Wind tunnel three-dimensional flow field real-time monitoring system based on laser Doppler velocity measurement

Abstract

The invention discloses a wind tunnel three-dimensional flow field real-time monitoring system based on laser Doppler velocity measurement, and relates to the technical field of measurement. Preparing a monitoring module; the gradient forming module is used for forming a gradient distribution diagram of the preliminary monitoring points based on the monitoring values; the monitoring forming module divides the control area into a conventional control area and a specific control area; the model building module is used for forming a speed direction prediction model in the specific control region; and a monitoring real control module. By arranging a region classification module, a gradient formation module, a monitoring formation module, a model establishment module and a monitoring real control module, regulated and controlled target monitoring points can meet the monitoring precision requirement, meanwhile, results of the target monitoring points are different, data homogenization is small, the data processing amount can be reduced, and the monitoring precision is improved. And the direction of the speed is judged.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, in particular to a real-time monitoring system for three-dimensional flow fields in a wind tunnel based on laser Doppler velocity measurement. Background Art

[0002] A method for measuring airflow parameters and model aerodynamic characteristics in a wind tunnel. In order to obtain data on the aerodynamic characteristics of an aircraft through wind tunnel experiments, it is necessary to accurately measure both the aerodynamic characteristics of the model and the airflow parameters of the wind tunnel. The aerodynamic characteristics of the model that need to be measured generally include forces and moments, pressure distribution, and heat flow distribution. The airflow parameters that need to be measured generally include pressure, temperature, density, and velocity. Among these, the most important is the measurement of velocity, because changes in pressure, temperature, and density are proportional to velocity. Therefore, during measurement, except for the difference in the instruments, the settings of the monitoring points are similar.

[0003] When taking measurements, accuracy must be ensured. However, due to the different shapes of the objects being measured, the monitoring points for each measurement are different. Accuracy can be improved by increasing the number of monitoring points, but this will also generate too much homogeneous data during the wind tunnel experiment, which will slow down data processing. In addition, when measuring speed, not only its value but also its direction needs to be determined. Due to the different shapes of the objects being measured, it is difficult to determine the direction of the speed. Summary of the Invention

[0004] In order to solve the above technical problems, a real-time monitoring system for three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry is provided. This technical solution solves the problems raised in the above background technology.

[0005] In order to achieve the above objects, the technical solution adopted by the present invention is: The wind tunnel three-dimensional flow field real-time monitoring system based on laser Doppler velocimetry includes: an area classification module, wherein the area classification module obtains a three-dimensional model of the object under test in the wind tunnel, and obtains at least one regular area and at least one irregular area based on the three-dimensional model; A preliminary monitoring module, wherein the conditional preparation module obtains the maximum target wind speed of the measured object during speed measurement, forms at least one preliminary monitoring point in a regular area and an irregular area, and obtains a monitoring value of the preliminary monitoring point under the condition of the maximum target wind speed; A gradient forming module, wherein the gradient forming module forms a gradient distribution map of preliminary monitoring points based on the monitoring values; a monitoring formation module, the monitoring formation module obtaining an allowable monitoring error of the three-dimensional flow field of the wind tunnel, forming at least one control region based on the allowable monitoring error and a gradient distribution map, adjusting preliminary monitoring points in the control region, using the adjusted preliminary monitoring points as target monitoring points, and dividing the control region into a conventional control region and a specific control region; A model building module, wherein the model building module forms a velocity direction prediction model in a specific control area; The monitoring and actual control module sets a laser Doppler velocimeter at the target monitoring point, uses the laser Doppler velocimeter to measure the speed, and uses a speed direction prediction model to form a monitoring result of the target monitoring point.

