Whole tide type tide forecasting table compiling and using method for sea area channel

Abstract

The invention discloses a sea area channel on-way full tide type tide forecast table compiling and using method, and the method comprises the steps: carrying out the simulation calculation of channel on-way hourly tide data of a sea area where a channel is located under different grading tidal ranges through a three-dimensional tide numerical model, and compiling a channel on-way tide forecast table; according to the method, linear interpolation can be conveniently carried out according to the forecast tidal range in the tide forecast table, the hourly navigation water flow conditions of the navigation channel along the way can be rapidly obtained, data such as the vertical average flow speed, the vertical average flow direction and the vertical average transverse flow in the designed ship type full-load draft range are included, and a basis is provided for formulating a ship control and piloting scheme. The method overcomes the defect that an existing tide forecast table only obtains average flow velocity and average flow direction data in all water depth ranges of a channel based on a two-dimensional digital model, and has the advantages of being more in line with the actual flow field, more suitable for the actual navigation, easy and convenient to use and the like.

Description

Technical Field

[0001] The present invention belongs to the field of water transport engineering industry construction, maintenance and operation, as well as the field of navigation and ocean forecasting, and relates to the preparation and use of a full-tide tidal current forecast table based on a three-dimensional tidal current numerical model along a sea channel. Background Art

[0002] The width of the channel required for safe navigation of ships is closely related to the velocity, direction and cross-flow along the channel. The velocity, direction and cross-flow along the channel are not only affected by the topography, such as the velocity and cross-flow may be significantly larger than the general sections near the breakwater gate or the regulation buildings and islands, but also closely related to the tide time (such as high tide, high tide, low tide, etc.) and tidal range, and the tidal range is closely related to the tidal type (high tide, medium tide, low tide).

[0003] The tide forecast tables currently released in the industry (such as the tide table compiled by the China National Marine Information Center) use two-dimensional tidal numerical models based on the impact of astronomy on tides to forecast tide levels for some long-term tide stations along the coast of the country in the coming years, as well as tidal forecasts for important sea area stations in the coming years. The tidal forecast content is divided into two situations: ① Reciprocating flow site The tide forecast table includes the daily turning time, maximum flow speed and the time when it occurs.

[0004] ② Rotating flow property site The tide forecast table includes the two maximum flow velocities and directions and the two minimum flow velocities and directions and the times of their occurrence during one tidal cycle (approximately one tidal cycle) (tide by tide).

[0005] The current forecast of the existing tide forecast table has the following deficiencies: ①Tidal current forecasting stations usually have only one forecasting point in a certain sea area, which is located at the public shipping route in the open sea, far away from the waters of the port approaching waterways, poorly representative, and does not cover the range along the waterway, which obviously cannot meet the needs of navigation; ② Although daily or tide-by-tide tidal data are given, only the flow velocity and direction of rapids and turning points are given. The total flow velocity, direction and cross-current data during the entire navigation period are not given, which obviously cannot meet the navigation needs.

[0006] ③ The flow velocity and direction data are for the entire water depth range of the channel, and there is a lack of flow velocity, flow direction and cross-flow data within the full-load draft depth range of the designed ship type.

[0007] ④ The flow velocity and direction data are based on the two-dimensional tidal current numerical model, not the three-dimensional tidal current numerical model, and cannot reflect the distribution of flow velocity and direction in the vertical direction.

[0008] In addition, the existing three-dimensional tidal numerical model has technically reached the level of "accurately simulating and calculating, and giving the hourly flow velocity, flow direction and cross-current data along the waterway in future years based on the tide data in the tide forecast table". However, if it is implemented in this way, the amount of calculation will be huge and a large number of tables will be generated, which is very inconvenient for guiding navigation. Summary of the invention

[0009] In order to solve the above problems, the present invention discloses a method for compiling and using a full-tide tidal current forecast table along a sea channel based on a three-dimensional tidal current numerical model.

[0010] Previous two-dimensional numerical modeling studies have shown that the maximum cross-current at the entrance of some ports, such as the Lianyungang Port Flag Tower, is positively correlated with the tidal range. The reason is that the sea area of ​​the port is not affected by runoff and is completely controlled by the tide, and the size of the cross-current at the entrance is completely determined by the tidal range.

