has reached more than 2 meters, and the wind pressure signal will be severely distorted. For pressure measurement tests, the measured wind pressure signal is almost the basis for all subsequent data analysis, such as: obtaining the model's wind pressure coefficient, static three-component force coefficient, buffeting force spectrum, coherence function, etc. Therefore, before conducting a model wind tunnel pressure measurement test, it is necessary to first conduct a detailed study on the signal distortion problem of the pressure measurement pipeline and consider how to more accurately correct the distorted signal. Step S1 involves creating the required model and dividing the building surface into multiple regions. The number of regions can be several or dozens, depending on the actual complexity of the building. Since the diameter of pressure measuring tubes of the same specification may vary between different batches, the radius of each batch of pressure measuring tubes must be measured. Therefore, Step S2 involves on-site measurement to estimate the diameter of pressure measuring tubes within the same batch. Step S3 involves conducting wind tunnel tests to obtain the test results, which are a series of electrical signal time histories. These need to be processed to obtain the wind pressure time histories. Step S4 involves the first filtering of the wind pressure time histories. Step S5 introduces a theoretical frequency response function to correct the distorted pressure measuring tube signals and obtain the true signal time histories.

[0056] Preferably, in step S1 of the above method, the area of ​​a single region accounts for 1% to 5% of the total building surface area, and the division principle can refer to the division principle of the building surface shape coefficient, wherein areas with larger deformation are classified as Class II, and areas with smaller deformation are classified as Class I. Those skilled in the art will understand that, in practice, the present invention preferably uses an area of ​​5% to 1% of the total building surface area, that is, the number of divided regions is between 20 and 100, which can well balance calculation accuracy and efficiency. The division principle can refer to the division principle of the building surface shape coefficient, wherein areas with larger deformation are classified as Class II, and areas with smaller deformation are classified as Class I.

[0057] Preferably, in step S2 of the above method, the internal radius of the pressure measuring tube is determined using a laser measurement method. Those skilled in the art will understand that, to ensure data accuracy, this method uses a laser measurement method to determine the internal radius of the pressure measuring tube, and the laser measurement method is existing technology.

[0058] Preferably, in step S2 of the above method, the water injection method is used to determine the internal radius of the pressure measuring tube. The water injection method includes the following steps: a) Select a pressure measuring tube of length L and dry it in a dryer, then measure its mass as m1 using a test balance; b) Immerse the pressure measuring tube in water until it is full of water, then remove it and wipe the water off 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. Those skilled in the art will understand that, to ensure the accuracy of the internal radius data of the pressure measuring tube, this method employs a water injection method for determination. Specifically, this involves steps a) selecting a pressure measuring tube of length L and drying it in a dryer, then measuring its mass as m1 using a test balance; b) immersing the pressure measuring tube in water until it is completely filled, then removing it and wiping the water off the outer wall, and measuring its weight again as m2; c) calculating the internal radius of the pressure measuring tube as: Where ρ is the air density.

[0059] Preferably, in the above method, at least five pressure testing tubes are randomly selected from the pressure testing tube sample for orifice diameter measurement, and the average of the five orifice diameter values ​​is taken to obtain the internal radius of the experimental pressure testing tube. Those skilled in the art will understand that, to ensure the accuracy of the calculated data, considering that the tube diameters of pressure testing tubes of the same specification from different batches may vary, at least five pressure testing tubes are actually randomly selected from the pressure testing tube sample for orifice diameter measurement, and the average of the five orifice diameter values ​​is taken to obtain the internal radius of the experimental pressure testing tube.

[0060] Preferably, in step S3 of the above method, a wind tunnel test is conducted to obtain the test results, which are a set of electrical signal time histories. These need to be processed to obtain the wind pressure time histories, using the following formula: C pi (t) is the pressure coefficient at time t at measuring point i, P i (t) represents the pressure acting at measuring point i, P0 and P ∞ These represent the total pressure and static pressure at the reference height, respectively. Those skilled in the art will understand that, to obtain the wind pressure time history, this method uses the following formula: C pi (t) is the pressure coefficient at time t at measuring point i, P i (t) represents the pressure acting at measuring point i, P0 and P ∞ These represent the total pressure and static pressure at the reference height, respectively.

