A method of power turbulent flow measurement

Abstract

The application discloses a power turbulent flow measuring method, which adopts a hot-wire anemometer with two hot-wire probes to measure wind speeds of two points in space; then sets a sampling frequency fc, a statistical average time ts and a space length r of the hot-wire anemometer; obtains voltage data output by the hot-wire anemometer and discriminates whether the voltage data is normal or not, and eliminates abnormal data; obtains corrected voltage data; calculates a wind speed u according to the corrected voltage data; determines a time interval td according to the pre-set sampling frequency fc, and calculates a second-order and third-order turbulent flow dissipation rate by combining the wind speed measured by the two hot-wire probes; and sequentially calculates a kinematic viscosity coefficient v2 of an in-situ measurement position, an internal scale l0 of atmospheric turbulent flow and a turbulent degree I. The power turbulent flow measuring method overcomes the shortcomings that a temperature fluctuation instrument cannot measure power turbulent flow and an ultrasonic wind speed meter platform has poor applicability, and has the advantages of simple operation, applicability to severe environments, and high-altitude turbulent flow measurement by being carried on a sounding balloon.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of atmospheric optical measurement technology, especially a kind of dynamic turbulence measurement method. BACKGROUND

[0002] Atmospheric turbulence is an important movement form in atmosphere, its existence makes the vertical and horizontal exchange of momentum, heat, water vapor and pollutants in atmosphere significantly enhanced, far greater than the exchange intensity of molecular movement.Atmospheric turbulence is mainly caused by solar radiation and various meteorological factors, the fluctuation of atmospheric wind field caused by random movement of atmosphere has important influence on atmospheric boundary layer process, pollutant transport and diffusion and atmospheric propagation of light wave.At the same time, the turbulence caused by horizontal wind shear in high altitude is an important factor causing high altitude flight jolt, the vertical shear of near-surface wind has important role in inducing low altitude flight jolt when airplane takes off and lands.The existence of atmospheric turbulence also has certain interference effect on the propagation of light wave, sound wave and electromagnetic wave in atmosphere.Due to limited observation means, the research and cognition of atmospheric wind field fluctuation characteristics, especially high altitude atmospheric wind field fluctuation characteristics are relatively lack, direct measurement of dynamic turbulence has important significance for studying atmospheric turbulence.

[0003] Atmospheric turbulence is generally divided into two categories: dynamic turbulence and thermal turbulence.The intensity of atmospheric thermal turbulence is usually measured by temperature fluctuation instrument, the turbulence measured by the temperature fluctuation instrument is caused by thermal convection, and the dynamic turbulence caused by wind field change cannot be measured.Dynamic turbulence is usually measured by ultrasonic anemometer.Ultrasonic anemometer is to measure the transmission time of ultrasonic wave pulse at a certain distance on three non-orthogonal axes, through coordinate transformation, to obtain three components of wind speed and ultrasonic virtual temperature, by using the function relationship that sound speed is temperature and humidity.However, there are two problems in measuring dynamic turbulence by ultrasonic anemometer: (1) ultrasonic anemometer measures spatial single-point acoustic wind speed time series data, and Taylor assumption is needed to solve the spatial dynamic turbulence parameters; (2) due to the limitation of weight and power consumption, ultrasonic anemometer is usually suitable for ground measurement, and it is difficult to be carried on unmanned aerial vehicle, sounding and other platforms for high altitude turbulence measurement.

[0004] Hot-wire anemometers are commonly used for fluid velocity measurement. Due to their advantages such as high dynamic response, high accuracy, minimal interference with the flow field, and portability, hot-wire anemometers play an indispensable role in turbulence pulsation measurement. A hot-wire anemometer works by keeping the temperature of a hot-wire resistor constant in the flow field. When the wind speed changes, the current flowing through the hot-wire resistor changes, causing a change in the voltage across its terminals. The wind speed data of the current flow field is obtained by analyzing the relationship between the voltage signal and the wind speed. In existing technologies, conventional hot-wire anemometers measure time-series data of acoustic wind speed at a single point in space. Calculations of dynamic turbulence parameters in space require the use of Taylor assumptions. Furthermore, conventional hot-wire anemometers are mostly used for measurements on fixed platforms in turbulence measurements. On moving platforms, interference from platform vibration and rotation introduces measurement errors into the turbulence measurement. Conventional hot-wire anemometers are typically tested and calibrated in flow fields at room temperature, but larger errors occur under non-calibration conditions such as high temperature and high pressure. Summary of the Invention

[0005] To overcome the shortcomings of the existing technologies, this invention provides a dynamic turbulence measurement method and computer program product, which solves the problems that existing temperature pulsation meters cannot measure dynamic turbulence, that wind speed data measured by ultrasonic anemometers and conventional hot-wire anemometers cannot directly yield dynamic turbulence-related turbulence parameters, and that ultrasonic anemometers and conventional hot-wire anemometers have poor platform applicability.

