Gust flow field calibration and characteristic analysis method based on swing blade type gust generator

Abstract

The invention discloses a gust flow field calibration and characteristic analysis method based on a swing blade type gust generator, and belongs to the technical field of low-speed wind tunnel non-uniform flow field calibration test. In order to intuitively analyze the influence rule of each characteristic parameter on the gust flow field characteristics, the method comprises the following steps: establishing a mathematical model of the gust flow field of the swing blade type gust generator; installing a swing blade type gust generator and a flow field calibration system; after the wind tunnel is started to a target wind speed, waiting for several seconds to be stable, controlling the swing blade type gust generator to enable the blades to swing according to a sinusoidal motion rule, and then triggering the hot-wire speed measurement system to perform lateral wind speed acquisition to obtain measurement data; calculating an attenuation coefficient of the gust flow field; for different measurement positions of the gust flow field, the attenuation coefficient of the gust flow field is calculated, and gust flow field calibration and characteristic analysis including gust flow field velocity analysis and gust flow field frequency analysis are carried out. The application efficiency of the gust wind tunnel test is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-speed wind tunnel non-uniform flow field calibration and testing, and in particular relates to a gust flow field calibration and characteristic analysis method based on a swing-blade gust generator. Background Art

[0002] Non-uniform flow simulation testing is a specialized dynamic wind tunnel testing technique. It primarily involves placing an airflow disturbance device at the entrance of a wind tunnel test section. After uniform incoming air flows through the device, a specific non-uniform flow field forms behind the test section, effectively simulating the complex non-uniform flow environment experienced by aircraft during flight. Gust flow, as a typical non-uniform flow field, is crucial for assessing the safety of aircraft in complex wind environments, and gust flow field calibration is a key technology. Currently, research on gust flow fields both domestically and internationally often relies on gust flow field calibration testing, employing a method that sequentially measures the flow field envelope at each state (e.g., wind speed, blade swing amplitude, and frequency). While this method offers the advantage of obtaining highly detailed gust flow field results, it also presents challenges such as high workload, long cycle times, low efficiency, and significant resource waste. Furthermore, gust flow field performance evaluation cannot be rapidly completed in the early stages of design. Furthermore, the relationship between gust flow field characteristics and generator parameters is often based solely on data fitting analysis, lacking a clear physical explanation. Summary of the Invention

[0003] The problem to be solved by the present invention is to intuitively analyze the influence of various characteristic parameters on the gust flow field characteristics, and propose a gust flow field calibration and characteristic analysis method based on a swing blade gust generator.

[0004] To achieve the above object, the present invention is implemented through the following technical solutions:

[0005] A gust flow field calibration and characteristic analysis method based on a swing-blade gust generator comprises the following steps:

[0006] S1. Establish a mathematical model of the gust flow field of a swing-blade gust generator;

[0007] S2. Install the swing-blade gust generator and flow field calibration system;

[0008] S3. After starting the wind tunnel to the target wind speed, wait a few seconds for it to stabilize. Then, control the swing-blade gust generator so that the blades swing in a sinusoidal motion. Then, trigger the hot-wire velocimetry system to collect lateral wind speed data.

[0009] S4 based on the measurement data obtained in step S3, calculate the attenuation coefficient of the gust flow field;

[0010] S5. For different measurement positions of the gust flow field, calculate the attenuation coefficient of the gust flow field based on the method of step S4, and perform gust flow field calibration and characteristic analysis, including gust flow field velocity analysis and gust flow field frequency analysis.

[0011] Furthermore, the specific implementation method of step S1 includes the following steps:

[0012] S1.1. Setting the Blade Angle of the Swinging Blade Gust Generator The expression is:

[0013]

[0014] in, is the blade swing angle amplitude, f is the swing frequency, and t is the time;

[0015] S1.2. Derivative the blade swing angle of the swing blade gust generator obtained in step S1.1 with respect to time t to obtain the swing angular velocity at the trailing edge of the blade: The expression is:

[0016] ;

[0017] Then calculate the blade trailing edge tangential velocity V1, the expression is:

[0018]

[0019] Wherein, L is the blade chord length;