[0011] Therefore, the present invention proposes to calculate the hourly tidal current along the waterway under the graded tidal range (such as tidal range of 5.5m, 5.0m, 4.5m, 4.0m, 3.5m, 3.0m, 2.5m, 2.0m, 1.5m, 1.0m, covering astronomical spring tide, astronomical medium tide and astronomical low tide, so it is called "full tide type") of the tidal station in the sea area where the waterway is located, and obtain the navigable water flow condition data, including flow velocity, flow direction and cross flow, and compile into a tidal current forecast table (hourly) along the waterway under different graded tidal ranges; when in use, according to the predicted tidal range of the tidal station given by the tidal forecast table, by querying the tidal current data given by the tidal current forecast table (hourly) along the waterway under the adjacent graded tidal range, linear interpolation can be performed, so as to quickly determine the hourly navigable water flow conditions along the waterway, and provide a basis for the early formulation of the ship's maneuvering and pilotage plan. In this way, the accuracy requirements can be met, and the amount of calculation and the generated tables can be greatly reduced, which is convenient for use.

[0012] Specifically, the technical solution of the present invention includes the following steps: S1. Establish a three-dimensional tidal numerical model of the waterway and its sea area; S2. Use the measured tide level, current velocity and flow direction data of the sea area where the channel is located to verify the three-dimensional tidal numerical model and determine the calculation parameters; S3. Use the verified three-dimensional tidal numerical model to simulate and calculate the hourly (based on the time when the tidal station is at high and low tide, such as 3 hours before high and low tide to 3 hours after high and low tide, the time interval is 1 hour or 30 minutes, 15 minutes, the same below) tidal level, vertical flow velocity and flow direction of each layer along the waterway at different tidal ranges (generally, the tidal range is 0.5m, such as tidal range of 5.5m, 5.0m, 4.5m, 4.0m, 3.5m, 3.0m, 2.5m, 2.0m, 1.5m, 1.0m, and the maximum and minimum tidal ranges should cover the astronomical spring tide, astronomical medium tide and astronomical low tide of previous years, so it is called "full tide type") tidal range along the waterway at different levels (the time when the tidal station is at high and low tide is used as the benchmark, such as 3 hours before high and low tide to 3 hours after high and low tide, the time interval is 1 hour or 30 minutes, 15 minutes, the same below); S4. Based on the numerical simulation calculation results of S3, calculate the hourly tide level of each characteristic point along the channel under different tidal ranges, the vertical average flow velocity within the full-load draft range of the designed ship type, the vertical average flow direction and the vertical average cross flow; S5. Based on the calculation results of S4, prepare a tidal current forecast table along the waterway, including the hourly tidal level at each characteristic point along the waterway, the vertical average flow velocity within the full load draft range of the designed ship type, the vertical average flow direction and the vertical average cross flow.

[0013] In some embodiments, the S1 may include: S1a. Determine the calculation range and open boundary setting of the three-dimensional tidal numerical model according to the topographic characteristics of the sea area where the channel is located, as well as the tidal wave propagation characteristics and tidal current movement characteristics; S1b. According to the design scale and plane layout of the waterway and the terrain characteristics along the waterway, the plane grid division of the three-dimensional tidal numerical model is carried out. The grid density should be able to generalize the boundaries between the land coastline and the underwater terrain, the waterway and its surrounding buildings. The grids in the key research waters need to be encrypted; S1c. According to the full-load draft of the channel design ship type and the tidal range in the area, determine the number of vertical calculation layers of the three-dimensional tidal numerical model. The number of layers should be able to accurately reflect the changes in flow velocity and direction within the full-load draft range of the channel design ship type during the tidal cycle.

[0014] In some embodiments, S3 may include: S3a. According to the measured tidal range at the tidal station in the sea area where the waterway is located, determine the graded tidal range that needs to be compiled for the tidal forecast table and the flow field calculation for the three-dimensional tidal numerical model; S3b. Adjust the open boundary input conditions of the three-dimensional tidal numerical model so that the calculated values ​​of the tidal ranges of each level at the tidal station in the sea area where the channel is located calculated by the numerical model are the same as the tidal ranges of each level for which the tidal forecast table needs to be compiled; S3c. Using the three-dimensional tidal numerical model, based on the open boundary input conditions corresponding to each graded tidal range, the hourly tidal level, vertical flow velocity and flow direction of each layer along the waterway under each graded tidal range are simulated.