[0006] The present invention adopts the following technical solution to solve the technical problem.

[0007] The present invention provides a method for measuring dynamic turbulence, which mainly includes the following steps:

[0008] Step 1: Use a hot-wire anemometer with two hot-wire probes to measure the wind speed at two points in space;

[0009] Step 2: After setting up the hot-wire anemometer, set the sampling frequency fc, statistical averaging time ts, and spatial length r of the hot-wire anemometer;

[0010] Step 3: Obtain the voltage data output by the hot-wire anemometer, and determine whether the voltage data is normal based on the identifier Bs, and remove abnormal data;

[0011] Step 4: Correct the voltage data obtained after removing abnormal data to obtain the corrected voltage data;

[0012] Step 5: Calculate the wind speed u based on the corrected voltage data;

[0013] Step 6: Determine the time interval td based on the preset sampling frequency fc, and combine it with the first wind speed measured by the two hot-wire probes. Second wind speed Calculate the velocity structure constant ;

[0014] Step 7: Calculate the second order turbulent dissipation rate and the third order turbulent dissipation rate ;

[0015] Step 8: Calculate the kinematic viscosity coefficient at the in-situ measurement position ;

[0016] Step 9: Calculate the inner scale of atmospheric turbulence ;

[0017] Step 10: Calculate the turbulence intensity I.

[0018] The power turbulent flow measurement method of the present application is also characterized in that:

[0019] Further, in the step 4, the voltage data obtained after removing the abnormal data is corrected by using the following formula (1) :

[0020] (1)

[0021] In formula (1), E1 is the output voltage of the hot-wire anemometer in the calibration state, and E2 is the output voltage of the hot-wire anemometer at the in-situ measurement position. is a correction coefficient related to the velocity, pressure and Reynolds number of the air flow; n is a parameter related to the Reynolds number at the in-situ measurement position, and m is a parameter related to the Reynolds number in the calibration state; v1 is the kinematic viscosity coefficient of the atmosphere in the calibration state; T w is the working temperature of the hot wire of the hot-wire anemometer; T1 is the temperature of the hot wire in the calibration state; T2 is the temperature of the hot wire at the in-situ measurement position; P1 is the atmospheric pressure at the position of the hot-wire anemometer in the calibration state; and P2 is the atmospheric pressure at the in-situ measurement position.

[0022] Further, in the step 5, the wind speed u is calculated according to the corrected voltage data by using the following formula (2) :

[0023] (2)

[0024] In formula (2), E is the output voltage value of the hot-wire anemometer, u is the wind speed corresponding to the output voltage value E, I w is the working current of the hot wire corresponding to the output voltage value E, R w is the working resistance of the hot wire corresponding to the output voltage value E, R f is the normal temperature resistance of the hot wire in the normal temperature state, and A and B are constants related to the length of the hot wire and the physical properties of the fluid.

[0025] Further, in the step 6, the velocity structure constant is calculated by using the following formula (3) : ;

[0026] ( 3)

[0027] In the formula (3), D uu (r) represents the second-order structure function of the vector r is the distance between two points in space to be measured; C is a dimensionless constant, usually 2; is the second-order turbulent dissipation rate of the atmosphere, which is calculated by the second-order structure function ; represents statistical average.

[0028] Further, in the step 7, the second-order turbulent dissipation rate is calculated by the following formula (4);

[0029] (4)

[0030] In the formula (4), C is a dimensionless constant, usually 2; is the velocity structure constant of the wind speed.

[0031] Further, in the step 7, the third-order turbulent dissipation rate is calculated by the following formula (5);

[0032] (5)

[0033] In the above formula (5), D represents the third-order structure function of the vector r is the distance between two points in space to be measured.

