A device and method for measuring sediment transport parameters under indoor flume ice cover flow conditions

Abstract

The application discloses a device and method for measuring sediment transport parameters under the ice cover flow condition of an indoor water tank, which adopts a streamline design of a submerged platform and application of non-contact / remote measurement technology (such as ADCP, sonar and laser), significantly reduces disturbance to a complex flow field under the ice cover, ensures authenticity of a measurement environment, and synchronously obtains all-round parameters such as hydraulics, sediment, boundaries and sediment transport rate through integrated design of the submerged measurement platform in one-time measurement; the median diameter and characteristic diameter of the sediment are accurately calculated through particle image analysis technology, measurement data are calculated in a multi-data combination mode, reliability of the data is ensured, accuracy of the data is ensured through data checking, the data are mobile collected and integrated, quick collection of the data is facilitated and errors caused by manual participation are reduced, consistency of the data in time and space is ensured, and reliability of parameter correlation analysis is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and river ice hydraulic testing technology, specifically to a device and method for measuring sediment transport parameters under indoor flume ice cover flow conditions. Background Technology

[0002] In cold-region rivers, the formation of ice sheets significantly alters the hydraulic and sediment transport characteristics. The presence of ice sheets transforms the flow from open channel flow to closed or semi-closed ice sheet flow, resulting in complex changes in velocity profiles, boundary shear stress distribution, and sediment initiation and transport patterns. Accurately determining sediment transport parameters under ice sheet flow conditions is crucial for predicting river channel evolution during glacial periods, reservoir operation, water conservancy project safety, and ecological environmental protection.

[0003] Traditionally, measurements under ice caps are conducted using bedload or suspended sediment samplers, a method that is extremely space-constrained and difficult to operate. Furthermore, instrument placement can interfere with the already complex flow field beneath the ice cap, affecting the accuracy of measurements, particularly influencing velocity distribution and sediment initiation states in ways that are difficult to assess. This has a significant impact on fine-grained sediment beds in a critical initiation state, leading to data distortion.

[0004] Secondly, key boundary parameters such as the surface roughness of the ice sheet, the effective water depth (distance from the bottom of the ice sheet to the bed surface), and the slope of the water surface under the ice sheet (energy slope) are difficult to obtain directly and accurately. For example, the water surface slope cannot be directly observed due to the ice cover, and it is usually estimated by drilling ice holes upstream and downstream to measure the water level, which is inefficient and damages the integrity of the ice sheet.

[0005] Therefore, there is an urgent need for an integrated technology and device that can overcome the above-mentioned defects and achieve multi-parameter synchronous, non-contact or low-interference, high-precision dynamic measurement under ice sheet flow conditions. Summary of the Invention

[0006] The purpose of this invention is to provide a device and method for measuring sand transport parameters under indoor water tank ice cap flow conditions, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for determining sediment transport parameters under indoor water tank ice cap flow conditions, comprising:

[0008] Step 1: Pre-measurement preparation. Place the submersible measurement platform, which carries the Doppler current profiler, side-scan sonar, laser scanner, pressure sensor, underwater camera system, control and data integration unit and automatic water sampler, in the water tank and establish a communication connection with the shore-based data processing center. Place the simulated ice sheet above the water body, and then continuously inject test water into the water tank.

[0009] Step 2: Device calibration and initial positioning. Zero-point calibration is performed on the pressure sensors on the submersible measurement platform. The standard scale calibration plate is photographed using an underwater camera system to complete the image scale calibration. The initial precise position of the platform is determined by combining GPS and an underwater acoustic positioning system.

[0010] Step 3: Dynamic Synchronous Measurement

[0011] The submersible measurement platform is controlled to move at a constant speed along the water tank track. During the movement, water samples are collected from the cross section using an automatic water sampler. Simultaneously, the measurement equipment on the submersible measurement platform is activated to obtain cross section test data.

[0012] Step 4: Data Integration and Processing: All data streams collected in Step 3 are transmitted in real time to the control and data integration unit. The control and data integration unit then integrates the data and transmits it to the shore-based data processing center for further processing.

[0013] Step 5: Result Output and Verification

[0014] By integrating all processed parameters, a comprehensive sediment transport parameter dataset for the section where the submersible measurement platform is located is generated. The calculated suspended sediment concentration is compared and verified with the suspended sediment concentration obtained through water sample analysis to evaluate the measurement accuracy.

[0015] Preferably, in step one, the Doppler current profiler has a measurement blind zone of ≤3cm and a profile resolution of ≥1cm; the underwater camera system is equipped with a camera and an auxiliary light source to acquire images of riverbed sediment particles in order to analyze the sediment particle size distribution and bed morphology.

[0016] Preferably, in step three, the vertical and lateral velocity profile data of the flow field are continuously acquired using a Doppler velocity profiler.

[0017] The topography of the ice sheet underside was continuously scanned using side-scan sonar.

[0018] The water depth in the tank was measured using a laser scanner;

[0019] Pressure data at both ends of the submersible measurement platform are collected using pressure sensors, and the pressure values ​​at both ends are continuously recorded.

[0020] Acquire images of the bed surface at fixed points or continuously using an underwater camera system;

[0021] When the submersible measurement platform travels to different positions within the water tank, it triggers an automatic water sampler to collect water samples at key locations.

[0022] Preferably, in step four, the shore-based data processing center processes the data acquired by the Doppler current profiler, side-scan sonar, laser scanner, pressure sensor, and underwater camera system.

