Cavitation form real-time sensing and identification experiment system and method considering attitude disturbance

Abstract

The invention discloses a cavitation bubble form real-time sensing and identification experiment system and method considering attitude disturbance. The system comprises an experiment model and an auxiliary device thereof, a pressure sensor, an inertia unit, a servo motor, a gas flowmeter, a high-speed camera, an upper computer, a signal conditioner, a data acquisition instrument and a trigger. The method comprises the following steps: calculating a difference value between pressure information obtained by a bubble external pressure measuring point and pressure information obtained by a cavitation bubble internal pressure measuring point, and taking the difference value as a cavitation bubble internal and external pressure difference reference value in an initial state; the upper computer controls the servo motor to do periodic pitching motion; determining the target length of the cavitation bubble; calculating the pressure change, caused by the pitching motion, of different pressure measuring points compared with the cavitation internal and external pressure difference reference value in the initial state, and determining the length of the identified cavitation; comparing the difference between the identified vacuole length and the target vacuole length, and adjusting the ventilatory capacity to enable the identified vacuole length to be consistent with the target vacuole length; and the upper computer updates an angular velocity instruction, iteratively measures, and traverses all cavitation lengths needing to be measured.

Description

Technical Field

[0001] This invention relates to an experimental system and method for real-time sensing and identification of cavitation morphology considering attitude disturbances, belonging to the field of fluid machinery engineering technology. Background Technology

[0002] Ventilation control of underwater experimental models is a pressing engineering problem involving solid-liquid-gas three-phase coupling. To enable underwater experimental models to adapt to complex sea conditions, ventilated cavitation has been widely used as an important method to effectively improve the hydrodynamic characteristics of experimental models. Ventilated cavitation is a highly complex flow phenomenon involving multiphase flow, turbulence, mass transport, compressibility, and unsteady flow mechanisms. In particular, the application of ventilated cavitation technology has greatly improved the motion stability of underwater experimental models. When the experimental model moves underwater, the shoulder and most of the middle area of ​​the model are enclosed by ventilated cavitation, with only the tail and head areas in contact with the water. This concentrates the hydrodynamic force on the experimental model in a defined area, greatly increasing the stability of the underwater motion. However, during actual movement, due to continuous changes in environmental conditions such as pressure and incoming flow velocity, the morphology of the ventilated cavitation is significantly disturbed, causing drastic changes in the hydrodynamic environment of the experimental model, affecting the stability of the experimental model's motion, and even causing the experimental model to fail. Therefore, some scholars have proposed an adaptive intelligent ventilation control experimental method and device, providing a control method and solution for the change in ventilation bubble length caused by environmental factors. However, the experimental model undergoes large pitching motions during the experiment, causing significant changes in surface pressure, which leads to the failure of the sensing law for ventilation bubble length, resulting in the inability to control the bubble length.

[0003] Therefore, it is of great significance to fully understand the impact of different pitch motion states on the hydrodynamic environment and cavitation development of the experimental model through experimental research, to reveal the real-time matching mechanism between changes in the hydrodynamic environment and cavitation morphology, and to realize the adaptability of the experimental model to harsher environments.

[0004] Currently, the sensing of ventilated cavitation length in experimental models relies on the measurement of surface pressure. Based on a certain number of pressure sensors, the pressure difference inside and outside the ventilated cavitation is used to sense and measure its length. When the experimental model's attitude and speed are constant, the pressure difference inside and outside the ventilated cavitation is relatively stable and can be considered a constant. However, when the experimental model's attitude and speed change significantly, the pressure inside and outside the ventilated cavitation changes significantly, rendering the constant pressure difference-based cavitation length criterion ineffective. This leads to misjudgment or failure to sense the cavitation length, resulting in inaccurate control of the cavitation length and a loss of effective control over the experimental model's motion and hydrodynamic environment. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide an experimental system and method for real-time perception and identification of cavitation morphology considering attitude disturbances. This solves the problem that existing methods based on direct interpretation of pressure measurement results are difficult to achieve cavitation length perception and real-time control, and provides technical approaches and methodological support for improving the performance of underwater experimental models.