[0034] Further, in the step 8, the kinematic viscosity coefficient at the in-situ measurement position is calculated by the following formula (6);

[0035] (6)

[0036] In the above formula (6), C is the kinematic viscosity coefficient of the atmosphere in the calibration state; is the kinematic viscosity coefficient at the in-situ measurement position; T1 is the temperature of the hot wire in the calibration state; T2 is the temperature of the hot wire at the in-situ measurement position; P1 is the atmospheric pressure at the position of the hot-wire anemometer in the calibration state; and P2 is the atmospheric pressure at the in-situ measurement position.

[0037] Further, in the step 9, the inner scale of the atmospheric turbulence is calculated by the following formula (7);

[0038] ​​(7)

[0039] In the above formula (7), is the kinematic viscosity coefficient at the in-situ measurement position; is the third-order turbulent dissipation rate of the atmosphere.

[0040] Further, in the step 10, the turbulent intensity I is calculated by using the following formula (8):

[0041] (8)

[0042] In the above formula (8), is the root mean square of the turbulent fluctuation velocity within the time interval td (i.e., the standard deviation of the wind speed), is the average speed of the wind speed within the time interval td.

[0043] The application also provides a computer program product comprising a computer program; the computer program realizes the power turbulent flow measurement method described above when executed by a processor.

[0044] Compared with the prior art, the application has the beneficial effects of:

[0045] The application discloses a power turbulent flow measurement method, which comprises the following steps: measuring the wind speeds at two points in space by using a hot-wire anemometer with two hot-wire probes; setting the sampling frequency fc, the statistical average time ts and the space length r of the hot-wire anemometer; obtaining voltage data output by the hot-wire anemometer and determining whether the voltage data is normal, and eliminating abnormal data; obtaining corrected voltage data; calculating the wind speed u according to the corrected voltage data; determining the time interval td according to the pre-set sampling frequency fc, and calculating the velocity structure constant by combining the wind speeds measured by the two hot-wire probes; calculating the second-order and third-order turbulent dissipation rates; and sequentially calculating the kinematic viscosity coefficient at the in-situ measurement position, the inner scale of the atmospheric turbulent flow and the turbulent intensity I. The power turbulent flow measurement method of the application overcomes the shortcomings that the temperature fluctuation instrument cannot measure the power turbulent flow and the ultrasonic wind speed meter platform has poor applicability, and has the advantages of simple operation, applicability to severe environments, and applicability to high-altitude turbulent flow measurement by being carried on a sounding balloon.

[0046] BRIEF DESCRIPTION OF DRAWINGS

[0047] Fig. 1 It is a flow chart of the power turbulent flow measurement method of the application.

[0048] Fig. 2 It is a schematic view of the hot-wire anemometer with two hot-wire probes predicted by the power turbulent flow measurement method of the application.

[0049] ​The application will be further described in conjunction with the accompanying drawings through specific embodiments. DETAILED DESCRIPTION

[0050] Referring to Figs. 1-2 A power turbulent flow measuring method of the application mainly comprises the following steps:

[0051] Step 1: using a hot-wire anemometer with two hot-wire probes to measure the wind speed at two points in space;

[0052] The hot-wire anemometer of the application measures the wind speed by converting the flow speed signal into a voltage signal. A thin metal wire (also known as a hot wire, tungsten wire is used in the application) is placed in the airflow. The heat dissipation of the hot wire in the airflow is related to the flow speed. The heat dissipation causes the temperature of the hot wire to change, which leads to a change in resistance, thereby converting the flow speed signal into a voltage signal. The flow speed signal can be obtained by measuring the voltage signal, and thus the wind speed can be measured. In the application, each hot-wire probe corresponds to the wind speed at one of the two points in space. The two hot-wire probes are a first hot-wire probe and a second hot-wire probe. The two points in space corresponding to the first hot-wire probe and the second hot-wire probe are a first point in space and a second point in space.

[0053] The first hot-wire probe measures a first wind speed at the first point in space The second hot-wire probe measures a second wind speed at the second point in space Vectors Vectors are the position vectors of the first point in space and the second point in space, respectively, r is the distance between the measured first point in space and the second point in space, and is also the distance between the two hot-wire probes. r is usually taken as 1 m, i.e., the modulus of vector = 1. For example, Fig. 2 The left first probe is taken as the coordinate origin O, the vertical direction is taken as the Y axis, and the straight line pointing to the second probe and the straight line pointing to the left are taken as the X axis to establish a left-hand coordinate system. In this way, the coordinate of the first probe is (0, 0, 0), and the coordinate of the second probe is (r, 0, 0), which facilitates the calculation of vectors and coordinates.