[0023] 1) Calculate the water surface slope J based on the pressure difference and platform travel distance collected by the micro pressure sensor array, combined with fluid dynamics formulas;

[0024] 2) Integrate flow velocity data, effective water depth data, and real-time water temperature data to calculate the cross-sectional average flow velocity U and Reynolds number. R e and Froude's number F r Isohydraulic parameters;

[0025] 3) Filter and extract features from the data acquired by the side-scan sonar, and calculate the equivalent sand grain roughness height on the lower surface of the ice sheet. k s Grayscale processing and particle identification were performed on the bed surface images to analyze the characteristics of sediment particle size distribution, riverbed roughness coefficient, and bed surface morphology parameters.

[0026] 4) Based on the bed surface images obtained by the underwater camera system, the median particle size of the sediment is calculated using particle image analysis technology. d 50 Characteristic particle size d 10 , d 90 ;

[0027] 5) Based on the cross-sectional water velocity, suspended sediment concentration, and sediment characteristic parameters measured by the Doppler current profiler and camera system, calculate the suspended sediment transport rate based on these parameters. bedload transport rate and total sediment transport;

[0028] 6) Concentration of suspended solids in water samples obtained through laboratory analysis sampling devices. ;

[0029] 7) After completing all data acquisition and calculation, integrate all parameters such as ice sheet roughness, riverbed roughness, and water temperature obtained from the Doppler current profiler to generate a comprehensive data report.

[0030] An indoor flume ice cap flow condition sediment transport parameter measuring device is used to implement an indoor flume ice cap flow condition sediment transport parameter measuring method, comprising:

[0031] The main body of the water tank used to simulate the water flow environment is covered with test sand at the bottom. It has an adjustable flow rate water pump and a water outlet at both ends. One side of the main body of the water tank is connected to the output end of the water pump through the water inlet on it. The input end of the water pump is connected to the water storage tank. The water storage tank is connected to the other side of the main body of the water tank through a water pipe, so that the main body of the water tank, the water pump and the water storage tank form a circulation.

[0032] A water sampling device, including a sampling tube, is used to collect water samples from the main body of the water tank at different times;

[0033] The submersible measurement platform is equipped with a first sliding plate, which is slidably connected to a first slide rail on the inner wall of the tank body. The submersible measurement platform is equipped with a Doppler current profiler, a side-scan sonar, a laser scanner, a pressure sensor, a camera, and a sampler. The submersible measurement platform can adjust the spatial position of the above components relative to the tank body to adapt to different measurement ranges. The submersible measurement platform can also adjust the sampling position of the sampler.

[0034] The control and data integration unit, encapsulated inside the submersible measurement platform, includes a waterproof processor, a storage module, and a wireless transmission module. It is used to control the collaborative work between various sensors, synchronously collect data, and transmit the data to the shore-based data processing center in real time.

[0035] The shore-based data processing center receives data streams from the control and data integration unit and performs subsequent data processing.

[0036] Preferably, the submersible measurement platform further includes a first drive motor fixedly mounted on its lower surface, with mounting brackets fixedly connected to both ends of the first drive motor. The mounting brackets are fixedly connected to a mounting rod for mounting a thruster, and a thruster for moving the submersible measurement platform is provided on the mounting rod.

[0037] The water sampling device also includes sampling tubes fixedly mounted on the sampler. The sampler is fixed on the submersible measurement platform. There are four sampling tubes, which are arranged equidistantly in a circle on the sampler. A sampling cover plate is provided on the upper surface of the sampler. The sampling cover plate is rotatably mounted on the submersible measurement platform. The sampling cover plate is provided with a notch corresponding to the sampling tube. The notch ensures that water enters the sampling tube. The lower surface of the sampling cover plate is fixedly connected to the output shaft of the second drive motor.

[0038] Preferably, the Doppler current profiler is fixedly mounted on the upper surface of the submersible measurement platform, the side-scan sonar is fixedly mounted on one side of the upper surface of the submersible measurement platform, the laser scanner is located on the side of the submersible measurement platform, the pressure sensor is fixedly mounted at both ends of the submersible measurement platform, and the camera is fixedly mounted on the lower surface of the submersible measurement platform.

[0039] Preferably, an incandescent lamp is provided on one side of the camera, and the incandescent lamp is fixedly installed on the lower surface of the submersible measurement platform.

[0040] Compared with the prior art, the beneficial effects of the present invention are:

[0041] The streamlined design of the submersible platform and the application of non-contact / long-distance measurement technology in this device significantly reduce disturbance to the complex flow field under the ice sheet, ensuring the authenticity of the measurement environment, and making the determination of the critical conditions for sediment initiation more accurate.

[0042] This device, through the integrated design of a submersible measurement platform, can simultaneously acquire comprehensive parameters such as hydraulics, sediment, boundary conditions, and sediment transport rate in a single measurement. It accurately calculates the median and characteristic particle sizes of sediment using particle image analysis technology, and employs a multi-data combination approach to ensure data reliability. Data verification further guarantees accuracy. The mobile submersible measurement platform integrates mobile data acquisition and water sample collection, facilitating rapid data collection and reducing errors caused by human intervention. This ensures data consistency across time and space and significantly improves the reliability of parameter correlation analysis.

[0043] This device directly quantifies ice sheet roughness using side-scan sonar, accurately measures effective water depth using a laser scanner, and indirectly calculates water surface slope with high precision using a pressure sensor array, overcoming the bottleneck of difficulty in accurately obtaining these parameters in traditional methods. Attached Figure Description

[0044] Figure 1 This is a flowchart of a method for determining sand transport parameters under indoor water tank ice cap flow conditions according to the present invention;

[0045] Figure 2 This is a schematic diagram of the main circulation system of the indoor water tank for measuring sand transport parameters under ice cap flow conditions, according to the present invention.