[0015] In some embodiments, the S4 may include: S4a. According to the plan layout of the waterway, the layout of buildings or structures along the waterway, and the flow field characteristics along the waterway, determine the locations of the characteristic points along the waterway that need to be included in the tidal current forecast table; S4b. For each characteristic point along the channel included in the tidal forecast table, the hourly tidal level, vertical stratified flow velocity and flow direction of each characteristic point along the channel calculated based on the three-dimensional tidal numerical model are calculated to calculate its full-load draft depth range of the designed ship type. H m The hourly vertical average velocity V m , Flow direction , which is calculated as follows:

[0016] In formula (1), i The three-dimensional tidal current numerical model i Layer number, i =1 for the surface layer, i=n For the bottom layer, n is the total number of vertical layers of the three-dimensional tidal flow numerical model; V i and The flow velocity and direction of a certain layer at a certain feature point; k The number of calculation layers of the three-dimensional tidal numerical model within the full-load draft depth range of the ship type is designed for this characteristic point. The calculation result of is rounded. k ≤ n ; H is the still water depth of the feature point that does not change with the tide level; ζ is the hourly tide level of the feature point.

[0017]

[0018] In formula (2), arctan2(x) is the four-quadrant inverse tangent function; if the calculated If it is less than 0°, add 360°.

[0019] S4c calculates the hourly vertical average crossflow within the full load draft range of the designed ship type at each characteristic point along the channel based on the calculation results of S4b V c , which is calculated as follows: In formula (3), is the channel strike angle of the feature point.

[0020] In some embodiments, the S5 may include: S5a. A separate table of tidal current forecast along the waterway is prepared for each tidal range classification, including the hourly tidal level at each characteristic point along the waterway, the vertical average flow velocity within the full-load draft range of the designed ship type, the vertical average flow direction and the vertical average cross flow; S5b. Gather the tidal current forecast sub-tables along the waterway under different tidal range classifications to form a complete tidal current forecast table along the waterway.

[0021] The method of using the above-mentioned tidal current forecast table for all tide types along the sea channel is to perform linear interpolation based on the predicted tidal range of the tide station given by the tidal forecast table, by querying the tidal data given by the hourly tidal current forecast table along the channel under adjacent graded tidal ranges, so as to quickly determine the hourly navigation flow conditions along the channel, thereby providing a basis for the ship's maneuvering and early formulation of pilotage plans.

[0022] In some embodiments, the following steps may be included: (1) Based on the predicted tidal range of a tidal process given in the tidal forecast table, query the tidal data given in the tidal forecast table along the waterway under the adjacent graded tidal range; (2) Linear interpolation is performed based on the tidal range to obtain the hourly navigation flow conditions at each characteristic point along the waterway, including the tidal level, the vertical average flow velocity within the range of the designed ship's full-load draft, the vertical average flow direction and the vertical average cross flow.

[0023] In one embodiment, according to the predicted tidal range (e.g., 4.9 m) of a certain tidal process (e.g., the daily tide on September 18th of the lunar calendar) given in the tidal forecast table, the tidal data given in the tidal forecast table along the waterway under adjacent graded tidal ranges (tidal range of 5 m and tidal range of 4.5 m) are queried, and linear interpolation is performed based on the tidal range to obtain the hourly navigable flow conditions at each characteristic point along the waterway, including tidal level, vertical average flow velocity within the full load draft range of the designed ship type, vertical average flow direction, and vertical average cross flow.

[0024] Applications: It should be noted that the present invention is applicable to the preparation and use of tidal current forecast tables for all tidal navigation periods along the sea channel, especially the preparation and use of tidal current forecast tables along the sea channel under normal weather conditions where tidal effects dominate. In strong wind conditions or in estuary waters, the actual flow velocity, flow direction and cross flow will be affected by strong winds or runoff factors, and there will be some deviations, so it is necessary to pay attention when using it.