[0054] Step 2: After arranging the hot-wire anemometer, set the sampling frequency fc, the statistical average time ts, and the spatial length r of the hot-wire anemometer;

[0055] Step 3: Obtain the voltage data output by the hot-wire anemometer, and determine whether the voltage data is normal according to the identifier Bs, and eliminate abnormal data; in the voltage data output by the hot-wire anemometer, except for the last bit of the voltage data, the other data is the voltage value, and the last bit of the voltage data is the identifier Bs. The identifier Bs is set by the hot-wire anemometer itself in the measurement program. When the detected voltage value is 0, the voltage data output contains the identifier Bs; it can be known from the identifier Bs that the voltage value of the voltage data is 0, indicating that the voltage data is invalid data. If the identifier Bs is not found in the voltage data, the voltage data is considered to be valid data.

[0056] Step 4: Correct the voltage data obtained after eliminating abnormal data to obtain corrected voltage data;

[0057] Step 5: Calculate the wind speed u according to the corrected voltage data;

[0058] Step 6: Determine the time interval td according to the pre-set sampling frequency fc, and combine the first wind speed and the second wind speed measured by the two hot-wire probes to calculate the velocity structure constant ;

[0059] In specific implementation, the time interval td is an integer k times of the sampling period 1 / fc, indicating that k measurements are performed within the time interval td, and a group of first wind speed and second wind speed are obtained at the first spatial point and the second spatial point in each measurement, and a total of k groups of first wind speed and second wind speed are obtained.

[0060] Step 7: Calculate the second-order turbulent dissipation rate and the third-order turbulent dissipation rate ;

[0061] Step 8: Calculate the kinematic viscosity coefficient at the in-situ measurement position ;

[0062] Step 9: Calculate the inner scale of atmospheric turbulence ;

[0063] Step 10: Calculate the turbulence intensity I.

[0064] As shown in FIG. 1, in the power turbulent flow measurement method of the present application, the first wind speed Fig. 1 and the second wind speed Fig. 2The hot-wire anemometer with two hot-wire probes is shown to measure the wind speed at two points in space, and then calculate the time series data of the wind speed. Then, under the precondition of assuming homogeneous isotropic turbulence, the wind speed at the two points is differentiated, and the speed structure constant of the wind speed is calculated by statistical calculation , real-time measurement of dynamic turbulence parameters, i.e. turbulence inner scale and turbulence intensity I.

[0065] In implementation, in step 4, the voltage data obtained after removing abnormal data is corrected by using the following formula (1);

[0066] (1)

[0067] In formula (1), E1 is the output voltage of the hot-wire anemometer in the calibration state, and E2 is the output voltage of the hot-wire anemometer in the in-situ measurement position; is a correction coefficient related to the speed, pressure and Reynolds number of the air flow; n is a parameter related to the Reynolds number at the in-situ measurement position, and m is a parameter related to the Reynolds number in the calibration state; v1 is the kinematic viscosity coefficient of the atmosphere in the calibration state; T w is the operating temperature of the hot wire of the hot-wire anemometer; T1 is the temperature of the hot wire in the calibration state; T2 is the temperature of the hot wire in the in-situ measurement position; P1 is the atmospheric pressure at the position of the hot-wire anemometer in the calibration state; and P2 is the atmospheric pressure at the in-situ measurement position.

[0068] In implementation, the voltage data of the two probes of the hot-wire anemometer is corrected separately, and the correction formula is the above formula (1), that is, the above formula (1) is applicable to any one of the two probes of the hot-wire anemometer. For example, T w is the operating temperature of the first hot-wire probe of the two probes in the measurement state, and other related parameters are also related parameters of the first hot-wire probe. When the voltage data of the second hot-wire probe is corrected, the corresponding related parameters of the second hot-wire probe are used in formula (1). The in-situ measurement position refers to the position of the current measurement point after the hot-wire anemometer determines the measurement position and is fixed.