[0046] Figure 3 This is a schematic diagram of the installation position of the submersible measuring platform of the indoor water tank ice cap flow condition sand transport parameter measuring device of the present invention;

[0047] Figure 4 This is a schematic diagram of the main structure of the submersible measurement platform of the indoor water tank ice cap flow condition sand transport parameter measuring device of the present invention;

[0048] Figure 5 This is a schematic diagram of the thruster structure, close-up camera lens, and incandescent lamp position of a submersible measuring platform for measuring sand transport parameters under indoor water tank ice cap flow conditions, according to the present invention.

[0049] Figure 6This is a schematic diagram of the water sample collection device of the indoor water tank ice cap flow condition sediment transport parameter measurement device of the present invention;

[0050] Figure 7 This is a schematic diagram of the main body of the water tank and the roughness of the ice cover in the sand transport parameter measuring device under the ice cover flow condition of the present invention.

[0051] In the diagram: 1. Water tank body; 101. Water inlet; 102. Water storage tank; 2. Water pump; 3. Water inlet pipe; 4. Submersible measurement platform; 406. Mounting platform; 407. Doppler current profiler; 408. Side-scan sonar; 409. Laser scanner; 410. Camera; 411. Incandescent lamp; 412. First drive motor; 413. Mounting bracket; 415. Mounting rod; 416. Thruster; 417. First sliding plate; 419. Pressure sensor; 5. Simulated ice cover; 6. First slide rail; 7. Water outlet; 801. Sampler; 802. Empty sampling tube; 803. Sampling cover plate; 804. Second drive motor. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] Please see Figure 1 This invention proposes a method for measuring sediment transport parameters under indoor flume ice cap flow conditions, which is implemented using the indoor flume ice cap flow condition sediment transport parameter measuring device constructed below:

[0054] Step 1: Pre-measurement Preparation: This step aims to construct a stable and controllable ice sheet flow test environment and complete the deployment and debugging of the measurement system. Specifically, it includes two core components: water circulation construction and measurement platform deployment.

[0055] 1. Deployment and communication establishment of the measurement platform: The submersible measurement platform 4, which integrates a Doppler current profiler 407, a side-scan sonar 408, a laser scanner 409, a pressure sensor array 419, an underwater camera system (including a camera 410 and an incandescent lamp 411), and a control and data integration unit, is placed in the preset initial position inside the main body of the tank 1. After the platform installation is completed, the shore-based data processing center is started, and a two-way communication link between the measurement platform and the shore-based data processing center is established through wired or wireless communication modules to ensure real-time transmission of measurement data and effective issuance of control commands.

[0056] 2. Construction of circulating water body and simulation of ice cover: A layer of test sand is laid in the main body of the water tank 1 and leveled manually. The water pump 2 is started to continuously inject test water from the water storage tank 102 into the main body of the water tank 1 through the water inlet 101 until the water depth reaches the test design value. The simulated ice cover 5 made of paraffin or foam material is covered on the surface of the water body. The planar dimensions of the simulated ice cover 5 match the cross-sectional dimensions of the main body of the water tank 1, and its lower surface is treated by a preset process to form a roughness equivalent to the lower surface of the natural ice cover, so as to accurately simulate the boundary effect of the ice cover 5 on the water flow.

[0057] After the ice cover is installed, keep the water pump 2 running and open the outlet 7 on the other side of the water tank body 1 to build a closed water circulation system: the water in the water tank body 1 flows back to the water storage tank 102 through the outlet 7, and is then pressurized by the water pump 2 and reinjected into the water tank body 1 to ensure the water flow in the water tank is stable.

[0058] Specifically, in this embodiment, to test the sand transport parameters under indoor water tank ice cap flow conditions, model ice caps with different roughness were made using polystyrene foam boards and paraffin blocks, such as... Figure 7 As shown, no paraffin blocks are placed on the polystyrene foam board to simulate a smooth ice sheet. The denser the spacing between the paraffin blocks on the polystyrene foam board, the rougher the ice sheet.

[0059] Step Two: Device Calibration and Initial Positioning. This step aims to eliminate measurement system errors and ensure the accuracy of measurement data. It specifically includes two stages: sensor calibration and platform positioning.

[0060] 1. Sensor calibration: Zero-point calibration of the pressure sensor 419 array mounted on the submersible measurement platform 4; image scale calibration is completed by taking pictures of the standard scale calibration plate through the underwater camera system.

[0061] 2. Initial positioning: The initial position of the submersible measurement platform 4 is accurately measured using a graduated steel tape measure.

[0062] Step 3: Dynamic synchronous measurement. Control the submersible measurement platform 4 to move along the water tank track at a constant low speed. During the movement, all measurement components are activated synchronously to achieve dynamic synchronous acquisition of multiple parameters.

[0063] 1. The movement control of the submersible measurement platform 4: In the initial state, two thrusters 416 are symmetrically arranged at the tail end of the submersible measurement platform 4. When the thrusters 416 are started, the platform is driven to move along the length of the water tank towards the outlet 7 (i.e., the end of the water tank) through thrust. When the platform reaches the preset position at the end of the water tank, the thrusters 416 are stopped and the first drive motor 412 is started. The output shaft of the first drive motor 412 drives the mounting frame 413 to rotate 180° around the output shaft axis. The mounting frame 413 synchronously drives the mounting rod 415 and the thrusters 416 fixedly connected to it to rotate, so that the thrusters 416 switch from the tail end to the fore end of the platform. The thrusters 416 are restarted, driving the platform to move back towards the inlet 101. Through the coordinated action of the first drive motor 412, the mounting frame 413 and the mounting rod 415, the fore and aft positions of the thrusters 416 can be quickly switched. The platform can complete the reciprocating movement without manual intervention, which greatly improves the measurement efficiency and avoids the interference of manual operation on the water flow state.