[0025] The present invention provides a method for compiling a tidal current forecast table for a sea channel based on a three-dimensional tidal current numerical model, which has the following beneficial effects: ① The hourly vertical average velocity, vertical average flow direction and vertical average cross-current data of each characteristic point along the sea channel and the full-load draft depth of the designed ship type under different tidal conditions can be given. In this way, when designing the overall waterway project, the determination of the waterway operation standard and the number of times the waterway is navigable can further consider the influence of the combination of cross-current and tidal level, and determine the waterway operation standard and navigation guarantee rate more comprehensively and reasonably, overcoming the shortcomings of the current waterway operation standard that the cross-current limit value adopts the maximum cross-current calculated by actual measurement or numerical model, the number of days the waterway is navigable is calculated according to the number of days with wind, waves, fog and thunder, and the default waterway cross-current does not exceed the design operation standard.

[0026] ② It can provide the hourly vertical average flow velocity, vertical average flow direction and vertical average cross flow data within the full-load draft depth of the designed ship type under different tidal range conditions at each characteristic point along the sea channel. In this way, according to the tidal range given in the tidal forecast table of the sea area, through linear interpolation, the hourly navigation flow conditions along the channel can be quickly determined, including the tidal level, the vertical average flow velocity, vertical average flow direction and vertical average cross flow within the full-load draft depth of the designed ship type, so as to provide a basis for the early formulation of ship maneuvering and pilotage plans. This can not only meet the accuracy requirements, but also greatly reduce the amount of calculation and the generated tables, making it easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 :A flow chart of the preparation and use of a full-tide tidal current forecast table along a sea channel.

[0028] Figure 2 : Schematic diagram of the waterway plan layout of an embodiment of the present invention.

[0029] Figure 3 : Calculation range and grid division diagram of the three-dimensional tidal current numerical model according to an embodiment of the present invention.

[0030] Figure 4 : Calculation result diagram of the rapid surface flow field according to an embodiment of the present invention.

[0031] Figure 5 : Schematic diagram of the locations of characteristic points within a waterway according to an embodiment of the present invention.

[0032] Figure 6 : Schematic diagram of vertical flow velocity distribution of characteristic point C5 2 hours before high tide under 5.0m graded tidal range according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention is described in detail below with reference to the embodiments and drawings.

[0034] A port on the coast of my country has a 300,000-ton channel and a long-term tide station. The layout of the port area and channel is shown in Figure 2The design ship type of the 300,000-ton channel is a 300,000-ton bulk carrier, whose full-load draft is 23.0m and the design bottom elevation of the channel is -22.6m (the local theoretical lowest tide level); when a 300,000-ton bulk carrier enters the port fully loaded, it needs to sail in the WY section of the channel during the tide, and the tide period is 2 hours before high tide to 2 hours after high tide.

[0035] Preparation and use of the full tide forecast table for the WY section of the waterway, such as Figure 1 As shown, the following steps are included: Step 1: Establish a three-dimensional tidal numerical model of the waterway and the sea area where it is located.

[0036] Firstly, the calculation range and opening boundary position of the three-dimensional tidal numerical model were determined according to the tidal and current characteristics and terrain characteristics of the sea area where the channel is located. Figure 3 .

[0037] Then, the computational domain is meshed using unstructured grids. To ensure the accuracy of flow field simulation in the waters of the WY section of the waterway, the local grids are encrypted, and the plane scale of the minimum grid is about 20 m.

[0038] Finally, considering the large tidal range on the nearshore side of the sea area where the channel is located (generally the tidal range can reach more than 5.0m), the flow velocity and direction at different water depths of the channel will change significantly with the tide level. In order to more accurately reflect the changing total water depth of the channel during the tidal cycle with different tidal ranges, the flow velocity, flow direction, and cross-flow changes within the full-load draft depth range of the ship type (from the water surface to 23.0m underwater) are designed to ensure that the water layer thickness of each calculation layer does not exceed 1m, and the number of vertical stratification layers of the three-dimensional tidal numerical model is determined to be 30.

[0039] Step 2: Use the measured tide level, flow velocity, and flow direction data of the sea area where the waterway is located to verify the three-dimensional tidal numerical model and determine the calculation parameters.