[0006] Preferably, the step of analyzing and obtaining at least one regular region and at least one irregular region based on the three-dimensional model comprises the following steps: Obtaining a wind speed movement direction during a wind tunnel test, and using at least one equally spaced vertical plane along the wind speed movement direction to intersect with the surface of the three-dimensional model to obtain at least one closed contour line; Get the tangent of the points on the closed contour line, take the points on the closed contour line with the vertical direction as feature points, and use the feature points to split the closed contour line into sampling contour lines; Use at least one equally spaced characteristic surface perpendicular to the wind speed movement direction to intersect the sampling contour line to obtain at least one sampling point, number the sampling points on the sampling contour line from small to large according to the wind speed movement direction, obtain the tangent plane of the three-dimensional model at the sampling point, and obtain the normal vector of the tangent plane at the corresponding sampling point; When two adjacent sampling points are located on the same sampling contour line and have the same normal vector direction, the two adjacent sampling points are of the same type; When two adjacent sampling points are located on the same feature surface and have the same normal vector direction, the two adjacent sampling points are of the same type; Aggregate adjacent sampling points with similar relationships to obtain a sampling point set; The surface area of ​​the three-dimensional model covered by the sampling points in the sampling point set is regarded as a regular area; At least one connected portion of the three-dimensional model surface other than the regular area is regarded as an irregular area.

[0007] Preferably, forming at least one preliminary monitoring point in the regular area and the irregular area comprises the following steps: The sampling points with the largest and smallest numbers on the same sampling contour line contained in the regular area are used as preliminary monitoring points; The sampling points whose tangent planes contained in the irregular area are parallel to the wind speed movement direction are taken as the preliminary monitoring points.

[0008] Preferably, forming a gradient distribution map of preliminary monitoring points based on the monitoring values ​​comprises the following steps: Connect adjacent preliminary monitoring points on the same sampling contour line in sequence to form at least one gradient longitudinal line; Connect adjacent preliminary monitoring points on the same feature surface in sequence to form at least one gradient horizontal line; The monitoring values ​​of the preliminary monitoring points at the end points of the gradient vertical line are subtracted to form a measurement gradient, and the monitoring values ​​of the preliminary monitoring points at the end points of the gradient horizontal line are subtracted to form a measurement gradient. The measurement gradient is assigned to the corresponding gradient vertical line or gradient horizontal line to form a gradient distribution map.

[0009] Preferably, forming at least one control area based on the allowable monitoring error and the gradient distribution map comprises the following steps: In regular or irregular areas, the gradient vertical lines located on the same sampling contour line are merged into the gradient integrated vertical line; The maximum absolute value of the measured gradient of the gradient horizontal lines connected between adjacent gradient integrated vertical lines is used as the identification value; In the regular region or the irregular region, all possible combinations of gradient integrated vertical lines are obtained, and the regular region or the irregular region is divided into at least one preliminary region using the gradient integrated vertical lines in the possible combinations; Accumulating the identification values ​​of adjacent gradient integrated vertical lines in the preparation area to obtain a screening value of the preparation area; The error coefficient of the possible combination of situations is obtained by subtracting the screening value of the preparation area corresponding to the possible combination of situations from the allowable monitoring error and taking the average value; The preparation area corresponding to the possible combination with the smallest error coefficient is used as the control area.

[0010] Preferably, the adjusting of the preliminary monitoring points in the control area comprises the following steps: Delete the horizontal gradient line and the preliminary monitoring points of its endpoints that do not touch the edge of the control area. When the preliminary monitoring points at both ends of the vertical gradient line are deleted, delete the vertical gradient line. When the absolute value of the measured gradient of the gradient vertical line in the control area is greater than the allowable monitoring error, the absolute value of the measured gradient and the allowable monitoring error are rounded to obtain the target value; At least one identification point is evenly selected on the gradient vertical line where the measured gradient exceeds the allowable monitoring error. The number of identification points is equal to the target value, and the identification points are used as additional locations for preliminary monitoring points. When the absolute value of the measured gradient of the gradient longitudinal line in the control area does not exceed the allowable monitoring error, only one of the preliminary monitoring points at both ends of the gradient longitudinal line is retained.