[0064] 2. Multi-parameter synchronous acquisition: During the platform's movement, each measuring component operates synchronously at a preset frequency. The specific acquired cross-sectional parameters and technical specifications are as follows:

[0065] Doppler current profiler 407: It acquires the vertical and lateral velocity distribution of the flow field under the ice sheet at a measurement frequency of not less than 2MHz. Its measurement blind zone is ≤3cm and the profile resolution is ≥1cm, ensuring that high-precision velocity data can be obtained in the near-ice sheet area (upper part of the water body) and the near-bed area (lower part of the water body).

[0066] Side-scan sonar 408: Scans the lower surface of the simulated ice sheet 5 and quantifies the roughness parameters of the lower surface of the ice sheet through echo signal analysis;

[0067] Laser Scanner 409: Real-time measurement of the vertical distance from the lower surface of the ice sheet to the riverbed, accurately obtaining effective water depth data;

[0068] Pressure sensor 419 array: synchronously collects water pressure data at the front and rear of the platform, and calculates the water surface slope (energy slope J) by combining the platform's travel distance.

[0069] Underwater camera system: A stable light source is provided by an incandescent lamp 411, and a camera 410 continuously captures images of the riverbed surface to obtain images of sediment particles for subsequent particle size distribution and bed morphology analysis.

[0070] 3. Simultaneous water sampling: During the platform's movement, water samples are collected simultaneously from different cross-sections using sampling devices for laboratory analysis of suspended solids concentration. It is used to calibrate indirect measurement results.

[0071] The specific operation is as follows: Start the second drive motor 804 of the sampling device. The second drive motor 804 drives the sampling cover plate 803 to rotate around the output shaft axis of the second drive motor 804. When the notch on the sampling cover plate 803 coincides with the opening of the sampling empty tube 802, the water flows into the sampling empty tube 802 through the notch to complete a single sampling. As the platform continues to move and the second drive motor 804 rotates at a constant speed, the notch of the sampling cover plate 803 coincides with the openings of the other three sampling empty tubes 802 in sequence, realizing the continuous collection of water samples from four different cross sections.

[0072] Step 4: Data integration and processing. All data streams collected in Step 3 are integrated through the control and data integration unit and transmitted in real time to the shore-based data processing center. The data processing software within the center performs the following calculations and analyses. The data processing software is equipped with a three-dimensional gas-liquid-solid multiphase flow field synchronous measurement system.

[0073] The calculation and analysis process of the three-dimensional gas-liquid-solid multiphase flow field synchronous measurement system deployed at the shore-based data processing center for the data collected in this experiment is as follows:

[0074] 1. Based on the pressure difference collected by the array of miniature pressure sensors 419 and the platform's travel distance, the water surface slope (energy slope) J is calculated using fluid dynamics formulas. The water surface slope J is the ratio of the water surface elevation difference to the horizontal distance, and the difference in water depth between two adjacent miniature pressure sensors 419 is equal to the difference in water surface elevation. Given that the horizontal distance L between the two pressure sensors 419 is known, the water surface slope can be calculated as follows: In the formula, The pressure difference between the two sensors, The density of water, This is the acceleration due to gravity.

[0075] 2. Integrate flow velocity data, effective water depth data, and real-time water temperature data to calculate the cross-sectional average flow velocity U and Reynolds number. R e and Froude's number F r Isohydraulic parameters:

[0076] The cross-sectional average velocity U is the ratio of the flow rate to the cross-sectional area of ​​the water passage.

[0077] 3. Filter and extract features from the data acquired by the side-scan sonar 408 to extract the equivalent sand grain roughness height of the lower surface of the ice sheet. k s (Used to characterize ice sheet roughness), the specific extraction method is as follows:

[0078] The raw echo intensity signal and distance data acquired by the high-frequency side-scan sonar 408 are subjected to mean filtering or median filtering in sequence to remove random pulse noise and interference from water flow and bubbles.

[0079] Bandpass filtering preserves the effective echo frequency band of the lower surface of the ice sheet while filtering out low-frequency background drift and high-frequency environmental noise.

[0080] Distance correction and sound velocity compensation eliminate ranging errors caused by changes in the sound velocity in the water, resulting in a high-order sequence of the ice sheet's lower surface along the scanning direction. ,in To scan the lateral distance, This represents the vertical undulation of the lower surface of the ice sheet relative to the average elevation.

[0081] High-order sequence of the lower surface of the ice sheet after correction Extracting local elevation deviations: (in the formula) This is the local moving average elevation; (Height of local roughness undulations on the lower surface of the ice sheet), and then obtained through... Calculate the root mean square roughness of the lower surface of the ice sheet : , (in the formula) (This refers to the effective scanning length of a single side-scan sonar line of 408). Finally, based on the classical roughness theory of wall turbulence, the root mean square roughness of the lower surface of the ice sheet is calculated. Converted to equivalent sand grain roughness height k s : , (in the formula, The roughness conversion factor (determined through ice sheet model calibration tests, typically ranging from 4.0 to 6.0) was obtained through multiple scans along the length of the water tank. k s The sequence is spatially interpolated to generate the equivalent sand grain roughness height distribution across the entire field on the lower surface of the ice sheet, which is then used for subsequent calculations of ice sheet flow boundary conditions and analysis of sediment transport models.

