A ship wave simulation method based on XBeach ship path loop setting

Abstract

The present invention discloses a ship wave simulation method based on XBeach ship path cycle setting, comprising the following steps: using Delft3D in combination with engineering drawing interpolation to construct a water depth terrain grid in the experimental simulation area; setting ship parameters in the XBeach file; setting cyclic navigation path data parameters in the XBeach file; setting model running time, time step, sediment data and other model parameters in the XBeach file; using the XBeach model to perform long-term ship wave simulation calculations, outputting waterway scouring and silting simulation data, and obtaining ship wave scouring and silting simulation results. The present invention simulates the scouring of waterway revetments under the action of ship waves by setting the ship cycle path data in XBeach, thereby realizing the scouring simulation of revetments under the long-term action of ship waves, which is helpful to make quantitative calculation and analysis on the degree to which inland waterway revetments are affected by ship waves, and provides a theoretical basis for the design and maintenance of revetments.

Description

Technical Field

[0001] The invention belongs to the technical field of waterway engineering, and in particular relates to a ship wave simulation method based on XBeach ship path cycle setting. Background Art

[0002] Inland waterway revetments are important structures that protect the bank slopes on both sides of the waterway from erosion, prevent soil erosion, and stabilize the coastline. With the advancement of the construction of the Grand Canal Cultural Belt, the concept of green ecological waterway construction has led to the birth of various ecological revetments. At the same time, the large-scale ships in inland waterways have led to an increase in the scouring effect of ship waves on both sides of the waterway. Unlike traditional revetments such as mortar masonry, new ecological revetments are more susceptible to scouring by ship waves due to their permeability and eco-friendliness. Inland waterways are busy with ship navigation, and the ecological revetments on both sides will be affected by the long-term effects of ship waves, resulting in fill loss, and their stability may be affected.

[0003] Among the more advanced ship wave simulation technologies, XBeach, as a computational model for beach evolution simulation, has been widely used after many improvements by many scholars. The XBeach model has a simple interface and clear parameter settings. Its non-hydrostatic model can well simulate the impact of ship waves generated by ship navigation on the model waters, and the sediment transport can well simulate the movement of sediment in the channel, thereby obtaining the scouring and silting conditions of the channel.

[0004] Although Xbeach is widely used and reliable, most of the current research on ship waves focuses on the movement of sediment in the water when a ship sails through the simulated waters on a single trip, but there are few simulations of the scouring of both banks under the long-term action of ship waves. In addition, the non-hydrostatic model for simulating ship navigation in Xbeach cannot be deleted in the model settings, and it is impossible to add more ship models in a single calculation to simulate long-term ship navigation conditions. Summary of the invention

[0005] In order to solve the technical problems mentioned in the above background technology, the present invention proposes a ship wave simulation method based on XBeach ship path cycle setting.

[0006] In order to achieve the above technical objectives, the technical solution of the present invention is:

[0007] A ship wave simulation method based on XBeach ship path loop setting includes the following steps:

[0008] S1. Use Delft3D combined with engineering drawing interpolation to construct the water depth terrain grid of the experimental simulation area;

[0009] S2. Set the ship parameters in the ship.txt and ship.dep files of XBeach;

[0010] S3. Set the loop navigation path data parameters in the track file of Xbeach;

[0011] S4. Setting the parameters of the XBeach model in the param file of XBeach includes: running time, time step, sediment data and slope coefficient threshold;

[0012] S5. Use the XBeach model to perform ship wave simulation calculations for about ten days, output channel scouring and silting simulation data, and obtain ship wave scouring and silting simulation results.

[0013] Preferably, the specific operation of step S1 is: importing the waterway terrain sample file into Rgfgrid in Grid andbathymetry, drawing the terrain boundary according to the scattered distribution of water depth, using the spline function to draw grid lines along the boundary and center line, generating a grid file according to actual needs, wherein the grid of the grid file is a grid with a length of 100 meters and a width of 5 meters, and using the Quickin module and the generated grid file, the water depth is interpolated by using triangular interpolation and grid averaging methods.

[0014] Preferably, setting the ship.txt file in step S2 is specifically as follows: first, the size of the unit length dx and the unit width dy of the ship in ship.txt is set, in meters; then, the coefficient nx corresponding to the unit length of the ship and the coefficient ny corresponding to the unit width are set according to the actual size of the ship, dx×nx and dy×ny are the approximate length and width of the simulated ship size; finally, the ship simulation navigation mode is set, including flying, compute_force and compute_motion, and the names of the ship draft file shipgeom and the path file shiptrack are set.