[0020] S1.3. Based on the deflection of the incoming wind speed V0 after passing through the blade surface, the vertical velocity component V of the incoming wind speed is generated. 0y , the expression is:

[0021] ;

[0022] Calculate the velocity component V of the blade trailing edge tangential velocity V1 on the y-axis 1y The expression is:

[0023] ;

[0024] S1.4. The gust flow velocity at the trailing edge of the gust generator blade is obtained by summing the vertical velocity component of the incoming wind speed and the y-axis velocity component of the blade trailing edge tangential velocity V1. The expression is:

[0025] ;

[0026] Then, the gust velocity at any position of the gust generator is solved based on the gust flow field velocity at the trailing edge of the gust generator blade , the expression is:

[0027]

[0028] Where K is the attenuation coefficient of the gust flow field.

[0029] Furthermore, the swing-blade gust generator described in step S2 is arranged at the entrance of the wind tunnel test section, and the initial position of the blades in the swing-blade gust generator is defined as a position parallel to the horizontal plane of the wind tunnel, and this position is set as the flat plate zero position; the flow field calibration system is composed of a hot wire velocity measurement system and a mobile measurement frame, and the mobile measurement frame has a three-degree-of-freedom movement function. A two-dimensional hot wire probe is installed on the mobile measurement frame and is connected to the hot wire velocity measurement system, and the direction of the two-dimensional hot wire probe is adjusted to measure the lateral wind speed.

[0030] Furthermore, the specific implementation method of step S3 is to start the wind tunnel to the target wind speed and wait for a few seconds until it stabilizes, and control the gust generator to make the blade swing according to the sine motion law. The blade swing angle of the blade motion is , then trigger the hot wire speed measurement system to collect data, the collection frequency is 200Hz, the collection time is 20s, and the measurement data Data is obtained.

[0031] Furthermore, the specific implementation method of step S4 includes the following steps:

[0032] S4.1. Perform a fast Fourier transform on the measured data Data obtained in step S3 to obtain the dominant frequency F and the amplitude A of the data change, expressed as:

[0033]

[0034] in, and They are the maximum and minimum values of the measured data respectively;

[0035]

[0036]

[0037] in, is the maximum value function, is the minimum function;

[0038] S4.2. Calculate the gust velocity V at any location on the gust generator. y The amplitude A' is expressed as:

[0039] ;

[0040] S4.3. Based on the amplitude A of the data variation and the gust velocity V at any position of the gust generator y The amplitude is equal to A', so

[0041]

[0042] After sorting, the calculation formula of the attenuation coefficient of the gust flow field is:

[0043] .

[0044] Furthermore, the specific implementation method of step S5 includes the following steps:

[0045] S5.1. Move the two-dimensional hot wire probe measurement point and repeat steps S3 and S4 to obtain the gust flow field attenuation coefficient corresponding to different measurement positions;

[0046] S5.2. Set the gust speed The formula is expanded to get the expression:

[0047]

[0048] Then the derived identity is:

[0049]

[0050] in, is the function of gust speed changing with time;

[0051] S5.3. Based on the usage scenarios and engineering experience of the swing blade gust generator, when analyzing the gust flow field characteristics, the gust velocity in step S5.2 is Simplifying the formula, we get

[0052]

[0053] in, is the simplified gust speed;

[0054] Based on the above, we can get the gust amplitude and incoming wind speed and swing angle amplitude and oscillation frequency It is related to the blade angle, increases linearly with the increase of the incoming flow velocity, is positively correlated with the blade swing angle amplitude, and is less affected by the blade swing frequency. Based on the characteristic conclusions, engineering and technical personnel are guided to achieve rapid adjustment of the wind flow field.