[0040] The large-scale fixed-point hydrological test data in the sea area where the channel is located in April and September 2023, as well as the ADCP flow field monitoring data of the mouth section from September to October 2023, are used for comparison and verification with the model calculation results, and the calculation parameters are adjusted to make the verification results of the tide level, flow velocity and flow direction of the measuring points meet the accuracy requirements specified in the "Technical Specifications for Simulation Tests of Water Transport Engineering" (JTS / T 231-2021). After verification and debugging of the measured data, the Manning roughness coefficient of the bed in the model is determined to be 0.015~0.025, and the vertical eddy viscosity coefficient of the water flow is determined to be 1.2.

[0041] Step 3: Use the verified three-dimensional tidal numerical model to simulate and calculate the hourly tide level, stratified flow velocity and flow direction under different tidal ranges in the sea area where the waterway is located.

[0042] First, according to the analysis results of the measured tidal range of the long-term tide station from 2013 to 2022, the tidal range on the nearshore side of this sea area is generally between 2.0m and 5.5m. Therefore, 2.0m, 2.5m, 3.0m, 3.5m, 4.0m, 4.5m, 5.0m, and 5.5m are determined as the graded tidal ranges for the three-dimensional flow field calculation.

[0043] Then, the open boundary input conditions of the three-dimensional tidal numerical model (the water level at the open boundary of the model in this embodiment) are adjusted so that the calculated tidal range values ​​of each level of the tidal station calculated by the three-dimensional tidal numerical model are the same as the aforementioned graded tidal ranges.

[0044] Finally, using the three-dimensional tidal numerical model verified in step 2, based on the open boundary input conditions corresponding to each graded tidal range, the hourly three-dimensional flow field under each tidal range in the sea area where the channel is located is calculated, including the hourly tidal level, the flow velocity and flow direction of each vertical layer. Among them, under the condition of a tidal range of 5.0m at the tidal station, the rapid surface flow field in the waters of the WY section of the channel is shown in Figure 4 .

[0045] Step 4: Based on the calculation results of hourly tide level, stratified flow velocity and flow direction under different graded tidal ranges of the three-dimensional tidal numerical model, the hourly vertical average flow velocity, vertical average flow direction and vertical average cross flow within the full load draft range of the design ship type at each characteristic point along the channel are calculated.

[0046] According to the calculation results of the flow field, in the mouth section of the channel, due to the effect of the breakwater, the flow velocity is relatively high and the flow state is complex. The tidal flow direction and the direction of the WY section of the channel have a large intersection angle, which is more likely to cause a large cross current than other sections, and needs to be paid special attention to. Therefore, when determining the characteristic points included in the compilation of the tidal forecast table, a characteristic point is arranged every 1 km near the port entrance of the WY section (2 km from the mouth to the outside of the mouth), and a characteristic point is arranged every 2 km in the remaining sections, numbered from west to east as C1~C10, see Figure 5 .

[0047] For the characteristic points of the waterway included in the compilation of the tidal forecast table, the hourly tidal level, layered flow velocity and flow direction of the characteristic point under different tidal ranges calculated by the three-dimensional tidal numerical model are used. Formulas (1) and (2) are used to calculate the hourly vertical average flow velocity and vertical average flow direction of the characteristic point under different tidal ranges and within the full-load draft range of the designed ship type. Among them, the vertical flow field of the C5 characteristic point 2 hours before the high tide is shown when the tidal range of the tidal station is 5.0m. Figure 6 At this time, the calculation layer number of the three-dimensional tidal numerical model within the full-load draft range of the designed ship type is 28 layers, and it is necessary to calculate the vertical average flow velocity and flow direction of the 1st to 28th layers, that is, k Take it as 28.

[0048] Based on the calculation results of the hourly vertical average flow velocity and vertical average flow direction within the full-load draft range of the designed ship type under different tidal ranges at the characteristic points C1 to C10, combined with the channel strike angle of the WY section of the channel (63° to 243°), formula (3) is used to calculate the hourly vertical average cross flow within the full-load draft range of the designed ship type under different tidal ranges at each characteristic point.

[0049] Step 5: Based on the calculation results of step 4, prepare a tidal current forecast table along the waterway.