[0011] Preferably, dividing the control region into a conventional control region and a specific control region comprises the following steps: The control area generated by the irregular area and facing the direction of wind speed movement is regarded as the specific control area; The control area where the irregular area is generated and faces the opposite direction of the wind speed movement is regarded as the regular control area; The control area generated by the rule area is used as the regular control area.

[0012] Preferably, forming a velocity direction prediction model in the specific control area includes the following steps: Taking at least one sample point in the specific control area, obtaining a tangent plane of the three-dimensional model at the sample point as a sample plane; Obtain the angle between the sample plane and the wind speed direction as the characteristic angle, and take the average of the characteristic angles corresponding to the sample points in the specific control area to obtain the sample angle; The twice of the sample angle is used as the direction prediction angle.

[0013] Preferably, the speed measurement using a laser Doppler velocimeter comprises the following steps: During wind speed testing, scattering particles are added to the air fluid and the concentration of the scattering particles is regulated to ensure that when the wind speed remains unchanged, the change in the measurement value of the laser Doppler velocimeter is less than the allowable monitoring error.

[0014] Preferably, the use of the speed direction prediction model to form the monitoring result of the target monitoring point includes the following steps: Obtain the actual speed value of the target monitoring point in the specific control area during actual measurement. When the target monitoring point is in the conventional control area, the direction of the measured speed value is along the direction of wind speed movement; When the target monitoring point is in the specific control area, the angle between the direction of the measured speed value and the direction of wind speed movement is the direction prediction angle.

[0015] Compared with the prior art, the present invention has the following beneficial effects: By setting up the regional classification module, gradient formation module, monitoring formation module, model building module and monitoring control module, different monitoring points can be set according to the three-dimensional model of the object to be measured, more monitoring points can be set in areas with large speed changes, and fewer monitoring points can be set in areas with small speed changes. Through the analysis of the results of the preliminary monitoring, the preliminary monitoring points are adjusted so that the target monitoring points after adjustment can meet the monitoring accuracy requirements. At the same time, there are differences in the results between the target monitoring points, and the data homogeneity is small, so the data quality is high, which can reduce the amount of data processing. At the same time, the direction of the speed is judged based on physical knowledge and the differences in the monitoring area, thereby improving the completeness of the monitoring data. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the process of the real-time monitoring system of three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry of the present invention; Figure 2 A schematic diagram of a process of analyzing and obtaining at least one regular area and at least one irregular area based on a three-dimensional model according to the present invention; Figure 3 A schematic diagram of a process for forming at least one preliminary monitoring point in a regular area and an irregular area according to the present invention; Figure 4 It is a schematic diagram of the process of forming a gradient distribution map of preliminary monitoring points based on monitoring values ​​according to the present invention; Figure 5 A schematic diagram of a process for forming at least one control area based on an allowable monitoring error and a gradient distribution diagram of the present invention; Figure 6 A schematic diagram of a process for adjusting preliminary monitoring points in a control area according to the present invention; Figure 7 This is a flow chart of dividing the control area into a conventional control area and a specific control area according to the present invention; Figure 8 Schematic diagram of the process of forming a velocity direction prediction model in a specific control area of ​​the present invention; Figure 9 This is a flow chart of using the speed direction prediction model of the present invention to generate monitoring results of a target monitoring point. DETAILED DESCRIPTION

[0017] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.