[0055] Beneficial effects of the present invention:

[0056] The gust flow field calibration and characteristic analysis method based on the swing-blade gust generator described in the present invention starts from the gust flow field generation principle and is based on the generator blade motion equation to propose a gust flow field characteristic parameterized modeling method. Each part of the model has a clear physical meaning. Through this mathematical model, the influence of each characteristic parameter on the gust flow field characteristics can be intuitively seen, which helps designers to quickly estimate the gust flow field performance, efficiently complete the gust flow field calibration test, and effectively improve the application efficiency of gust wind tunnel tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a flow chart of the gust flow field calibration and characteristic analysis method based on the swing blade gust generator according to the present invention;

[0058] Figure 2 This is a schematic structural diagram of the swing blade gust generator according to the present invention;

[0059] Among them, 1 is the wind tunnel, 2 is the support frame, 3 is the drive motor, 4 is the blade connecting rod, and 5 is the blade. DETAILED DESCRIPTION

[0060] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. That is, the specific embodiments described herein are only some embodiments of the present invention, not all embodiments. Generally, the components of the specific embodiments of the present invention described and illustrated in the drawings herein can be arranged and designed in various different configurations, and the present invention can also have other embodiments.

[0061] Therefore, the following detailed description of the specific embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely representative of selected specific embodiments of the present invention. All other specific embodiments obtained by those skilled in the art based on the specific embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0062] In order to further understand the content, features and effects of the present invention, the following specific embodiments are given as examples, and the attached Figure 1 -Attached Figure 2 The detailed instructions are as follows:

[0063] Example 1:

[0064] A gust flow field calibration and characteristic analysis method based on a swing-blade gust generator comprises the following steps:

[0065] S1. Establish a mathematical model of the gust flow field of a swing-blade gust generator;

[0066] Furthermore, the specific implementation method of step S1 includes the following steps:

[0067] S1.1. Setting the Blade Angle of the Swinging Blade Gust Generator The expression is:

[0068]

[0069] in, is the blade swing angle amplitude, f is the swing frequency, and t is the time;

[0070] S1.2. Derivative the blade swing angle of the swing blade gust generator obtained in step S1.1 with respect to time t to obtain the swing angular velocity at the trailing edge of the blade: The expression is:

[0071] ;

[0072] Then calculate the blade trailing edge tangential velocity V1, the expression is:

[0073]

[0074] Wherein, L is the blade chord length;

[0075] S1.3. Based on the deflection of the incoming wind speed V0 after passing through the blade surface, the vertical velocity component V of the incoming wind speed is generated. 0y , the expression is:

[0076] ;

[0077] Calculate the velocity component V of the blade trailing edge tangential velocity V1 on the y-axis 1y The expression is:

[0078] ;

[0079] S1.4. The gust flow velocity at the trailing edge of the gust generator blade is obtained by summing the vertical velocity component of the incoming wind speed and the y-axis velocity component of the blade trailing edge tangential velocity V1. The expression is:

[0080] ;

[0081] Then, the gust velocity at any position of the gust generator is solved based on the gust flow field velocity at the trailing edge of the gust generator blade , the expression is:

[0082]

[0083] Where K is the attenuation coefficient of the gust flow field.

[0084] S2. Install the swing-blade gust generator and flow field calibration system;

[0085] Furthermore, the swing-blade gust generator described in step S2 is arranged at the entrance of the wind tunnel test section, and the initial position of the blades in the swing-blade gust generator is defined as a position parallel to the horizontal plane of the wind tunnel, and this position is set as the flat plate zero position; the flow field calibration system is composed of a hot wire velocity measurement system and a mobile measurement frame, the mobile measurement frame has a three-degree-of-freedom movement function, and a two-dimensional hot wire probe is installed on the mobile measurement frame and connected to the hot wire velocity measurement system, and the direction of the two-dimensional hot wire probe is adjusted to measure the lateral wind speed;

[0086] Furthermore, the swing-blade gust generator consists of two blades connected by a blade connecting rod, ensuring synchronous swing of the two blades. The swing amplitude and frequency of the blades are controlled by a drive motor, and the entire device is fixed to a support frame. The initial position of the blades in the generator is defined as parallel to the horizontal plane of the wind tunnel, and this position is set as the zero position of the plate. The flow field calibration system is located in the downstream test area of the wind tunnel test section.

[0087] S3. After starting the wind tunnel to the target wind speed, wait a few seconds for it to stabilize. Then, control the swing-blade gust generator so that the blades swing in a sinusoidal motion. Then, trigger the hot-wire velocimetry system to collect lateral wind speed data.