[0069] In implementation, in step 5, the following formula (2) is used to calculate the wind speed u according to the corrected voltage data;

[0070] (2)

[0071] In formula (2), E is the output voltage value of the hot-wire anemometer, u is the wind speed corresponding to the output voltage value E, I w is the operating current of the hot wire corresponding to the output voltage value E, R w is the operating resistance of the hot wire corresponding to the output voltage value E, and R fA, B are constants related to the length of the hot wire and the physical properties of the fluid.

[0072] In the specific calculation, E is the output voltage value of any one of the two probes of the hot wire anemometer. Formula (2) is the same as formula (1), and can be applied to any one of the two probes of the hot wire anemometer. In the specific measurement, the working temperatures of the two probes are consistent. Ideally, the first hot wire probe and the second hot wire probe are two identical probes with two sets of circuits. The first hot wire probe measures the first wind speed at the first spatial point x, and the second hot wire probe measures the second wind speed at the second spatial point x+r. A, B are constants related to the length of the hot wire and the physical properties of the fluid. Through formula (2), a set of two data is obtained each time: the first wind speed and the second wind speed . The correction of the voltage data by formula (2) is mainly to correct the error caused by the large difference between the temperature and air pressure in the high-altitude environment and the laboratory calibration.

[0073] In the specific implementation, in step 6, the velocity structure constant is calculated by the following formula (3):

[0074] (3)

[0075] In formula (3), D uu (r) represents the second-order structure function of the vector , r is the distance between the two points in space to be measured; C is a dimensionless constant, usually taken as 2; is the second-order turbulent dissipation rate of the atmosphere, which is calculated by the second-order structure function ; represents statistical average.

[0076] In the specific implementation, the time interval td is an integer k times of the sampling period 1 / fc, indicating that k measurements are performed within the time interval td, and each measurement obtains a pair of wind speed values: the first wind speed and the second wind speed , a total of k pairs of the first wind speed and the second wind speed are obtained.

[0077] In the above formula (3), the statistical average is represented by , and the hot wire anemometer performs multiple measurements within the time interval td. Each measurement obtains a set of first wind speed and second wind speed , represents the second wind speed of any one set the square of the difference between the second wind speed and the first wind speed , and the average value of the multiple groups is obtained as . According to the multiple groups of wind speed measurement values within the time interval td, the velocity structure constant can be calculated according to formula (3) .

[0078] In specific implementation, in step 7, the second-order turbulent dissipation rate is calculated by formula (4) as follows:

[0079] (4)

[0080] In formula (4), C is a dimensionless constant, and is usually taken as 2; is the velocity structure constant of the wind speed.

[0081] The subscript 2 of indicates that the turbulent dissipation rate is calculated by the second-order structure function. According to the above formula (4), the velocity structure constant is substituted, and the second-order turbulent dissipation rate can be calculated in the case of determining the dimensionless constant C.

[0082] In specific implementation, in step 7, the third-order turbulent dissipation rate is calculated by formula (5) as follows:

[0083] (5)

[0084] In the above formula (5), the third-order structure function of the vector is represented, and r is the distance between two points measured in space.

[0085] The third-order turbulent dissipation rate of the atmosphere is calculated by the third-order structure function . The subscript 3 of indicates that the turbulent dissipation rate is calculated by the third-order structure function. The third-order structure function contains the cube of the difference between the second wind speed and the first wind speed .

[0086] In specific implementation, in step 8, the kinematic viscosity coefficient at the in-situ measurement position is calculated by formula (6) as follows:

[0087] (6)

[0088] In the above formula (6), the third-order turbulent dissipation rate The kinematic viscosity of the atmosphere under calibration conditions; T1 is the kinematic viscosity coefficient at the in-situ measurement location; T2 is the temperature of the hot wire under calibration conditions; P1 is the atmospheric pressure at the location of the hot wire anemometer under calibration conditions; and P2 is the atmospheric pressure at the in-situ measurement location.

[0089] In specific implementation, in step 9, the internal scale of atmospheric turbulence is calculated using the following formula (7). ;

[0090] (7)

[0091] In the above formula (7), This represents the kinematic viscosity coefficient at the in-situ measurement location. It represents the third-order turbulent dissipation rate of the atmosphere.

[0092] In specific implementation, in step 10, the turbulence intensity I is calculated using the following formula (8);

[0093] (8)

[0094] In the above formula (8), It is the root mean square of the turbulent fluctuation velocity within the time interval td (i.e., the standard deviation of the wind speed). It is the average wind speed within the time interval td.