[0018] Reference Figure 1 As shown in FIG, a real-time monitoring system for three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry includes: an area classification module, wherein the area classification module obtains a three-dimensional model of the object under test in the wind tunnel, and obtains at least one regular area and at least one irregular area based on the three-dimensional model; A preliminary monitoring module, wherein the conditional preparation module obtains the maximum target wind speed of the measured object during speed measurement, forms at least one preliminary monitoring point in a regular area and an irregular area, and obtains a monitoring value of the preliminary monitoring point under the condition of the maximum target wind speed; A gradient forming module, wherein the gradient forming module forms a gradient distribution map of preliminary monitoring points based on the monitoring values; a monitoring formation module, the monitoring formation module obtaining an allowable monitoring error of the three-dimensional flow field of the wind tunnel, forming at least one control region based on the allowable monitoring error and a gradient distribution map, adjusting preliminary monitoring points in the control region, using the adjusted preliminary monitoring points as target monitoring points, and dividing the control region into a conventional control region and a specific control region; A model building module, wherein the model building module forms a velocity direction prediction model in a specific control area; The monitoring and actual control module sets a laser Doppler velocimeter at the target monitoring point, uses the laser Doppler velocimeter to measure the speed, and uses a speed direction prediction model to form a monitoring result of the target monitoring point.

[0019] When the objects to be measured are different, their structures are different. Usually, some parts are flat and some parts are irregular. In the flat part, the wind speed changes little, so fewer monitoring points are set, otherwise it will lead to serious data homogeneity. The specific number needs to be determined based on the measurement results. For the irregular part, due to the large speed variation, more monitoring points need to be set. In this solution, corresponding steps are set to set points for different objects to be measured in an orderly manner to ensure that the number of points is small enough. At the same time, the measurement accuracy meets the requirements. A small number of monitoring points will have a great impact on the wind tunnel experiment, because during the wind tunnel experiment, measurements will be performed under different wind speed conditions, and many groups of data will be generated. When each group of data contains a large amount of homogeneous data, the amount to be processed will be significantly increased.

[0020] Reference Figure 2 As shown, based on the three-dimensional model, analyzing and obtaining at least one regular area and at least one irregular area includes the following steps: Obtaining a wind speed movement direction during a wind tunnel test, and using at least one equally spaced vertical plane along the wind speed movement direction to intersect with the surface of the three-dimensional model to obtain at least one closed contour line; Get the tangent of the points on the closed contour line, take the points on the closed contour line with the vertical direction as feature points, and use the feature points to split the closed contour line into sampling contour lines; Use at least one equally spaced characteristic surface perpendicular to the wind speed movement direction to intersect the sampling contour line to obtain at least one sampling point, number the sampling points on the sampling contour line from small to large according to the wind speed movement direction, obtain the tangent plane of the three-dimensional model at the sampling point, and obtain the normal vector of the tangent plane at the corresponding sampling point; When two adjacent sampling points are located on the same sampling contour line and have the same normal vector direction, the two adjacent sampling points are of the same type; When two adjacent sampling points are located on the same feature surface and have the same normal vector direction, the two adjacent sampling points are of the same type; Aggregate adjacent sampling points with similar relationships to obtain a sampling point set; The surface area of ​​the three-dimensional model covered by the sampling points in the sampling point set is regarded as a regular area; At least one connected portion of the three-dimensional model surface other than the regular area is regarded as an irregular area.

[0021] The distinction between regular areas and irregular areas is mainly based on the direction of their normal vectors. In order to understand the above method, consider two cases as examples. The first is a horizontal cylinder whose side is parallel to the wind speed direction. Using the above method, the sampling points on the side of the cylinder are all of the same type, so it is determined as a regular area and fewer preliminary monitoring points can be set. The second is a sphere, on which the sampling points are not of the same type, so it is determined as an irregular area.

[0022] Reference Figure 3 As shown, forming at least one preliminary monitoring point in a regular area and an irregular area includes the following steps: The sampling points with the largest and smallest numbers on the same sampling contour line contained in the regular area are used as preliminary monitoring points; The sampling points whose tangent planes contained in the irregular area are parallel to the wind speed movement direction are taken as the preliminary monitoring points.