[0006] The technical solution of this invention is:

[0007] Firstly, an experimental system for real-time perception and identification of cavitation morphology considering attitude perturbations is provided, including:

[0008] The experimental model and its auxiliary devices include a pressure sensor, inertial unit, servo motor, gas flow meter, high-speed camera, dysprosium lamp, host computer, signal conditioner, data acquisition instrument, and trigger; among which:

[0009] The experimental model is a rotating body, connected to the output of a servo motor via an external rotating shaft; the experimental model is equipped with an internal ventilation pipe.

[0010] A pressure sensor is installed on the surface of the experimental model to measure the surface pressure of the experimental model;

[0011] A gas flow meter is connected to the ventilation pipe inside the experimental model to measure the flow parameters of the experimental model.

[0012] An inertial unit is installed on the experimental model to measure the pitch angle and pitch rate of the experimental model;

[0013] The pressure sensor, gas flow meter, and inertial unit simultaneously send the measured data to the signal conditioner. The signal conditioner preprocesses the received data and then sends it to the data acquisition unit. The data acquisition unit sends the collected pressure data, flow parameters, pitch angle and pitch velocity information to the host computer for storage and display.

[0014] The PLC controller is connected to the servo motor. The PLC controller controls the rotation angle and angular velocity of the servo motor, and transmits the rotation angle and angular velocity feedback from the servo motor to the host computer for display and storage. At the same time, the host computer outputs servo motor action commands to the PLC controller to control the rotation angle and angular velocity of the servo motor.

[0015] The experimental system is also equipped with two dysprosium lamps as light sources for the experimental flow field; two high-speed cameras are controlled by the host computer through triggers, so that the data acquisition instrument and the two high-speed cameras are triggered synchronously to record the flow field cavitation image photos obtained by the high-speed cameras, realizing the synchronous acquisition of pressure data, gas flow parameters, pitch angle and pitch velocity of the experimental model, and rotation angle and rotation velocity of the servo motor.

[0016] Preferably, the auxiliary devices for the experimental model include: a water tunnel panel, a hydrodynamic rudder, a support platform, and a limiter; wherein:

[0017] The hydrodynamic rudder is installed at the tail of the experimental model to simulate the working state of a real rudder surface;

[0018] The water tunnel panel is made of metal and is fixed to the water tunnel experimental platform by pressing on all four sides; the water tunnel panel has mounting holes for the rotating shaft to pass through and connect the experimental model and the servo motor.

[0019] The support platform is fixed perpendicularly to the water tunnel panel at the lower end of the mounting holes on the water tunnel panel, and is used to fix the servo motor and limiters; the limiters are used to limit the rotation angle range of the experimental model and the rotating shaft.

[0020] Preferably, multiple pressure sensors are symmetrically arranged on the surface of the experimental model, with the installation positions being pressure measuring points. The spacing between adjacent measuring points is the same, and the position information of each pressure measuring point is recorded.

[0021] Secondly, this paper provides an experimental method for real-time perception and identification of cavitation morphology considering attitude perturbations, including...

[0022] S1 connects to the experimental system and provides the initial state of the experimental system;

[0023] S2 measures the surface pressure of the experimental model, the rotation angle and angular velocity of the experimental model, and cavitation image information;

[0024] S3 calculates the difference between the pressure information obtained from the pressure measurement point outside the bubble and the pressure information obtained from the pressure measurement point inside the bubble based on the bubble image information and surface pressure information obtained by the high-speed camera, and uses this difference as the reference value of the pressure difference between the inside and outside of the bubble in the initial state.

[0025] The S4 host computer sends angular velocity commands to control the servo motor to perform periodic pitching motion at a certain angular velocity;

[0026] S5 determines the target length of the cavitation bubble based on the given pitch motion parameters of the experimental model; it calculates the pressure changes at different pressure measurement points caused by the pitch motion compared to the reference value of the pressure difference between the inside and outside of the cavitation bubble in the initial state, and determines the identified cavitation bubble length.