[0088] Furthermore, the specific implementation method of step S3 is to start the wind tunnel to the target wind speed and wait for a few seconds until it stabilizes, and control the gust generator to make the blade swing according to the sine motion law. The blade swing angle of the blade motion is , then trigger the hot wire speed measurement system to collect data, the collection frequency is 200Hz, the collection time is 20s, and the measurement data Data is obtained;

[0089] S4 based on the measurement data obtained in step S3, calculate the attenuation coefficient of the gust flow field;

[0090] Furthermore, the specific implementation method of step S4 includes the following steps:

[0091] S4.1. Perform a fast Fourier transform on the measured data Data obtained in step S3 to obtain the dominant frequency F and the amplitude A of the data change, expressed as:

[0092]

[0093] in, and They are the maximum and minimum values of the measured data respectively;

[0094]

[0095]

[0096] in, is the maximum value function, is the minimum function;

[0097] S4.2. Calculate the gust velocity V at any location on the gust generator. y The amplitude A' is expressed as:

[0098] ;

[0099] S4.3. Based on the amplitude A of the data variation and the gust velocity V at any position of the gust generator y The amplitude is equal to A', so

[0100]

[0101] After sorting, the calculation formula of the attenuation coefficient of the gust flow field is:

[0102] .

[0103] S5. For different measurement positions of the gust flow field, calculate the attenuation coefficient of the gust flow field based on the method of step S4, and perform gust flow field calibration and characteristic analysis, including gust flow field velocity analysis and gust flow field frequency analysis.

[0104] Furthermore, the specific implementation method of step S5 includes the following steps:

[0105] S5.1. Move the two-dimensional hot wire probe measurement point and repeat steps S3 and S4 to obtain the gust flow field attenuation coefficient corresponding to different measurement positions;

[0106] S5.2. Set the gust speed The formula is expanded to get the expression:

[0107]

[0108] Then the derived identity is:

[0109]

[0110] in, is the function of gust speed changing with time;

[0111] From the identity, we can know that the gust speed at any two moments with a time interval of 1 / f is the same. Based on the above, we can get that the gust flow field frequency is the same as the blade swing frequency;

[0112] S5.3. Based on the usage scenarios and engineering experience of the swing blade gust generator, when analyzing the gust flow field characteristics, the gust velocity in step S5.2 is Simplifying the formula, we get

[0113]

[0114] in, is the simplified gust speed;

[0115] Based on the above, we can get the gust amplitude and incoming wind speed and swing angle amplitude and oscillation frequency It is related to the blade angle, increases linearly with the increase of the incoming flow velocity, is positively correlated with the blade swing angle amplitude, and is less affected by the blade swing frequency. Based on the characteristic conclusions, engineering and technical personnel are guided to achieve rapid adjustment of the wind flow field.

[0116] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0117] Although the present application has been described above with reference to specific embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, as long as there are no structural conflicts, the various features of the embodiments disclosed herein may be combined with each other in any manner, and the omission of an exhaustive description of these combinations in this specification is solely for the sake of space and resource conservation. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

Claims

1. A gust flow field calibration and characteristic analysis method based on a swing blade gust generator, characterized in that: The steps include: S1. Establish a mathematical model of the gust flow field of a swing-blade gust generator; S2. Install the swing-blade gust generator and flow field calibration system; S3. After starting the wind tunnel to the target wind speed, wait a few seconds for it to stabilize. Then, control the swing-blade gust generator so that the blades swing in a sinusoidal motion. Then, trigger the hot-wire velocimetry system to collect lateral wind speed data. S4 based on the measurement data obtained in step S3, calculate the attenuation coefficient of the gust flow field; S5. For different measurement positions of the gust flow field, calculate the attenuation coefficient of the gust flow field based on the method of step S4, and perform gust flow field calibration and characteristic analysis, including gust flow field velocity analysis and gust flow field frequency analysis.

2. The method for gust flow field calibration and characteristic analysis based on a swing blade gust generator according to claim 1, characterized in that: The specific implementation method of step S1 includes the following steps: S1.