[0082] 4. Based on the bed surface images obtained by the underwater camera system, the median particle size of the sediment is calculated using particle image analysis technology. d 50 Characteristic particle size d 10 , d 90 The surface morphology and riverbed roughness are obtained through surface images;

[0083] Median particle size in particle image analysis techniques d 50 It represents the overall average size level of sediment particles and is the most commonly used particle size characteristic parameter; d10 It represents the control particle size of fine particles in sediment, reflecting the lower limit size of fine particles; d 90 The upper limit control particle size representing coarse particles in the sediment reflects the constraint on the maximum size of coarse particles. After obtaining the above three sediment particle size characteristic parameters through particle image analysis technology, for the same type of sediment (with similar particle true density and shape) and under the same compaction state in this embodiment, the uniformity of particle gradation is the core factor affecting porosity.

[0084] The method for obtaining the characteristic particle size of sediment through particle image analysis is as follows:

[0085] 1) Perform grayscale conversion, threshold segmentation, and edge detection on the images obtained by the camera system to remove background noise and water reflections, thereby achieving accurate separation of sediment particles from the water background;

[0086] 2) Statistical analysis of pixel features (single particle pixel area) of all effective suspended particles in the image. Total pixel area );

[0087] 3) In the known , Under the premise of, through Calculate the actual equivalent particle size of a single sediment particle (where: Let be the actual equivalent spherical particle size of the i-th sediment particle; For the first The pixel area of ​​each particle; (This is the scale conversion factor.)

[0088] 4) Sort all particles by equivalent particle size from smallest to largest and calculate the cumulative particle size distribution; based on the cumulative volume distribution, obtain the characteristic particle sizes corresponding to the cumulative frequencies of 10%, 50%, and 90% through linear interpolation, which are respectively the characteristic particle sizes. d 10 Median particle size d 50 Characteristic particle size d 90 .

[0089] 5. Based on the cross-sectional water velocity and sediment characteristics measured by the Doppler current profiler 407 and the camera system, the suspended sediment concentration (i.e., sediment concentration) in the cross-sectional water body is calculated. Boundary shear stress Parameters, based on the above parameters, calculate the suspended sediment transport rate. bedload transport rate And total sediment transport:

[0090] Shear stress at the mud-sand boundary (That is, the critical shear stress at which sediment begins to move), which can be calculated using the Shields formula: In the formula, Shields number (0.03 for uniform sand) This refers to the density of sediment particles;

[0091] Suspended sediment concentration (i.e., sediment concentration) The calculation process for ) is as follows:

[0092] 1) In the known Under the premise of, through Calculate the actual volume of a single sediment particle.

[0093] 2) In the known Under the premise of, through Calculate suspended concentration (In the formula: The effective number of particles in the image. (The actual water volume corresponding to the effective observation area of ​​the image)

[0094] The shear stress at the sediment boundary calculated above. Suspended concentration Calculate suspended sediment transport rate bedload transport rate And total sediment transport:

[0095] 1) Suspended sediment transport rate This refers to the mass of suspended sediment passing through a cross-section of water per unit time, given the known sediment concentration in the water body at that cross-section. The suspended sediment transport rate is obtained under the following conditions: In the formula, The density of sediment particles, Flow rate at cross-section;

[0096] 2) Bedload transport rate It is the mass of bedload sediment passing through the cross section per unit time, given the width of the flume. (Effective sediment transport width of the cross-section), median particle size of sediment d 50 Calculate the bedload transport rate under the premise of: In the formula, For gravitational acceleration (9.8) ), The average shear stress of the water flow ( , The hydraulic radius is used in calculating the Reynolds number. R e Time has been obtained. (Water surface slope).

[0097] 3) Total sediment transport is the sum of suspended sediment transport rate and bedload transport rate, representing the total mass of sediment passing through the cross section per unit time.

[0098] 6. The concentration of suspended solids in water samples obtained by analyzing the sampling device using the weighing-drying method in the laboratory. .

[0099] 7. After completing all data acquisition and calculation, integrate all parameters such as ice sheet roughness, riverbed roughness, and water temperature obtained by the Doppler current profiler 407 to generate a comprehensive data report.

[0100] Step 5: Result Output and Verification. Integrate all parameters obtained in Step 4 to generate a comprehensive sediment transport parameter dataset under specific hydraulic conditions, using the sampler 801 sampling section, the camera system, and the Doppler current profiler 407 operating section (both on the same section). Calculate the suspended sediment concentration... Suspended sediment concentration obtained from laboratory water sample analysis Compare the results and calculate the relative error.

[0101] Please see Figure 2-7 This embodiment proposes an indoor water tank sediment transport parameter measuring device under ice cap flow conditions to realize the above-mentioned indoor water tank sediment transport parameter measuring method under ice cap flow conditions. It includes a water tank body 1, which is a hollow cuboid made of transparent tempered glass. The transparent glass allows observation of the sediment flow within the water tank body 1, ensuring smooth and transparent sidewalls. The inner surface and bottom of the water tank body 1 are flat for laying the sediment to be tested. An inlet 101 is fixedly installed on one side of the water tank body 1, and the inlet 101 is fixedly connected to the output end of a water pump 2 via an inlet pipe 3. The inlet of the water pump 2 is connected to a water storage tank 102. The water pump 2 is a conventional model water pump, which allows water from the water storage tank 102 to be injected into the water tank body 1 through the inlet 101. An outlet 7 is fixedly connected to the other side of the water tank body 1, and the outlet 7 is connected to the water storage tank 102 (shown in...). Figure 2 ).