[0027] S6 compares the difference between the identified cavitation length and the target cavitation length, adjusts the ventilation volume to make the identified cavitation length consistent with the target cavitation length, and achieves cavitation length stability under the rotational motion conditions of the experimental model;

[0028] The S7 host computer updates the angular velocity command, returns to step S4, iterates the measurement, traverses all the cavitation lengths that need to be measured, and then ends the experiment; and outputs the surface pressure data, gas flow parameters, pitch angle and pitch velocity of the experimental model, rotation angle and rotation velocity of the servo motor, as well as the target length of the cavitation and the identified cavitation length during the experiment.

[0029] Preferably, in S1, the initial state of the experimental model is:

[0030] The experimental model remained stable. The host computer sent an initial ventilation signal to the water tunnel experimental platform, and ventilation was introduced into the water tunnel experimental platform through the ventilation pipe inside the experimental model, forming ventilation cavitation on the surface of the experimental model. At this time, the length of the cavitation was relatively stable, and only the tail of the cavitation occurred unsteadily.

[0031] Preferably, in S5, the pressure changes at different pressure measuring points caused by the pitch motion are as follows:

[0032] δP 1,i =0.5*ρ*(ωL) i ) 2

[0033] Where ρ is the density of water, ω is the angular velocity of the pitch motion of the experimental model, i represents the index of the pressure measurement point, and L... i Let be the distance from the i-th pressure measurement point to the center of rotation of the experimental model;

[0034] Corrected cavitation length identification parameter δP 2,i for:

[0035] δP 2,i =δP0+δP 1,i+1 -δP 1,i

[0036] δP0 is the reference value for the pressure difference between the inside and outside of the cavitation bubble in the initial state.

[0037] Preferably, in S5, when determining the cavitation length, the specific steps are as follows:

[0038] Let P i X represents the measurement result of the i-th pressure measuring point. i This represents the vertical distance between the installation location of the i-th pressure sensor and the vertex of the cone segment of the experimental model;

[0039] When the pitch angular velocity is less than or equal to 0, the pressure measurement points on the upper surface of the experimental model are used as a reference for judging the cavitation length, and the upper surface is selected to satisfy P. i+1 -P i >δP 2,i For the pressure measuring point, assuming the cavitation length lies between measuring point i and i+1, then the cavitation length L c =[Xi ,X i+1 ];

[0040] When the pitch angular velocity is greater than 0, the pressure measurement points on the lower surface of the experimental model are used as a reference for judging the cavitation length, and the upper surface is selected to satisfy P. i+1 -P i >δP 2,i For the pressure measurement point, if the cavitation length is considered to be between measurement point i and i+1, then the cavitation length L is identified. c =[X i ,X i+1 ].

[0041] Preferably, in S6, the ventilation rate is adjusted so that the identified cavitation length matches the target cavitation length, specifically as follows:

[0042] If the identified cavitation length is greater than the target cavitation length L ct That is, min(L) c )>L ct Then, the ventilation volume is reduced using a ventilation flow meter;

[0043] If the identified cavitation length is less than the target cavitation length L ct That is, max(L) c ) <L ct Then increase ventilation.

[0044] If the identified cavitation length includes the target cavitation length L ct L ct ∈L c If the ventilation rate remains constant, then the ventilation rate will remain unchanged.

[0045] Preferably, periodic pitch motion can be replaced by unidirectional motion with a constant angular velocity or unidirectional motion with acceleration at a certain angle.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] (1) This invention discloses a water tunnel experimental device that can realize the attitude stability control of the experimental model, which can realize the experimental model to move or be fixed at a certain angle according to a certain pitch angular velocity and angular acceleration;

[0048] (2) This invention discloses a real-time cavitation morphology sensing method that considers the attitude disturbance of the experimental model, which can improve the cavitation identification effect when the experimental model is in pitch motion.

[0049] (3) This invention discloses a real-time control experimental system and method for cavitation length considering the attitude disturbance of the experimental model, which can carry out the ventilated cavitation length sensing and closed-loop control experiment when the experimental model is pitching in a vertical state. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the water tunnel experimental device for sensing and controlling the length of the ventilated cavitation bubble considering the pitch motion of the experimental model, as described in this invention.