[0015] Preferably, setting the ship.dep file in step S2 is specifically as follows: firstly, constructing a grid for simulating the ship according to dx and dy in ship.txt, and then setting the draft of the ship in each grid, wherein the draft of the bow is less than the draft of the stern, and the whole operation is set using Notepad as a method for opening the ship.dep file.

[0016] Preferably, the step S3 sets the closed loop navigation path data parameters in the track file of Xbeach, and the specific contents include:

[0017] (1) Calculate the number of ships sailing in the waterway at the same time based on the actual ship flow in the waterway;

[0018] (2) Based on the number of ships calculated in (1), in the water depth terrain grid of the experimental simulation area constructed by S1, positions on both sides of the channel are equally spaced as the starting points of each ship, and all the selected starting points form a closed loop trajectory for the ship's navigation; at the same time, at each turn of this closed loop trajectory, an additional 5 trajectory points are determined, and the time when the ship sails to each trajectory point is calculated in combination with the actual navigation speed of the ship. The coordinates of all trajectory points of each ship and the corresponding time are input into their respective Xbeach model track files.

[0019] Preferably, the step S4 sets the model running time, time step, sediment data and slope coefficient threshold in the param file of XBeach, including:

[0020] (1) In the Physical processes module, set the equations used in the model calculation and start the sediment movement simulation;

[0021] (2) Set the calculation time step in the Numerics input module;

[0022] (3) Set various boundary conditions in the Flow boundary condition parameters and Wave boundary condition parameters modules;

[0023] (4) Set the total simulation time of the model and the time interval model parameters for data output;

[0024] (5) Set sediment parameters and sediment calculation equation scour simulation parameters;

[0025] (6) In the Output variables module, set the parameter names to be output and the coordinates of the observation and verification points.

[0026] The beneficial effects brought by adopting the above technical solution are:

[0027] The present invention discloses a ship wave simulation method based on XBeach ship path cycle setting. By setting the ship's cycle path in the track file in the XBeach model, the influence of the long-term effect of ship waves on inland waterways can be simulated using fewer ship models. The present invention is helpful for analyzing the evolution of inland waterways under the long-term effect of ship waves, and is helpful for providing theoretical support for the design and stability verification of revetments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a flow chart of the steps of a ship wave simulation method based on XBeach ship path loop setting.

[0029] Figure 2 It is a schematic diagram of the water depth terrain grid of the Delft3D study area in an example of a ship wave simulation method based on the XBeach ship path loop setting of the present invention.

[0030] Figure 3 It is a schematic diagram of a ship model parameter setting interface in an example of a ship wave simulation method based on XBeach ship path cycle setting of the present invention.

[0031] Figure 4 It is a schematic diagram of the draft setting interface of the ship model in an example of a ship wave simulation method based on XBeach ship path cycle setting of the present invention.

[0032] Figure 5 This is a schematic diagram of a ship.txt file of all ship models in an example of a ship wave simulation method based on XBeach ship path loop setting of the present invention.

[0033] Figure 6 It is a schematic diagram of track files of all ship models in an example of a ship wave simulation method based on XBeach ship path loop setting of the present invention.

[0034] Figure 7 The present invention is a schematic diagram of the specific time and coordinate point settings of the ship model track file in an example of a ship wave simulation method based on XBeach ship path loop setting.

[0035] Figure 8 This is a schematic diagram of the evolution of the revetment under the long-term action of ship waves obtained through XBeach calculation results in an example of a ship wave simulation method based on the XBeach ship path cycle setting. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0037] like Figure 1 As shown, the present invention proposes a ship wave simulation method based on XBeach ship path cycle setting, comprising the following steps:

[0038] S1, using Delft3D combined with engineering CAD drawings to interpolate and construct the water depth terrain grid of the experimental simulation area; the specific operation is to import the terrain sample file into Rgfgrid in Grid and bathymetry, draw the terrain boundary according to the scattered distribution of water depth, use the spline function to draw grid lines along the boundary and center line, generate a grid of appropriate density according to actual needs, and perform local encryption according to actual conditions. When interpolating the terrain, it is necessary to select the existing water depth point sample file of the engineering river section, and perform local encryption on the sparse distribution of water depth points, so that the terrain can better simulate the actual water depth situation. Use the Quickin module and the generated grid file, and use triangular interpolation and grid averaging methods to interpolate the water depth. In addition, some grids without effective depth are processed by internal diffusion method, and for areas with large depth gradients, smoothing is used to make the river bottom smooth.