[0102] An electromagnetic flow meter is fixedly connected to the output end of the water pump 2. The electromagnetic flow meter is an existing technology component. By setting this technology component, the water output of the water pump 2 can be statistically analyzed. The water pump 2 adopts an existing variable frequency water pump with adjustable water output. The variable frequency water pump can control the amount and speed of water injected into the water tank body 1.

[0103] To enable the movement of the submersible measurement platform 4 and its components as described below, a first slide rail 6 is fixedly installed in the middle of the inner wall of each of the two long sides of the water tank body 1. One end of a first slide plate 417 is slidably installed on each first slide rail 6, and the other end of the first slide plate 417 is fixedly connected to the side of the submersible measurement platform 4. The submersible measurement platform 4 slides on the first slide rail 6 via the first slide plate 417 under the action of the thruster 416 described below.

[0104] The submersible measurement platform 4 adopts a streamlined design to reduce disturbance to the water flow inside the main body of the water tank 1.

[0105] The submersible measurement platform 4 also includes a first drive motor 412 fixedly mounted on its lower surface. The first drive motor 412 is an existing dual-output shaft motor. A waterproof shell is provided on the outer surface of the first drive motor 412 for waterproofing. The output shafts at both ends of the first drive motor 412 are fixedly connected to one end of a mounting bracket 413. The other end of the mounting bracket 413 is fixedly connected to one end of a mounting rod 415. Two thrusters 416 are mounted on the mounting rod 415. The thrusters 416 are existing brushless electric thrusters. The travel speed of the brushless electric thrusters can be precisely controlled within the range of 0-1.5 m / s to adapt to different flow velocity conditions (shown in...). Figure 5 ).

[0106] In the initial state, the two thrusters 416 are located at the tail end of the submersible measurement platform 4. By setting the two thrusters 416, the submersible measurement platform 4 can be driven forward in the water. After the submersible measurement platform 4 moves from the water inlet 101 end of the water tank body 1 to the other end under the action of the thrusters 416, the first drive motor 412 is started. The first drive motor 412 drives the mounting bracket 413, which is fixedly connected to its output shaft, to rotate. When the mounting bracket 413 rotates, it drives the mounting rod 415 and the thrusters 416, which are fixedly connected to it, to rotate together. The mounting frame 413 rotates in one step, with the rotation center of the mounting frame 413 being the output shaft of the first drive motor 412. After the mounting frame 413 rotates half a revolution, the thruster 416 moves to the bow end of the submersible measurement platform 4. Then, the thruster 416 is activated to push the submersible measurement platform 4 towards the water inlet 101. By setting the first drive motor 412, the mounting frame 413, and the mounting rod 415, the position of the thruster 416 at both ends of the submersible measurement platform 4 can be adjusted, thereby reducing the direct human involvement during the return trip of the submersible measurement platform 4.

[0107] To enable the collection of water samples from the main body 1 of the water tank, a water sampling device is installed on the submersible measurement platform 4. The water sampling device includes a sampler 801 (shown in...). Figure 6The sampler 801 is a cylinder, longitudinally fixed on the submersible measurement platform 4. The submersible measurement platform 4 has a cylindrical notch for installing the sampler 801. Four sampling tubes 802 are fixedly installed inside the sampler 801, arranged equidistantly around its circumference. The upper ends of the sampling tubes 802 are open and located outside the upper end of the sampler 801, allowing water from the main body 1 to flow into the sampling tubes 802 through their upper ends. A sampling cover plate 803 is installed above the sampler 801, rotatably mounted on the submersible measurement platform 4. The lower surface of the sampling cover plate 803 contacts the upper end of the sampling tubes 802. In the initial state, the sampling cover... The upper surface of plate 803 contacts and connects with the upper end of sampling tube 802, closing the opening at the upper end of sampling tube 802. A notch corresponding to sampling tube 802 is provided on sampling cover plate 803. After the notch on sampling cover plate 803 coincides with the opening on sampling tube 802, the area of ​​the opening on sampling tube 802 that is blocked gradually decreases and no longer closes. At this time, the water in the main body of water tank 1 can enter the sampling tube 802 through the notch. The lower surface of sampling cover plate 803 is fixedly connected to the output shaft of second drive motor 804. Second drive motor 804 is located below sampler 801, and the output shaft of second drive motor 804 is coaxially arranged with sampler 801. Second drive motor 804 is fixedly mounted on submersible measurement platform 4.

[0108] As the submersible measurement platform 4 advances, the switch of the second drive motor 804 is turned on. The second drive motor 804 drives the sampling cover plate 803 to rotate, and the notch on the sampling cover plate 803 rotates synchronously until the notch on the sampling cover plate 803 coincides with the opening on a sampling tube 802. The area of ​​the opening on the sampling tube 802 that is blocked gradually decreases and no longer closes. At this time, the water in the water tank body 1 can enter the sampling tube 802 through the notch. As the submersible measurement platform 4 continues to advance and the second drive motor 804 continues to drive, the notch on the sampling cover plate 803 coincides with the opening on the remaining three sampling tubes 802, completing the sequential sampling of the remaining three sampling tubes 802. This achieves the sampling of water samples at different locations during the movement of the submersible measurement platform 4.

[0109] To obtain the data required for the experiment inside the main body of the water tank 1, a Doppler current profiler 407, a side-scan sonar 408, a laser scanner 409, a pressure sensor 419, and a camera 410 are fixedly installed on the submersible measurement platform 4; the Doppler current profiler 407, the side-scan sonar 408, the laser scanner 409, the pressure sensor 419, and the camera 410 all use existing model technical components.