[0051] Figure 2 This is a schematic diagram of the layout of the experimental system for real-time control of cavitation morphology considering attitude disturbances of the experimental model, as presented in this invention. Detailed Implementation

[0052] This scheme adds a rotation axis to the experimental model, based on the pressure measuring points on the surface of the experimental model. This axis can control the pitch motion of the experimental model in real time and feed back the pressure information and pitch motion information to the controller in real time. The controller corrects the cavitation length identification parameters based on the pitch motion information to achieve accurate identification of the cavitation length. The controller adjusts the ventilation volume based on the cavitation length identification result to achieve cavitation length control.

[0053] I. Experimental setup as follows Figure 1 As shown, the water tunnel experimental device for achieving stable attitude control of the experimental model includes: a water tunnel panel, a rotating shaft, an experimental model, a hydrodynamic rudder, a support platform, limit switches, and a servo motor, wherein:

[0054] The water tunnel panel is a high-strength metal panel, fixed to the water tunnel experimental platform by pressing together all four sides. The water tunnel panel is designed with mounting holes for fixing the support platform. The support platform is perpendicular to the water tunnel panel, and one end is fixed to the water tunnel panel with screws. The rotating shaft and the support platform are connected by screws. The rotating shaft passes through the circular mounting holes in the water tunnel panel and is rigidly connected to the experimental model and the servo motor, enabling the experimental model to rotate. The hydrodynamic rudder is fixed to the tail of the experimental model. The limiter is fixed to the support platform to limit the rotation angle range of the experimental model and the rotating shaft. The servo motor is fixed to the support platform.

[0055] Considering the attitude perturbation of the experimental model, the cavitation length real-time control experimental system is as follows: Figure 2 As shown, the experimental system includes a pressure sensor, inertial unit, servo motor, gas flow meter, high-speed camera, dysprosium lamp, computer, signal conditioner, data acquisition unit, trigger, etc., among which:

[0056] The pressure sensor is installed on the surface of the experimental model. The pressure sensor used is a probe-type dynamic pressure sensor with a diameter of 5mm. The pressure sensor is connected to the signal conditioner via an aviation plug. The signal conditioner is connected to the data acquisition instrument via a data cable. The data acquisition instrument is connected to computer 3 via a network cable. The pressure data measured by the pressure sensor on the experimental model can be transmitted to computer 3 for display and storage.

[0057] The experimental model contains a ventilation tube connected to a gas flow meter. The flow rate within the ventilation tube can be adjusted via the flow meter. The flow meter is connected to a signal conditioner via a data cable, allowing the flow rate parameters fed back from the flow meter to be transmitted to computer 3 for display and storage. An inertial unit is installed on the experimental model to measure its pitch angle and pitch velocity. The inertial unit is also connected to the signal conditioner via a data cable, allowing the pitch angle and pitch velocity information obtained by the inertial unit to be fed back to computer 3 for display and recording. A servo motor is connected to a PLC controller via a cable, enabling... The PLC controller controls the rotation angle and angular velocity of the servo motor. The PLC controller is connected to PC3 via a data cable, allowing the servo motor's feedback rotation angle and angular velocity to be transmitted to PC3 for display and storage. PC3 can also output commands for the servo motor's rotation angle and angular velocity to the PLC controller, thus controlling the servo motor's rotation angle and angular velocity. Two dysprosium lamps are also used as light sources for the experimental flow field. Two high-speed cameras are connected to PC1 and PC2 via network cables, allowing the recording of flow field images obtained from the high-speed cameras through PC1 and PC2. Triggers are connected to PC1, PC2, and the data acquisition unit via data cables, enabling synchronous triggering of the data acquisition unit and the two high-speed cameras. This allows for the synchronous acquisition of pressure data, gas flow parameters, experimental model rotation angle and angular velocity, and servo motor rotation angle and angular velocity.

[0058] II. The specific steps of the real-time cavitation morphology sensing method considering the attitude perturbation of the experimental model are as follows:

[0059] 1. Given the initial state of the experimental model and the initial ventilation signal.