[0023] In the regular area, its change is regular. Therefore, the sampling points with the largest and smallest numbers on the same sampling contour line in the regular area are used as preliminary monitoring points. Here, two edge points along the wind speed movement direction in the regular area are selected. The reason is that the data of the preliminary monitoring points on the same sampling contour line here change linearly. According to the monitoring values ​​of the preliminary monitoring points under the condition of the maximum target wind speed, the preliminary monitoring points can be added through the linear relationship. The changes in irregular areas are irregular. The sampling points in the irregular areas where the tangent plane is parallel to the wind speed movement direction are used as preliminary monitoring points. The reason is that due to the setting method of the preliminary monitoring points, the part of the irregular area between two adjacent preliminary monitoring points must be facing the wind speed direction or back to the wind speed direction, and the two situations will not appear in parallel. Because when an area contains surfaces facing the wind speed direction or back to the wind speed direction at the same time, then in the process of change, there will inevitably be points where the tangent plane is parallel to the wind speed movement direction. Then the situation between adjacent preliminary monitoring points can also be regarded as approximately linear, and preliminary monitoring points can be added later through linear relationships.

[0024] Reference Figure 4 As shown, forming a preliminary gradient distribution map of monitoring points based on the monitoring values ​​includes the following steps: Connect adjacent preliminary monitoring points on the same sampling contour line in sequence to form at least one gradient longitudinal line; Connect adjacent preliminary monitoring points on the same feature surface in sequence to form at least one gradient horizontal line; The monitoring values ​​of the preliminary monitoring points at the end points of the gradient vertical line are subtracted to form a measurement gradient, and the monitoring values ​​of the preliminary monitoring points at the end points of the gradient horizontal line are subtracted to form a measurement gradient. The measurement gradient is assigned to the corresponding gradient vertical line or gradient horizontal line to form a gradient distribution map.

[0025] The measurement gradient is the difference between the monitoring of two adjacent preliminary monitoring points, which can be used to determine the difference between the monitoring of two preliminary monitoring points. When the difference is very small, one of the points can be deleted.

[0026] Reference Figure 5 As shown, forming at least one control area based on the allowable monitoring error and the gradient distribution map includes the following steps: In regular or irregular areas, the gradient vertical lines located on the same sampling contour line are merged into the gradient integrated vertical line; The maximum absolute value of the measured gradient of the gradient horizontal lines connected between adjacent gradient integrated vertical lines is used as the identification value; In the regular region or the irregular region, all possible combinations of gradient integrated vertical lines are obtained, and the regular region or the irregular region is divided into at least one preliminary region using the gradient integrated vertical lines in the possible combinations; Accumulating the identification values ​​of adjacent gradient integrated vertical lines in the preparation area to obtain a screening value of the preparation area; The error coefficient of the possible combination of situations is obtained by subtracting the screening value of the preparation area corresponding to the possible combination of situations from the allowable monitoring error and taking the average value; The preparation area corresponding to the possible combination with the smallest error coefficient is used as the control area.

[0027] The sampling contours and sampling points are set relatively densely. This is because, in order to obtain the required monitoring points, it is necessary to set an excessive number of sampling points at the beginning and form preliminary monitoring points. Under the condition of the maximum target wind speed, the monitoring value of the preliminary monitoring point only appears once. Therefore, even if too many monitoring points are set, it will not have a big impact. However, the target monitoring point obtained according to the analysis of this condition can meet all the measurement conditions. Because the remaining wind speeds are smaller, the error of the target monitoring point is smaller. The sampling contour lines are set relatively densely, and the preliminary monitoring points connected by the gradient horizontal lines in adjacent sampling contour lines can be merged. Therefore, the control area is divided as above.

[0028] Reference Figure 6As shown, adjusting the initial monitoring points in the control area includes the following steps: Delete the horizontal gradient line and the preliminary monitoring points of its endpoints that do not touch the edge of the control area. When the preliminary monitoring points at both ends of the vertical gradient line are deleted, delete the vertical gradient line. When the absolute value of the measured gradient of the gradient vertical line in the control area is greater than the allowable monitoring error, the absolute value of the measured gradient and the allowable monitoring error are rounded to obtain the target value; At least one identification point is evenly selected on the gradient vertical line where the measured gradient exceeds the allowable monitoring error. The number of identification points is equal to the target value, and the identification points are used as additional locations for preliminary monitoring points. When the absolute value of the measured gradient of the gradient longitudinal line in the control area does not exceed the allowable monitoring error, only one of the preliminary monitoring points at both ends of the gradient longitudinal line is retained.