[0110] The Doppler current profiler 407 is fixedly mounted on the mounting platform 406 on the upper surface of the submersible measurement platform 4. The mounting platform 406 is fixedly mounted on the upper surface of the submersible measurement platform 4. The Doppler current profiler 407 is used to simultaneously acquire the vertical and lateral velocity distributions of the flow field under the ice sheet. Its measurement blind zone is less than 3 cm, the profile resolution is not less than 1 cm, and the measurement frequency of the Doppler current profiler 407 is not less than 2 MHz to ensure measurement accuracy in the near-ice sheet and near-bed surface areas.

[0111] The side-scan sonar 408 is fixedly installed on one side of the upper surface of the submersible measurement platform 4. The side-scan sonar 408 is used to scan and quantify the roughness of the bottom surface of the ice sheet.

[0112] The laser scanner 409 is located on the side of the submersible measurement platform 4. The laser scanner 409 is used to accurately measure the effective water depth from the bottom of the ice sheet to the riverbed.

[0113] The array of miniature pressure sensors 419 is deployed at both ends of the submersible measurement platform 4. They are fixedly installed at both ends of the submersible measurement platform 4 to simultaneously measure the pressure at the two ends and indirectly calculate the water surface slope (energy slope) by combining the platform's movement distance.

[0114] The camera 410 is fixedly mounted on the lower surface of the submersible measurement platform 4. An incandescent lamp 411 is installed on one side of the camera 410. The incandescent lamp 411 is fixedly mounted on the lower surface of the submersible measurement platform 4. The incandescent lamp 411 is an auxiliary light source for the close-up camera. The camera 410 is used to acquire images of riverbed sediment particles in order to analyze the sediment particle size distribution and bed morphology.

[0115] The control and data integration unit, encapsulated within the submersible measurement platform 4, includes a waterproof processor, a storage module, and a wireless transmission module. It controls the collaborative operation of the various sensors, synchronously collects data, integrates the data, and transmits it in real-time to the shore-based data processing center. The waterproof processor, storage module, and wireless transmission module all utilize existing technological components.

[0116] To process data within the main body of the water tank 1, the shore-based data processing center receives data streams from each unit and has built-in dedicated analysis software for:

[0117] 1. Based on the pressure difference collected by the 419 array of miniature pressure sensors and the platform travel distance, the water surface slope (energy slope) J is calculated using fluid dynamics formulas;

[0118] 2. Integrate flow velocity data, effective water depth data, and real-time water temperature data to calculate the cross-sectional average flow velocity U and Reynolds number. R e and Froude's number F r Isohydraulic parameters;

[0119] 3. Filter and extract features from the data acquired by the side-scan sonar 408, and calculate the equivalent sand grain roughness height on the lower surface of the ice sheet. k s (Used to characterize ice sheet roughness); grayscale processing and particle identification are performed on the bed surface images to analyze the sediment particle size distribution characteristics, riverbed roughness coefficient, and bed surface morphology parameters;

[0120] 4. Based on the bed surface images obtained by the underwater camera system, the median particle size of the sediment is calculated using particle image analysis technology. d 50 Characteristic particle size d 10 , d 90 ;

[0121] 5. Based on the cross-sectional water velocity, suspended sediment concentration, and sediment characteristic parameters measured by the Doppler current profiler 407 and camera system, the suspended sediment transport rate is calculated based on these parameters. bedload transport rate and total sediment transport;

[0122] 6. Concentration of suspended solids in water samples obtained through laboratory analysis sampling devices. ;

[0123] 7. After completing all data acquisition and calculation, integrate all parameters such as ice sheet roughness, riverbed roughness, and water temperature obtained by the Doppler current profiler 407 to generate a comprehensive data report.

[0124] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for determining sediment transport parameters under indoor water tank ice cap flow conditions, characterized in that, include: Step 1: Pre-measurement preparation. Place the submersible measurement platform, which carries the Doppler current profiler, side-scan sonar, laser scanner, pressure sensor, underwater camera system, control and data integration unit and automatic water sampler, in the water tank and establish a communication connection with the shore-based data processing center. Place the simulated ice sheet above the water body, and then continuously inject test water into the water tank. Step 2: Device calibration and initial positioning. Zero-point calibration is performed on the pressure sensors on the submersible measurement platform. The standard scale calibration plate is photographed using an underwater camera system to complete the image scale calibration. The initial precise position of the platform is determined by combining GPS and an underwater acoustic positioning system. Step 3: Dynamic Synchronous Measurement The submersible measurement platform is controlled to move at a constant speed along the water tank track. During the movement, water samples are collected from the cross section using an automatic water sampler. Simultaneously, the measurement equipment on the submersible measurement platform is activated to obtain cross section test data. Step 4: Data Integration and Processing: All data streams collected in Step 3 are transmitted in real time to the control and data integration unit. The control and data integration unit then integrates the data and transmits it to the shore-based data processing center for further processing. Step 5: Result Output and Verification Integrate all processed parameters to generate a comprehensive sediment transport parameter dataset for the section where the submersible measurement platform is located; compare and verify the calculated suspended sediment concentration with the suspended sediment concentration obtained through water sample analysis to evaluate the measurement accuracy; In step three, vertical and lateral velocity profile data of the flow field are continuously acquired using a Doppler velocity profiler. The topography of the ice sheet underside was continuously scanned using side-scan sonar. The water depth in the tank was measured using a laser scanner; Pressure data at both ends of the submersible measurement platform are collected using pressure sensors, and the pressure values ​​at both ends are continuously recorded. Acquire images of the bed surface at fixed points or continuously using an underwater camera system; When the submersible measurement platform travels to different positions in the water tank, it triggers the automatic water sampler to collect water samples at key locations. The shore-based data processing center processes various data acquired from Doppler current profilers, side-scan sonar, laser scanners, pressure sensors, and underwater camera systems. 1) Calculate the water surface slope J based on the pressure difference collected by the pressure sensor and the platform's travel distance, combined with fluid dynamics formulas; 2) Integrate flow velocity data, effective water depth data, and real-time water temperature data to calculate the cross-sectional average flow velocity U and Reynolds number. R e and Froude's number F r ; 3) Filter and extract features from the data acquired by the side-scan sonar, and calculate the equivalent sand grain roughness height on the lower surface of the ice sheet. k s Grayscale processing and particle identification were performed on the bed surface images to analyze the characteristics of sediment particle size distribution, riverbed roughness coefficient, and bed surface morphology parameters. 4) Based on the bed surface images obtained by the underwater camera system, the median particle size of the sediment is calculated using particle image analysis technology. d 50 Characteristic particle size d 10 , d 90 ; 5) Based on the cross-sectional water velocity and sediment characteristics measured by the Doppler current profiler and camera system, the suspended sediment concentration and boundary shear stress in the cross-sectional water body are calculated. Parameters, based on the above parameters, calculate the suspended sediment transport rate. bedload transport rate and total sediment transport; 6) Concentration of suspended solids in water samples obtained through laboratory analysis sampling devices. ; 7) After all data acquisition and calculation are completed, a comprehensive data report is generated.