[0060] According to such Figure 2 The schematic diagram shows the setup of the experimental equipment, with a given inflow velocity from the water tunnel. A controller is used to keep the motor stationary (vertically or stably) of the experimental model. An initial ventilation signal is then given to create ventilation bubbles. At this point, the bubble length is relatively stable, with unsteady shedding only occurring at the tail of the bubble.

[0061] 2. Measurement of experimental data

[0062] A computer-generated trigger signal activates a pressure sensor, inertial unit, and high-speed camera to collect real-time data on the surface pressure of the experimental model, its rotation angle and angular velocity, and cavitation images. The pressure sensor measurement points are as follows: Figure 2 As shown, a total of 18 pressure sensors were symmetrically placed on the upper and lower surfaces of the experimental model, with a spacing of 15 mm between the sensors and the first sensor being 60 mm from the top of the model.

[0063] 3. Calculate cavitation length to identify initial parameters

[0064] Based on the cavitation image information and surface pressure information obtained by the high-speed camera, the pressure information obtained by the pressure measuring point outside the cavitation and the pressure information obtained by the pressure measuring point inside the cavitation are calculated. This difference is used as the reference value of the pressure difference between the inside and outside of the cavitation under this state, δP0.

[0065] 4. Use servo motors to change the motion state of the model.

[0066] The computer 3 provides the rotational angular velocity of the experimental model, and the servo motor drives the experimental model to perform periodic pitching motion at a certain angular velocity ω.

[0067] 5. Correct the cavitation length identification parameter to identify the cavitation length L. c

[0068] Using the cavitation length based on the given pitch motion parameters of the experimental model, the pressure change δP at different pressure measuring points caused by the pitch motion is calculated. 1,i =0.5*ρ*(ωL) i ) 2 Where ρ is the density of water, ω is the angular velocity of the experimental model, and L... i Let be the distance from the i-th pressure measurement point to the center of rotation. Obtain the corrected cavitation length identification parameter δP. 2,i =δP0+δP 1,i+1 -δP 1,i The pressure measurement points on the surface of the experimental model are traversed, and the pressure information difference between adjacent measurement points is compared. Depending on the angular velocity of the experimental model, the following two cases exist:

[0069] (a) When the pitch angular velocity is less than or equal to 0 (clockwise rotation or stationary), the pressure measurement points on the upper surface of the experimental model are used as a reference for judging the cavitation length, and the upper surface is selected to satisfy P. i+1 -P i >δP 2,i For the pressure measuring point, the cavitation length can be considered to be between measuring point i and i+1, then the cavitation length L c =[X i ,X i+1 ]; P i X represents the measurement result of the i-th pressure measuring point; i Let be the vertical distance between the installation position of the i-th pressure sensor and the vertex of the cone segment of the experimental model.

[0070] (b) When the pitch angular velocity is greater than 0 (counterclockwise rotation), the pressure measurement point on the lower surface of the experimental model is used as a reference for judging the cavitation length, and the upper surface is selected to satisfy P. i+1 -P i >δP 2,i For the pressure measuring point, the cavitation length can be considered to be between measuring point i and i+1, then the cavitation length L can be identified. c =[Xi ,X i+1 ].

[0071] 6. Incorporate the cavitation length identification into the control loop to adjust the ventilation rate.

[0072] The control loop compares the difference between the identified cavitation length and the target cavitation length, and adjusts the ventilation volume to make the identified cavitation length consistent with the target cavitation length, thereby stabilizing the cavitation length under the rotational motion conditions of the experimental model.

[0073] The identified cavitation length is incorporated into the control loop, along with the target cavitation length L. ct In comparison, there are three possible scenarios:

[0074] (a) If the identified cavitation length is greater than the target cavitation length [min(L)] c )>L ct If the ventilation rate is reduced, a ventilation flow meter can be used to decrease the ventilation volume.

[0075] (b) If the identified cavitation length is less than the target cavitation length, increase the ventilation rate [max(L c ) <L ct ];

[0076] (c) If the identified cavitation length includes the target cavitation length (L) ct ∈L c If the target cavitation length falls within this range, the ventilation rate will remain constant.