[0029] The distance between the preliminary monitoring points set in the direction of wind speed movement may be large, so the gap may be large. Therefore, it is necessary to analyze the monitoring results obtained to determine whether additional monitoring points need to be set. When additional monitoring points are set, they should be set according to their linear relationship. In this way, the gap between the monitoring results of adjacent preliminary monitoring points in the direction of wind speed movement after the additional monitoring points is ensured to be small. Therefore, the monitoring results of all preliminary monitoring points can be used to characterize the overall situation of the area where they are located, and the error is very small.

[0030] Reference Figure 7 As shown, dividing the control area into a conventional control area and a specific control area includes the following steps: The control area generated by the irregular area and facing the direction of wind speed movement is regarded as the specific control area; The control area where the irregular area is generated and faces the opposite direction of the wind speed movement is regarded as the regular control area; The control area generated by the rule area is used as the regular control area.

[0031] The special control area faces the direction of wind speed movement, and the direction of wind speed will change due to collision. Therefore, for the special control area, it is necessary to additionally determine the direction of wind speed. The rest of the areas maintain the direction of wind speed movement because there is no collision.

[0032] Reference Figure 8 As shown, in the specific control area, forming a velocity direction prediction model includes the following steps: Taking at least one sample point in the specific control area, obtaining a tangent plane of the three-dimensional model at the sample point as a sample plane; Obtain the angle between the sample plane and the wind speed direction as the characteristic angle, and take the average of the characteristic angles corresponding to the sample points in the specific control area to obtain the sample angle; The twice of the sample angle is used as the direction prediction angle.

[0033] According to the relationship between the incident angle of impact and the reflection angle of impact, it is easy to know through geometric drawing that the direction prediction angle is the angle between the speed after impact and the direction of wind speed movement.

[0034] Velocimetry using a laser Doppler velocimeter involves the following steps: During wind speed testing, scattering particles are added to the air fluid and the concentration of the scattering particles is regulated to ensure that when the wind speed remains unchanged, the change in the measurement value of the laser Doppler velocimeter is less than the allowable monitoring error.

[0035] Laser Doppler velocimeters cannot directly identify airflow; they need to mix scattered particles into the air of the wind tunnel experiment. By identifying the speed of the scattered particles, they can then identify the speed at various locations on the object being measured.

[0036] Reference Figure 9 As shown, using the speed direction prediction model to form the monitoring results of the target monitoring point includes the following steps: Obtain the actual speed value of the target monitoring point in the specific control area during actual measurement. When the target monitoring point is in the conventional control area, the direction of the measured speed value is along the direction of wind speed movement; When the target monitoring point is in the specific control area, the angle between the direction of the measured speed value and the direction of wind speed movement is the direction prediction angle.

[0037] Furthermore, the present solution also proposes a storage medium on which a computer-readable program is stored. When the computer-readable program is called, it executes the above-mentioned real-time monitoring system for three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry.

[0038] It is understandable that the storage medium may be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; an optical medium, such as a DVD; or a semiconductor medium, such as a solid state disk (SSD).

[0039] In summary, the advantages of the present invention are: by setting a regional classification module, a gradient formation module, a monitoring formation module, a model building module and a monitoring control module, different monitoring points can be set according to the three-dimensional model of the object to be measured, more monitoring points can be set in areas with large speed changes, and fewer monitoring points can be set in areas with small speed changes. Through the analysis of the results of the preliminary monitoring, the preliminary monitoring points are regulated so that the target monitoring points after regulation can meet the monitoring accuracy requirements. At the same time, there are differences in the results between the target monitoring points, and the data homogeneity is small, so the data quality is high, thereby reducing the amount of data processing. At the same time, the direction of the speed is judged according to physical knowledge and the difference in the monitoring area, thereby improving the completeness of the monitoring data.