[0061] Preferably, in step S4 of the above method, 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 history data is greater than or equal to 15,000, n = 5. For each position t in the time series, the weighted value of n consecutive data points from t-n+1 to t is calculated; the weighted values ​​are shown in the table below:

[0062] When n=4

[0063]

[0064] When n=5

[0065]

[0066] And when t = 1, 2, 3, 4,

[0067] C pi,move (t)=C pi (t). As those skilled in the art will understand, step S4 performs a first filter on the wind pressure time history obtained in S3, specifically derived from the above formula.

[0068] Preferably, the average value obtained in the above method becomes the value of the new time series at position t. After one calculation, the filter segment is moved forward by one data point, and the above calculation is repeated until the entire time series is covered. Those skilled in the art will understand that, in order to ensure complete data coverage, the average value obtained in this method becomes the value of the new time series at position t. After one calculation, the filter segment is moved forward by one data point, and the above calculation is repeated until the entire time series is covered.

[0069] Preferably, in step S5 of the above method, a theoretical frequency response function is introduced to correct the distorted pressure measurement pipeline signal. The formula for solving the theoretical frequency response function H(w) is:

[0070] Class I:

[0071]

[0072] Category II:

[0073]

[0074] In the formula: V t =πR 2 L(m 3 R is the internal volume of the pressure sensing tube, L is the length of the pressure sensing tube (m), R is the internal radius of the pressure sensing tube (m); V is the internal cavity volume of the pressure sensor (m³). 3 );

[0075] σ is the dimensionless increment of the deformation of the pressure sensor cavity;

[0076] k is a dimensionless internal air variation factor related to the pressure sensor cavity;

[0077] γ is the specific heat ratio of air at the test temperature T0 (K) and pressure P0 (Pa);

[0078] c=(γP0 / ρ s ) 1 / 2 For the speed of sound (m / s), ρ s The air density under the test conditions (kg / m³) 3 );

[0079] i = (-1) 1 / 2 ;P r =μC p / λ is the Prandtl number of air (dimensionless), μ is the dynamic viscosity (Pa·s), and C p Specific heat capacity (J·kg) -1 ·K -1 ), where λ is the thermal conductivity (W·m). -1 ·K -1 );

[0080] J0 and J2 are the zeroth and second order Bessel functions of the first kind, respectively;

[0081] sinh and cosh are hyperbolic sine and hyperbolic cosine functions, respectively;

[0082] w = 2πf is the angular frequency. Those skilled in the art will understand that this method directly calculates and outputs the above formula using MATLAB programming, resulting in the processed wind pressure time history.

[0083] Preferably, in step S5 of the above method, the distorted pressure measurement pipeline signal is corrected using a theoretical frequency response function to obtain the true signal time history C. p0 (t), the conversion formula is:

[0084]

[0085] In the formula, real represents taking the real part of a complex number, FFT is Fast Fourier Transform, and IFFT is Inverse Fast Fourier Transform. Those skilled in the art will understand 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 true signal time history C. p0 (t).

[0086] Example

[0087] 1. The application project is located in Bijie City, Guizhou Province, and is a complex, large-span spatial structure building. The wind tunnel test model of the building is attached. Figure 4As shown in the attached diagram; based on the building's shape, areas with smaller deformations are classified as Category I, and areas with larger deformations are classified as Category II. The zoning details are as follows: Figure 5 Among them, AA-2, 5, 7, 10, 11, 13, 14, 15, 18, 19, 22, 23, 25, 26, 27, 30, 31, 34, 35, 36, and 39 are Class I; AA-1, 3, 4, 6, 8, 9, 12, 16, 17, 20, 21, 24, 28, 29, 32, 33, 35, 37, 38, and 40 are Class II. The measuring points on the building surface are attached. Figure 6 As shown.

[0088] 2. The water injection method was selected for the pressure testing pipe diameter measurement. The final internal radius was taken as the average of 5 test results, which was 0.5032 mm, and the internal diameter was taken as 1.0063 mm. The measurement results are shown in the table below.

[0089]

[0090]

[0091] 3. Taking measuring point E5 as an example, the original wind pressure time history obtained after wind tunnel testing is shown in the attached figure. Figure 2 As shown; the wind pressure time history is processed by directly calculating the output results through MATLAB programming in steps 4 and 5, as shown in the attached figure. Figure 1 As shown in the attached image, seconds 5-10 of the total time history before and after correction are magnified. Figure 3 As shown, through the attached Figure 3 The comparison shows that the correction effect of this method is better.