[0095] and The results are calculated based on data measured by either of the two hot wire probes within the time interval td.

[0096] For example, the time interval td is an integer k multiple of the sampling period 1 / fc, indicating that k measurements were performed within the time interval td. Taking the first probe as an example, k first wind speeds were obtained within the time interval td. .but The calculation process is shown in the following formula (9).

[0097] (9)

[0098] In the above formula (9), k measurements were performed within the time interval td, and k first wind speeds were obtained. , is the k first wind speed The average value.

[0099] The calculation process is shown in the following formula (10).

[0100] (10)

[0101] In the above formula (10), k measurements are made in the time interval td, and k first wind speeds are obtained. The average of the k first wind speeds is obtained. The average of the squares of the differences between the k first wind speeds and the average of the k first wind speeds is obtained.

[0102] In actual implementation, since the distance between the first spatial point and the second spatial point is only 1 meter, for large-scale turbulent vortices greater than the distance between the two points, the velocities of the two points are consistent, and it can be considered that the turbulent intensity I calculated from the wind speed values obtained by the first spatial point and the second spatial point is basically the same. Therefore, only one set of first wind speeds or one set of second wind speeds is needed to calculate the turbulent intensity I. In fact, even if the two sets of wind speed values measured by the first spatial point and the second spatial point are different, the two turbulent intensities I finally calculated are basically the same.

[0103] The application also provides a computer program product, comprising a computer program; the computer program realizes the power turbulent flow measurement method described above when executed by a processor.

[0104] The above steps 1-10 are compiled into a measurement algorithm and embedded in the output program of the hot-wire anemometer, so that real-time measurement of power turbulent flow parameters can be performed.

[0105] As shown in Fig. 2 is a structural schematic diagram of the hot-wire anemometer used in the application. The hot-wire anemometer comprises a hot-wire anemometer host 4, and two support rods 3 are arranged at the top end of the hot-wire anemometer host 4. The two support rods 3 are in a V shape. The bottom of each support rod 3 is connected with the hot-wire anemometer host, and a metal bracket 2 is arranged at the top of each support rod 3. A thin metal wire is arranged at the top end of the metal bracket 2, and the thin metal wire used in the application is tungsten wire 1.

[0106] The power turbulent flow measurement method of the application uses a hot-wire anemometer with two hot-wire probes to measure the velocity time series data of two points in space. Under the assumption of uniform isotropic turbulence, the velocity structure constant is calculated after the velocities of the two points are differentiated, and the power turbulent flow parameters are measured in real time. The method of the application is simple to operate and can be observed for a long time without manual intervention; the method overcomes the shortcomings that the temperature fluctuation instrument cannot measure power turbulent flow and the ultrasonic anemometer platform has poor applicability, and provides a guarantee for long-term continuous acquisition of power turbulent flow parameters.

[0107] ​​In addition, the power turbulent flow measuring method can realize unmanned, long-time and real-time measurement of power turbulent flow parameters in harsh environments such as marine atmospheric environment, high-temperature and high-cold environment, and strong wind weather, and can be applied to high-altitude turbulent flow measurement by being carried on a sounding balloon.

[0108] The power turbulent flow measuring method is a new method for measuring power turbulent flow parameters in real time by using a hot-wire anemometer with two hot-wire probes.

[0109] In summary, the power turbulent flow measuring method overcomes the shortcomings of the temperature fluctuation instrument and the poor platform applicability of the ultrasonic anemometer, has the advantages of simple operation, application in harsh environments, and carrying on a sounding balloon for high-altitude turbulent flow measurement, and the like.

[0110] For those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0111] In addition, it should be understood that although the present application is described in the specification in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be properly combined to form other embodiments that those skilled in the art can understand.