[0040] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A real-time monitoring system for three-dimensional flow fields in a wind tunnel based on laser Doppler velocimetry, characterized by: include: an area classification module, wherein the area classification module obtains a three-dimensional model of the object under test in the wind tunnel, and obtains at least one regular area and at least one irregular area based on the three-dimensional model; A preliminary monitoring module, wherein the conditional preparation module obtains the maximum target wind speed of the measured object during speed measurement, forms at least one preliminary monitoring point in a regular area and an irregular area, and obtains a monitoring value of the preliminary monitoring point under the condition of the maximum target wind speed; A gradient forming module, wherein the gradient forming module forms a gradient distribution map of preliminary monitoring points based on the monitoring values; a monitoring formation module, the monitoring formation module obtaining an allowable monitoring error of the three-dimensional flow field of the wind tunnel, forming at least one control region based on the allowable monitoring error and a gradient distribution map, adjusting preliminary monitoring points in the control region, using the adjusted preliminary monitoring points as target monitoring points, and dividing the control region into a conventional control region and a specific control region; A model building module, wherein the model building module forms a velocity direction prediction model in a specific control area; The monitoring and actual control module sets a laser Doppler velocimeter at the target monitoring point, uses the laser Doppler velocimeter to measure the speed, and uses a speed direction prediction model to form a monitoring result of the target monitoring point.

2. The real-time monitoring system for three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry according to claim 1 is characterized in that: The step of analyzing and obtaining at least one regular region and at least one irregular region based on the three-dimensional model comprises the following steps: Obtaining a wind speed movement direction during a wind tunnel test, and using at least one equally spaced vertical plane along the wind speed movement direction to intersect with the surface of the three-dimensional model to obtain at least one closed contour line; Get the tangent of the points on the closed contour line, take the points on the closed contour line with the vertical direction as feature points, and use the feature points to split the closed contour line into sampling contour lines; Use at least one equally spaced characteristic surface perpendicular to the wind speed movement direction to intersect the sampling contour line to obtain at least one sampling point, number the sampling points on the sampling contour line from small to large according to the wind speed movement direction, obtain the tangent plane of the three-dimensional model at the sampling point, and obtain the normal vector of the tangent plane at the corresponding sampling point; When two adjacent sampling points are located on the same sampling contour line and have the same normal vector direction, the two adjacent sampling points are of the same type; When two adjacent sampling points are located on the same feature surface and have the same normal vector direction, the two adjacent sampling points are of the same type; Aggregate adjacent sampling points with similar relationships to obtain a sampling point set; The surface area of ​​the three-dimensional model covered by the sampling points in the sampling point set is regarded as a regular area; At least one connected portion of the three-dimensional model surface other than the regular area is regarded as an irregular area.

3. The real-time monitoring system for three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry according to claim 2 is characterized in that: The forming of at least one preliminary monitoring point in the regular area and the irregular area comprises the following steps: The sampling points with the largest and smallest numbers on the same sampling contour line contained in the regular area are used as preliminary monitoring points; The sampling points whose tangent planes contained in the irregular area are parallel to the wind speed movement direction are taken as the preliminary monitoring points.

4. The real-time monitoring system for three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry according to claim 3 is characterized in that: The forming of the gradient distribution map of the preliminary monitoring points based on the monitoring values ​​comprises the following steps: Connect adjacent preliminary monitoring points on the same sampling contour line in sequence to form at least one gradient longitudinal line; Connect adjacent preliminary monitoring points on the same feature surface in sequence to form at least one gradient horizontal line; The monitoring values ​​of the preliminary monitoring points at the end points of the gradient vertical line are subtracted to form a measurement gradient, and the monitoring values ​​of the preliminary monitoring points at the end points of the gradient horizontal line are subtracted to form a measurement gradient. The measurement gradient is assigned to the corresponding gradient vertical line or gradient horizontal line to form a gradient distribution map.