[0077] 7. After the ventilation rate changes, the cavitation length changes. Return to step 5.

[0078] Based on the ventilation rate in step 6, the cavitation length on the experimental model surface will evolve with time and model state (rotation angle and angular velocity). At this point, return to step 5 to identify the new cavitation length L. c Repeat steps 5 and 6 until the experimental results are obtained.

[0079] The motion states of the experimental model include, but are not limited to, periodic reciprocating motion, unidirectional motion at a certain angular velocity, and unidirectional motion with a certain angular acceleration.

[0080] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. An experimental system for real-time sensing and identification of cavitation morphology considering attitude perturbations, characterized in that... include: The experimental model and its auxiliary devices include a pressure sensor, inertial unit, servo motor, gas flow meter, high-speed camera, dysprosium lamp, host computer, signal conditioner, data acquisition instrument, and trigger; among which: The experimental model is a rotating body, connected to the output of a servo motor via an external rotating shaft; the experimental model is equipped with an internal ventilation pipe. A pressure sensor is installed on the surface of the experimental model to measure the surface pressure of the experimental model; A gas flow meter is connected to the ventilation pipe inside the experimental model to measure the flow parameters of the experimental model. An inertial unit is installed on the experimental model to measure the pitch angle and pitch rate of the experimental model; The pressure sensor, gas flow meter, and inertial unit simultaneously send the measured data to the signal conditioner. The signal conditioner preprocesses the received data and then sends it to the data acquisition unit. The data acquisition unit sends the collected pressure data, flow parameters, pitch angle and pitch velocity information to the host computer for storage and display. The PLC controller is connected to the servo motor. The PLC controller controls the rotation angle and angular velocity of the servo motor, and transmits the rotation angle and angular velocity feedback from the servo motor to the host computer for display and storage. At the same time, the host computer outputs servo motor action commands to the PLC controller to control the rotation angle and angular velocity of the servo motor. The experimental system is equipped with two dysprosium lamps as the light source for the experimental flow field; two high-speed cameras are controlled by the host computer through triggers, so that the data acquisition instrument and the two high-speed cameras are triggered synchronously to record the flow field cavitation image photos obtained by the high-speed cameras, realizing the synchronous acquisition of pressure data, gas flow parameters, pitch angle and pitch velocity of the experimental model, and rotation angle and rotation velocity of the servo motor.

2. The experimental system for real-time sensing and identification of cavitation morphology considering attitude perturbation according to claim 1, characterized in that: The auxiliary devices for the experimental model include: a water tunnel panel, a hydrodynamic rudder, a support platform, and limiters; among which: The hydrodynamic rudder is installed at the tail of the experimental model to simulate the working state of a real rudder surface; The water tunnel panel is made of metal and is fixed to the water tunnel experimental platform by pressing on all four sides; the water tunnel panel has mounting holes for the rotating shaft to pass through and connect the experimental model and the servo motor. The support platform is fixed perpendicularly to the water tunnel panel at the lower end of the mounting holes on the water tunnel panel, and is used to fix the servo motor and limiters; the limiters are used to limit the rotation angle range of the experimental model and the rotating shaft.

3. The experimental system for real-time sensing and identification of cavitation morphology considering attitude perturbation according to claim 1, characterized in that: Multiple pressure sensors are symmetrically arranged on the surface of the experimental model, and the installation positions are pressure measurement points.