2. The method for determining sediment transport parameters under ice cap flow conditions in an indoor water tank according to claim 1, characterized in that: In step one, the Doppler current profiler has a measurement blind zone of ≤3cm and a profile resolution of ≥1cm; the underwater camera system is equipped with a camera and an auxiliary light source to acquire images of riverbed sediment particles in order to analyze the sediment particle size distribution and bed morphology.

3. A device for measuring sediment transport parameters under indoor flume ice cap flow conditions, used to implement the method for measuring sediment transport parameters under indoor flume ice cap flow conditions as described in any one of claims 1-2, characterized in that... include: The main body of the water tank (1) used to simulate the water flow environment is covered with test sand at the bottom. The two ends are respectively equipped with a water pump (2) with adjustable flow rate and a water outlet (7) for water discharge. One side of the main body of the water tank (1) is connected to the output end of the water pump (2) through the water inlet (101) set on it. The input end of the water pump (2) is connected to the water storage tank (102). The water storage tank (102) is connected to the other side of the main body of the water tank (1) through a water pipe, so that the main body of the water tank (1), the water pump (2), and the water storage tank (102) form a circulation. A water sampling device includes a sampling tube (802) for collecting water samples from the main body of the water tank (1) at different times; The submersible measurement platform (4) is provided with a first sliding plate (417), which is slidably connected to the first slide rail (6) on the inner wall of the water tank body (1). The submersible measurement platform (4) is equipped with a Doppler current profiler (407), a side-scan sonar (408), a laser scanner (409), a pressure sensor (419), a camera (410), and a sampler (801). The submersible measurement platform (4) can adjust the spatial position of the above components relative to the water tank body (1) to adapt to different measurement ranges. The submersible measurement platform (4) can adjust the sampling position of the sampler (801). The control and data integration unit is encapsulated inside the submersible measurement platform (4), including a waterproof processor, a storage module and a wireless transmission module, used to control the collaborative work between various sensors, synchronously collect data and transmit the data to the shore-based data processing center in real time; The shore-based data processing center receives data streams from the control and data integration unit and performs subsequent data processing.

4. The device for measuring sand transport parameters under indoor water tank ice cap flow conditions according to claim 3, characterized in that: The submersible measurement platform (4) also includes a first drive motor (412) fixedly mounted on its lower surface. The two ends of the first drive motor (412) are fixedly connected to the mounting bracket (413). The mounting bracket (413) is fixedly connected to the mounting rod (415) for mounting the thruster (416). The mounting rod (415) is provided with a thruster (416) for moving the submersible measurement platform (4). The water sampling device also includes sampling tubes (802) fixedly installed on the sampler (801). The sampler (801) is fixed on the submersible measurement platform (4). There are four sampling tubes (802) arranged on the sampler (801) in a circumferentially equidistant manner. A sampling cover plate (803) is provided on the upper surface of the sampler (801). The sampling cover plate (803) is rotatably installed on the submersible measurement platform (4). The sampling cover plate (803) is provided with a notch corresponding to the sampling tube (802). Through the notch, water can be ensured to enter the sampling tube (802). The lower surface of the sampling cover plate (803) is fixedly connected to the output shaft of the second drive motor (804).

5. The device for measuring sand transport parameters under indoor water tank ice cap flow conditions according to claim 4, characterized in that: A Doppler current profiler (407) is fixedly installed on the upper surface of the submersible measurement platform (4), a side-scan sonar (408) is fixedly installed on one side of the upper surface of the submersible measurement platform (4), a laser scanner (409) is located on the side of the submersible measurement platform (4), a pressure sensor (419) is fixedly installed at both ends of the submersible measurement platform (4), and a camera (410) is fixedly installed on the lower surface of the submersible measurement platform (4).

6. The device for measuring sand transport parameters under indoor water tank ice cap flow conditions according to claim 5, characterized in that: An incandescent lamp (411) is provided on one side of the camera (410), and the incandescent lamp (411) is fixedly installed on the lower surface of the submersible measurement platform (4).

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