5. The real-time monitoring system for three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry according to claim 4 is characterized in that: The forming of at least one control region based on the allowable monitoring error and the gradient distribution map comprises the following steps: In regular or irregular areas, the gradient vertical lines located on the same sampling contour line are merged into the gradient integrated vertical line; The maximum absolute value of the measured gradient of the gradient horizontal lines connected between adjacent gradient integrated vertical lines is used as the identification value; In the regular region or the irregular region, all possible combinations of gradient integrated vertical lines are obtained, and the regular region or the irregular region is divided into at least one preliminary region using the gradient integrated vertical lines in the possible combinations; Accumulating the identification values ​​of adjacent gradient integrated vertical lines in the preparation area to obtain a screening value of the preparation area; The error coefficient of the possible combination of situations is obtained by subtracting the screening value of the preparation area corresponding to the possible combination of situations from the allowable monitoring error and taking the average value; The preparation area corresponding to the possible combination with the smallest error coefficient is used as the control area.

6. The real-time monitoring system for three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry according to claim 5 is characterized in that: The adjustment of the preliminary monitoring points in the control area comprises the following steps: Delete the horizontal gradient line and the preliminary monitoring points of its endpoints that do not touch the edge of the control area. When the preliminary monitoring points at both ends of the vertical gradient line are deleted, delete the vertical gradient line. When the absolute value of the measured gradient of the gradient vertical line in the control area is greater than the allowable monitoring error, the absolute value of the measured gradient and the allowable monitoring error are rounded to obtain the target value; At least one identification point is evenly selected on the gradient vertical line where the measured gradient exceeds the allowable monitoring error. The number of identification points is equal to the target value, and the identification points are used as additional locations for preliminary monitoring points. When the absolute value of the measured gradient of the gradient longitudinal line in the control area does not exceed the allowable monitoring error, only one of the preliminary monitoring points at both ends of the gradient longitudinal line is retained.

7. The real-time monitoring system for three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry according to claim 6, characterized in that: The method of dividing the control area into a conventional control area and a specific control area comprises the following steps: The control area generated by the irregular area and facing the direction of wind speed movement is regarded as the specific control area; The control area where the irregular area is generated and faces the opposite direction of the wind speed movement is regarded as the regular control area; The control area generated by the rule area is used as the regular control area.

8. The real-time monitoring system for three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry according to claim 7, characterized in that: The forming of the velocity direction prediction model in the specific control region includes the following steps: Taking at least one sample point in the specific control area, obtaining a tangent plane of the three-dimensional model at the sample point as a sample plane; Obtain the angle between the sample plane and the wind speed direction as the characteristic angle, and take the average of the characteristic angles corresponding to the sample points in the specific control area to obtain the sample angle; The twice of the sample angle is used as the direction prediction angle.

9. The real-time monitoring system for three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry according to claim 8, characterized in that: The laser Doppler velocimeter is used to measure the velocity, which comprises the following steps: During wind speed testing, scattering particles are added to the air fluid and the concentration of the scattering particles is regulated to ensure that when the wind speed remains unchanged, the change in the measurement value of the laser Doppler velocimeter is less than the allowable monitoring error.

10. The real-time monitoring system for three-dimensional flow field in a wind tunnel based on laser Doppler velocimetry according to claim 9, characterized in that: The method of using the speed direction prediction model to form the monitoring result of the target monitoring point includes the following steps: Obtain the actual speed value of the target monitoring point in the specific control area during actual measurement. When the target monitoring point is in the conventional control area, the direction of the measured speed value is along the direction of wind speed movement; When the target monitoring point is in the specific control area, the angle between the direction of the measured speed value and the direction of wind speed movement is the direction prediction angle.

Images