[0092] The general value is:

[0093] L Actual pressure measuring 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 0.0261 W / (m·K) <![CDATA[C p ]]> 1007 J / (kg·K)

Claims

1. A method for correcting signal distortion in pressure measuring pipelines on complex building surfaces during wind tunnel testing, characterized in that... Includes the following steps: S1. Create a building model, divide the area, and set measurement points; S2. Determine the diameter of the pressure measuring tube at the measurement point in the wind tunnel test; S3. Conduct wind tunnel tests and process the results to obtain the wind pressure time history; S4. Filter the wind pressure time history; S5. Correct the distorted pressure measurement pipeline signal to obtain the true signal time history; In step S1, the area of ​​a single region accounts for 1% to 5% of the total building surface area, and the division principle refers to the division principle of the building surface shape coefficient. Among them, the region with larger deformation is divided into Class II, and the region with smaller deformation is divided into Class I. In step S3, a wind tunnel test is conducted to obtain the test results, which are a series of electrical signal time histories. These need to be processed to obtain the wind pressure time histories. The formula used is: , For measuring points Place Pressure coefficient at any time To act on the measuring point Pressure at the location, and These represent the total pressure and static pressure at the reference height, respectively. In step S4, select an integer. As for the size of the filter segment, when the amount of wind pressure time history data is less than 15,000 records... =4; When the amount of wind pressure time history data is greater than or equal to 15,000 records. =5; for each position in the time series Calculate from - +1 to of The weighted values ​​of consecutive data points are shown in the table below. when When =4, ； when When =5, ； And when When =1, 2, 3, 4, ； Step S5 introduces a theoretical frequency response function to correct the distorted pressure measurement pipeline signal. The theoretical frequency response function... The solution formula is: Class I: ； Category II: ； ； ； ； In the formula: V t =πR 2 L(m 3 R is the internal volume of the pressure sensing tube, L is the length of the pressure sensing tube (m), R is the internal radius of the pressure sensing tube (m); V is the internal cavity volume of the pressure sensor (m³). 3 ); σ is the dimensionless increment of the deformation of the pressure sensor cavity; k is a dimensionless internal air change factor related to the cavity of the pressure sensor; γ is the specific heat ratio of air at the test temperature T0 (K) and pressure P0 (Pa); c=(γP0 / ρ s ) 1 / 2 For the speed of sound (m / s), ρ s The air density under the test conditions (kg / m³) 3 ); i=(-1) 1 / 2 ;P r =μC p / λ is the dimensionless Prandtl number of air, μ is the dynamic viscosity (Pa•s), and C p Specific heat capacity (J•kg) -1 •K -1 ), where λ is the thermal conductivity (W•m) -1 •K -1 ); J0 and J2 are the zeroth and second order Bessel functions of the first kind, respectively; sinh and cosh are hyperbolic sine and hyperbolic cosine functions, respectively; w=2πf is the angular frequency.

2. The method for correcting signal distortion in pressure measuring pipelines on complex building surfaces during wind tunnel testing according to claim 1, characterized in that: In step S2, the internal radius of the pressure measuring tube is determined using a laser measurement method.

3. The method for correcting signal distortion in pressure measuring pipelines on complex building surfaces during wind tunnel testing according to claim 1, characterized in that: In step S2, the internal radius of the pressure measuring tube is determined using the water injection method. The water injection method includes the following steps: a. Selecting a length of... The pressure measuring tube was placed in a dryer to dry, and its mass was measured using a test balance. b. Immerse the pressure measuring tube in water until it is full, then remove it and wipe the water off the outside. Measure its weight again. ; c. The internal radius of the pressure measuring tube is calculated as follows: ,in This refers to air density.

4. The method for correcting signal distortion in pressure measuring pipelines on complex building surfaces during wind tunnel testing according to claim 2 or 3, characterized in that: At least five pressure testing tubes were randomly selected from the pressure testing tube sample for orifice diameter measurement. The average of the five orifice diameters was taken to obtain the internal radius of the experimental pressure testing tube.

5. The method for correcting signal distortion in pressure measuring pipelines on complex building surfaces during wind tunnel testing according to claim 1, characterized in that: The resulting average value becomes the new time series at location. After calculating the value once, the filter segment is moved forward by one data point, and the above calculation is repeated until the entire time series is covered.

6. The method for correcting signal distortion in pressure measuring pipelines on complex building surfaces during wind tunnel testing according to claim 1, characterized in that: In step S5, the distorted pressure measurement pipeline signal is corrected using the theoretical frequency response function to obtain the true signal time history C. p0 (t), the conversion formula is: ； In the formula, real represents taking 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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