4. A real-time sensing and identification experimental method for cavitation morphology considering attitude perturbations using the experimental system described in claim 1, characterized in that... include: S1 connects to the experimental system and provides the initial state of the experimental system; S2 measures the surface pressure of the experimental model, the rotation angle and angular velocity of the experimental model, and cavitation image information; S3 calculates the difference between the pressure information obtained from the pressure measurement point outside the bubble and the pressure information obtained from the pressure measurement point inside the bubble based on the bubble image information and surface pressure information obtained by the high-speed camera, and uses this difference as the reference value of the pressure difference between the inside and outside of the bubble in the initial state. The S4 host computer sends angular velocity commands to control the servo motor to perform periodic pitching motion at a certain angular velocity; S5 determines the target length of the cavitation bubble based on the given pitch motion parameters of the experimental model; it calculates the pressure changes at different pressure measurement points caused by the pitch motion compared to the reference value of the pressure difference between the inside and outside of the cavitation bubble in the initial state, and determines the identified cavitation bubble length. S6 compares the difference between the identified cavitation length and the target cavitation length, adjusts the ventilation volume to make the identified cavitation length consistent with the target cavitation length, and achieves cavitation length stability under the rotational motion conditions of the experimental model; The S7 host computer updates the angular velocity command, returns to step S4, iterates the measurement, traverses all the cavitation lengths that need to be measured, and then ends the experiment; and outputs the surface pressure data, gas flow parameters, pitch angle and pitch velocity of the experimental model, rotation angle and rotation velocity of the servo motor, as well as the target length of the cavitation and the identified cavitation length during the experiment.

5. The experimental method for real-time sensing and identification of cavitation morphology considering attitude perturbation according to claim 4, characterized in that: In S1, the initial state of the experimental model is: The experimental model remained stable. The host computer sent an initial ventilation signal to the water tunnel experimental platform, and ventilation was introduced into the water tunnel experimental platform through the ventilation pipe inside the experimental model, forming ventilation cavitation on the surface of the experimental model. At this time, the length of the cavitation was relatively stable, and only the tail of the cavitation occurred unsteadily.

6. The experimental method for real-time sensing and identification of cavitation morphology considering attitude perturbation according to claim 4, characterized in that: In S5, the pressure changes at different pressure measuring points caused by the pitch motion are as follows: δP 1,i =0.5*ρ*(ωL i ) 2 Where ρ is the density of water, ω is the angular velocity of the pitch motion of the experimental model, i represents the index of the pressure measurement point, and L... i Let be the distance from the i-th pressure measurement point to the center of rotation of the experimental model; Corrected cavitation length identification parameter δP 2,i for: δP 2,i =δP0+δP 1,i+1 -δP 1,i δP0 is the reference value for the pressure difference between the inside and outside of the cavitation bubble in the initial state.

7. The experimental method for real-time sensing and identification of cavitation morphology considering attitude perturbation according to claim 6, characterized in that: In S5, the determination of the cavitation length is specifically as follows: Let P i X represents the measurement result of the i-th pressure measuring point. i This represents the vertical distance between the installation location of the i-th pressure sensor and the vertex of the cone segment of the experimental model; When the pitch angular velocity is less than or equal to 0, the pressure measurement points on the upper surface of the experimental model are used as a reference for judging the cavitation length, and the upper surface is selected to satisfy P. i+1 -P i >δP 2,i For the pressure measuring point, assuming the cavitation length lies between measuring point i and i+1, then the cavitation length L c =[X i ,X i+1 ]; When the pitch angular velocity is greater than 0, the pressure measurement points on the lower surface of the experimental model are used as a reference for judging the cavitation length, and the upper surface is selected to satisfy P. i+1 -P i >δP 2,i For the pressure measurement point, if the cavitation length is considered to be between measurement point i and i+1, then the cavitation length L is identified. c =[X i ,X i+1 ].

8. The experimental method for real-time sensing and identification of cavitation morphology considering attitude perturbation according to claim 7, characterized in that: In S6, the ventilation volume is adjusted to make the identified cavitation length match the target cavitation length, specifically: If the identified cavitation length is greater than the target cavitation length L ct That is, min(L) c )>L ct Then, the ventilation volume is reduced using a ventilation flow meter; If the identified cavitation length is less than the target cavitation length L ct That is, max(L) c ) <L ct Then increase ventilation. If the identified cavitation length includes the target cavitation length L ct L ct ∈L c If the ventilation rate remains constant, then the ventilation rate will remain unchanged.

9. The experimental method for real-time sensing and identification of cavitation morphology considering attitude perturbation according to claim 4, characterized in that: Periodic pitching motion can be replaced by unidirectional motion with a constant angular velocity or unidirectional motion with acceleration at a certain angle.

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