[0050] Based on the above-mentioned tidal ranges of 2.0m, 2.5m, 3.0m, 3.5m, 4.0m, 4.5m, 5.0m and 5.5m at the long-term tidal station, the compilation of the sub-tables of the tidal forecast table is carried out, that is, a sub-table is a tidal forecast table along the WY section of the waterway under a certain graded tidal range at the long-term tidal station.

[0051] The navigation period of the WY section of the channel is 2 hours before high tide and 2 hours after high tide. The navigation period is divided into 5 moments at intervals of 1.0 hour, namely 2 hours before high tide, 1 hour before high tide, high tide, 1 hour after high tide, and 2 hours after high tide. In each sub-table (i.e. based on the tidal station reaching the aforementioned graded tidal range as the benchmark), fill in the vertical average flow velocity, vertical average flow direction and vertical average cross flow of each characteristic point along the channel corresponding to these 5 moments within the range of the designed ship's full-load draft. The sample table under the condition of a graded tidal range of 5.0m is shown in Table 1.

[0052] Table 1 Example 5.0m graded tidal range tidal forecast table

[0053] Note: The above table gives the forecast data of some characteristic points Finally, the various sub-tables under the graded tidal range of 2.0m, 2.5m, 3.0m, 3.5m, 4.0m, 4.5m, 5.0m and 5.5m are combined to form the full tidal current forecast table for the WY section of the waterway.

[0054] Step 6: Based on the predicted tidal range of a tidal process given in the tidal forecast table, query the tidal data given in the tidal forecast table along the waterway under adjacent graded tidal ranges, and perform linear interpolation to obtain the hourly navigable water flow conditions at each characteristic point along the waterway.

[0055] A 300,000-ton bulk carrier needs to enter the port during the day on September 18th of the lunar calendar. The tide forecast table is queried, and the daily tidal range at the long-term tide station is 4.9m. The tidal data of the tidal forecast table along the channel under the tidal range of 5m and 4.5m are queried. After linear interpolation based on the tidal range, the hourly tidal level of each characteristic point along the channel, the vertical average flow velocity within the full-load draft range of the ship, the vertical average flow direction and the vertical average cross flow can be obtained.

[0056] The above-mentioned related explanations and descriptions of the embodiments are for the convenience of those skilled in the art to understand and apply the present invention. It is obvious that those familiar with the art can easily make various modifications to these contents and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above-mentioned related explanations and descriptions of the embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A method for compiling a full-tide tidal current forecast table along a sea channel, characterized in that: The hourly tidal current field along the waterway under the graded tidal range of the tidal station in the sea area where the waterway is located is calculated to obtain the navigable water flow condition data, including flow velocity, flow direction, and cross current, and compile an hourly tidal current forecast table along the waterway under different graded tidal ranges; the full tide type refers to the coverage of astronomical spring tide, astronomical moderate tide, and astronomical low tide.

2. The method for compiling a full-tide tidal current forecast table along a sea channel according to claim 1 is characterized in that: The following steps are involved: S1. Establish a three-dimensional tidal numerical model of the waterway and its sea area; S2. Use the measured tide level, current velocity and flow direction data of the sea area where the channel is located to verify the three-dimensional tidal numerical model and determine the calculation parameters; S3. Using the verified three-dimensional tidal numerical model, simulate and calculate the hourly tidal level, vertical flow velocity and flow direction of each layer along the waterway under different tidal ranges at the tidal station in the sea area where the waterway is located; S4. Based on the simulation calculation results of S3, calculate the hourly tide level of each characteristic point along the channel under different tidal ranges, the vertical average flow velocity, the vertical average flow direction and the vertical average cross flow within the full load draft range of the designed ship type; S5. Based on the calculation results of S4, prepare a tidal current forecast table along the waterway, including the hourly tidal level at each characteristic point along the waterway, the vertical average flow velocity within the full load draft range of the designed ship type, the vertical average flow direction and the vertical average cross flow.