Claims

1. A method for measuring dynamic turbulence, characterized in that, Includes the following steps: Step 1: Use a hot-wire anemometer with two hot-wire probes to measure the wind speed at two points in space; Step 2: After setting up the hot-wire anemometer, set the sampling frequency fc, statistical averaging time ts, and spatial length r of the hot-wire anemometer; Step 3: Obtain the voltage data output by the hot-wire anemometer, and determine whether the voltage data is normal based on the identifier Bs, and remove abnormal data; Step 4: Correct the voltage data obtained after removing abnormal data to obtain the corrected voltage data; Step 5: Calculate the wind speed u based on the corrected voltage data; Step 6: Determine the time interval td based on the preset sampling frequency fc, and combine it with the first wind speed measured by the two hot-wire probes. Second wind speed Calculate the velocity structure constant ; Step 7: Calculate the second-order turbulent dissipation rate and third-order turbulent dissipation rate ; Step 8: Calculate the kinematic viscosity coefficient at the in-situ measurement location. ; Step 9: Calculate the internal scale of atmospheric turbulence ; Step 10: Calculate the turbulence intensity I; Calculate the turbulence intensity I using the following formula (8); （8） In the above formula (8), It is the root mean square of the turbulent fluctuation velocity within the time interval td. It is the average wind speed within the time interval td.

2. The method for measuring dynamic turbulence according to claim 1, characterized in that, In step 4, the voltage data obtained after removing abnormal data is corrected using the following formula (1); （1） In formula (1), E1 is the output voltage of the hot-wire anemometer in the calibration state, and E2 is the output voltage of the hot-wire anemometer at the in-situ measurement point. The correction factor is related to the airflow velocity, pressure, and Reynolds number; n is a parameter related to the Reynolds number at the in-situ measurement location; m is a parameter related to the Reynolds number under calibration conditions; v1 is the kinematic viscosity coefficient of the atmosphere under calibration conditions; T w T1 is the operating temperature of the hot wire of the hot-wire anemometer; T2 is the temperature of the hot wire under calibration conditions; P1 is the temperature of the hot wire at the in-situ measurement location; P2 is the atmospheric pressure at the location of the hot-wire anemometer under calibration conditions; P2 is the atmospheric pressure at the in-situ measurement location.

3. The method for measuring dynamic turbulence according to claim 1, characterized in that, In step 5, the following formula (2) is used to calculate the wind speed u based on the corrected voltage data; （2） In formula (2), E is the output voltage value of the hot-wire anemometer, u is the wind speed corresponding to the output voltage value E, and I w R is the hot-wire operating current corresponding to the output voltage value E. w R is the hot-wire operating resistance corresponding to the output voltage value E. f Let A be the resistance of the hot wire at room temperature, and B be constants related to the length of the hot wire and the physical properties of the fluid.

4. The method for measuring dynamic turbulence according to claim 1, characterized in that, In step 6, the velocity structure constant is calculated using the following formula (3). ; （3） In formula (3), D uu (r) represents a vector The second-order structure function, r is the distance between two points in the measured space; C is a dimensionless constant, usually taken as 2; The second-order turbulent dissipation rate of the atmosphere indicates that this turbulent dissipation rate is achieved through the second-order structure function. Calculated; It represents the statistical average.

5. The method for measuring dynamic turbulence according to claim 1, characterized in that, In step 7, the second-order turbulent dissipation rate is calculated using the following formula (4). ; （4） In formula (4), C is a dimensionless constant, usually taken as 2; is the velocity structure constant for wind speed.

6. The method for measuring dynamic turbulence according to claim 5, characterized in that, In step 7, the third-order turbulent dissipation rate is calculated using the following formula (5). ; （5） In the above formula (5), Representing vectors The third-order structure function, where r is the distance between two points in the measured space.

7. The method for measuring dynamic turbulence according to claim 1, characterized in that, In step 8, the kinematic viscosity coefficient at the in-situ measurement location is calculated using the following formula (6). ; （6） In the above formula (6), The kinematic viscosity of the atmosphere under calibration conditions; T1 is the kinematic viscosity coefficient at the in-situ measurement location; T2 is the temperature of the hot wire under calibration conditions; P1 is the atmospheric pressure at the location of the hot wire anemometer under calibration conditions; and P2 is the atmospheric pressure at the in-situ measurement location.

8. The method for measuring dynamic turbulence according to claim 6, characterized in that, In step 9, the internal scale of atmospheric turbulence is calculated using the following formula (7). ; （7） In the above formula (7), This represents the kinematic viscosity coefficient at the in-situ measurement location. It represents the third-order turbulent dissipation rate of the atmosphere.

9. A computer program product comprising a computer program; characterized in that, When the computer program is executed by a processor, it implements the dynamic turbulence measurement method according to any one of claims 1-8.

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