1. Setting the Blade Angle of the Swinging Blade Gust Generator The expression is: in, is the blade swing angle amplitude, f is the swing frequency, and t is the time; S1.

2. Derivative the blade swing angle of the swing blade gust generator obtained in step S1.1 with respect to time t to obtain the swing angular velocity at the trailing edge of the blade: The expression is: ； Then calculate the blade trailing edge tangential velocity V1, the expression is: Wherein, L is the blade chord length; S1.

3. Based on the deflection of the incoming wind speed V0 after passing through the blade surface, the vertical velocity component V of the incoming wind speed is generated. 0y , the expression is: ； Calculate the velocity component V of the blade trailing edge tangential velocity V1 on the y-axis 1y The expression is: ； S1.

4. The gust flow velocity at the trailing edge of the gust generator blade is obtained by summing the vertical velocity component of the incoming wind speed and the y-axis velocity component of the blade trailing edge tangential velocity V1. The expression is: ； Then, the gust velocity at any position of the gust generator is solved based on the gust flow field velocity at the trailing edge of the gust generator blade , the expression is: Where K is the attenuation coefficient of the gust flow field.

3. The method for gust flow field calibration and characteristic analysis based on a swing blade gust generator according to claim 2, characterized in that: The swing-blade gust generator described in step S2 is arranged at the entrance of the wind tunnel test section. The initial position of the blades in the swing-blade gust generator is defined as a position parallel to the horizontal plane of the wind tunnel, and this position is set as the flat plate zero position; the flow field calibration system consists of a hot wire velocity measurement system and a mobile measurement frame. The mobile measurement frame has a three-degree-of-freedom movement function. A two-dimensional hot wire probe is installed on the mobile measurement frame and is connected to the hot wire velocity measurement system. The direction of the two-dimensional hot wire probe is adjusted to measure the lateral wind speed.

4. The method for calibrating and analyzing gust flow fields based on a swing-blade gust generator according to claim 3, characterized in that: The specific implementation method of step S3 is to start the wind tunnel to the target wind speed and wait for a few seconds until it stabilizes, and then control the gust generator to make the blade swing according to the sine motion law. The blade swing angle of the blade motion is , then trigger the hot wire speed measurement system to collect data, the collection frequency is 200Hz, the collection time is 20s, and the measurement data Data is obtained.

5. The method for calibrating and analyzing gust flow fields based on a swing-blade gust generator according to claim 4, characterized in that: The specific implementation method of step S4 includes the following steps: S4.

1. Perform a fast Fourier transform on the measured data Data obtained in step S3 to obtain the dominant frequency F and the amplitude A of the data change, expressed as: in, and They are the maximum and minimum values of the measured data respectively; in, is the maximum value function, is the minimum function; S4.

2. Calculate the gust velocity V at any location on the gust generator. y The amplitude A' is expressed as: ； S4.

3. Based on the amplitude A of the data variation and the gust velocity V at any position of the gust generator y The amplitude is equal to A', so After sorting, the calculation formula of the attenuation coefficient of the gust flow field is: 。 6. The method for gust flow field calibration and characteristic analysis based on a swing blade gust generator according to claim 5, characterized in that: The specific implementation method of step S5 includes the following steps: S5.

1. Move the two-dimensional hot wire probe measurement point and repeat steps S3 and S4 to obtain the gust flow field attenuation coefficient corresponding to different measurement positions; S5.

2. Set the gust speed The formula is expanded to get the expression: Then the derived identity is: in, is the function of gust speed changing with time; S5.

3. Based on the usage scenarios and engineering experience of the swing blade gust generator, when analyzing the gust flow field characteristics, the gust velocity in step S5.2 is Simplifying the formula, we get in, is the simplified gust speed; Based on the above, we can get the gust amplitude and incoming wind speed and swing angle amplitude and oscillation frequency It is related to the blade angle, increases linearly with the increase of the incoming flow velocity, is positively correlated with the blade swing angle amplitude, and is less affected by the blade swing frequency. Based on the characteristic conclusions, engineering and technical personnel are guided to achieve rapid adjustment of the wind flow field.

Images