3. The method for compiling a full-tide tidal current forecast table along a sea channel according to claim 2 is characterized in that: The S1 includes: S1a. Determine the calculation range and open boundary setting of the three-dimensional tidal numerical model according to the topographic characteristics of the sea area where the channel is located, as well as the tidal wave propagation characteristics and tidal current movement characteristics; S1b. Perform plane grid division of the three-dimensional tidal numerical model according to the design scale and plane layout of the waterway and the terrain characteristics along the waterway; S1c. Determine the number of vertical calculation layers of the three-dimensional tidal numerical model based on the full-load draft of the designed ship type in the channel and the tidal range in the area.

4. The method for compiling a full-tide tidal current forecast table along a sea channel according to claim 2 is characterized in that: The S3 includes: S3a. According to the measured tidal range at the tidal station in the sea area where the waterway is located, determine the graded tidal range that needs to be compiled for the tidal forecast table and the flow field calculation for the three-dimensional tidal numerical model; S3b. Adjust the open boundary input conditions of the three-dimensional tidal numerical model so that the calculated values ​​of the tidal ranges of various levels at the tidal stations in the sea area where the channel is located calculated by the numerical model are the same as the tidal ranges of various levels for which the tidal forecast table needs to be compiled; S3c. Using the three-dimensional tidal numerical model, based on the open boundary input conditions corresponding to each graded tidal range, the hourly tidal level, vertical flow velocity and flow direction of each layer along the waterway under each graded tidal range are simulated.

5. The method for compiling a full-tide tidal current forecast table along a sea channel according to claim 2 is characterized in that: The S4 includes: S4a. According to the plan layout of the waterway, the layout of buildings or structures along the waterway, and the flow field characteristics along the waterway, determine the locations of the characteristic points along the waterway that need to be included in the tidal current forecast table; S4b. For each characteristic point along the channel included in the tidal forecast table, the hourly tidal level, layered flow velocity and flow direction of the characteristic point under different tidal ranges calculated based on the three-dimensional tidal numerical model are calculated to calculate the depth of the designed ship within the full load draft range. H m The hourly vertical average velocity V m , Flow direction , which is calculated as follows: In formula (1), i The three-dimensional tidal current numerical model i Layer number, i =1 for the surface layer, i=n For the bottom layer, n is the total number of vertical layers of the three-dimensional tidal flow numerical model; V i and The flow velocity and direction of a certain layer at a certain feature point; k The number of calculation layers of the three-dimensional tidal current numerical model within the full-load draft depth range of the ship type is designed for this characteristic point, and its value is The calculation result of is rounded. k ≤ n ; H is the still water depth of the feature point that does not change with the tide level; ζ The hourly tide level for the feature point; In formula (2), arctan2(x) is the four-quadrant inverse tangent function; if the calculated If it is less than 0°, add 360°; S4c. Based on the calculation results of S4b and the direction angle of the channel, calculate the hourly vertical average cross current Vc as follows: In formula (3), is the channel strike angle of the feature point.

6. The method for compiling a full-tide tidal current forecast table along a sea channel according to claim 2 is characterized in that: The S5 includes: S5a. A separate table of tidal current forecast along the waterway is prepared for each tidal range classification, including the hourly tidal level at each characteristic point along the waterway, the vertical average flow velocity within the full-load draft range of the designed ship type, the vertical average flow direction and the vertical average cross flow; S5b. Gather the tidal current forecast sub-tables along the waterway under different tidal range classifications to form a complete tidal current forecast table along the waterway.

7. The method for using the full tide type tidal current forecast table along the sea channel according to any one of claims 1 to 6, characterized in that: When in use, based on the predicted tidal range of the tide station given by the tidal forecast table, linear interpolation is performed by querying the tidal data given by the hourly tidal forecast table along the waterway under adjacent graded tidal ranges to quickly determine the hourly navigable water flow conditions along the waterway, providing a basis for ship maneuvering and early formulation of pilotage plans.

8. The method for using the full tide type tidal current forecast table along the sea channel according to claim 7 is characterized in that: The following steps are involved: (1) Based on the predicted tidal range of a tidal process given in the tidal forecast table, query the tidal data given in the tidal forecast table along the channel under the adjacent graded tidal range; (2) Linear interpolation is performed based on the tidal range to obtain the hourly navigation flow conditions at each characteristic point along the waterway, including the tidal level, the vertical average flow velocity within the range of the designed ship's full-load draft, the vertical average flow direction and the vertical average cross flow.

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