[0039] S2, set the ship parameters in the ship.txt and ship.dep files of XBeach; first set the size of dx and dy in ship.txt (unit: meter); then set nx and ny according to the actual size of the ship, ensuring that dx×nx and dy×ny are the approximate length and width of the simulated ship size; finally set the ship's simulated navigation mode (flying, compute_force, compute_motion) and the names of the ship's draft file (shipgeom) and path file (shiptrack). When setting the ship.dep file, first build a grid of simulated ships based on dx and dy in ship.txt, then set the draft of the ship in each grid, where the bow draft can be set smaller to reflect the specific situation of the ship. The entire operation can be set using Notepad as a method to open the ship.dep file.

[0040] S3, set the loop navigation path data parameters in the Xbeach track file; the specific contents include:

[0041] (1) Calculate the number of ships sailing in the waterway at the same time based on the actual ship flow in the waterway;

[0042] (2) According to the number of ships to be set in the model, several suitable locations are selected in the terrain and water depth grid constructed by S1 as the starting point of each ship, and all the selected starting points are used to form a circular trajectory of the ship's navigation; at the same time, more track points are determined in the route, and the time when the ship sails to the point is given in combination with the actual navigation speed of the ship. The coordinates of all track points of each ship and the corresponding time are input into their respective Xbeach model track files.

[0043] S4, set the model running time, time step, sediment data and other model parameters in the param file of XBeach; including:

[0044] (1) In the Physical processes module, set the equations used in the model calculation and start the sediment movement simulation;

[0045] (2) Set the calculation time step in the Numerics input module;

[0046] (3) Set various boundary conditions in the Flow boundary condition parameters and Wave boundary condition parameters modules;

[0047] (4) Set model parameters such as the total simulation time and the time interval for data output;

[0048] (5) Set scour simulation parameters such as sediment parameters and sediment calculation equations;

[0049] (6) In the Output variables module, set the parameter names to be output and the coordinates of the observation and verification points.

[0050] S5, use the XBeach model to perform long-term ship wave simulation calculations, output channel scouring and silting simulation data, and obtain ship wave scouring and silting simulation results; through the cyclic setting of the ship navigation model path, a better evolution result of the inland waterway revetment under the long-term action of ship waves can be obtained.

[0051] The embodiment selects the section from Shiqiao Ship Lock of Beijing-Hangzhou Grand Canal to Yangtze River Estuary for research, and uses relevant data from the ecological gabion project at the entrance of Xuyang Section of Beijing-Hangzhou Grand Canal into the Yangtze River to simulate the evolution of scouring and silting of inland waterway revetments under the long-term action of ship waves.

[0052] like Figure 2 As shown in the figure, by combining the CAD drawings provided by the project, Delft3D was used to construct the waterway research area's bathymetric topographic grid, where the bottom of the grid is the connection between the Yangtze River estuary and the inland waterway. Through the interpolation setting of the grid bathymetric topography, the elevation of the revetment, platform width and other contours on both sides of the channel can be reflected, which can be used as the grid area for the XBeach model to run.

[0053] After determining the model simulation area grid, the ship model needs to be set up. Figure 3As shown, set nx and ny in ship.txt according to the actual size of the ship, and ensure that dx×nx and dy×ny are the approximate length and width of the simulated ship size; finally, set the ship simulation navigation mode (flying, compute_force, compute_motion) and the names of the ship draft file (shipgeom) and path file (shiptrack). The ship model in the example is 9m wide and 46m long. Then set the ship draft file, such as Figure 4 As shown, Notepad is used as a method to open the ship.dep file for setting. In this example, the draft of the ship model at different positions is set in a 9×23 grid, where the draft depth of the bow is set to be smaller to better meet the actual draft of the ship.

[0054] Subsequently, the average number of ships sailing in both directions of the channel at the same time is calculated based on the annual ship throughput table and the average ship speed provided by the project. The specific method is: first, the average number of ships passing through the channel per hour is calculated based on the annual ship throughput; then, the time required for a ship to pass through the model grid area in a single voyage is calculated based on the channel length and ship navigation speed simulated by the model; finally, the ratio of this time to one hour is used to calculate how many ships are sailing in both directions of the model area at the same time. According to calculations in this study area, there are a total of 6 ships in both directions at the same time, three in each direction. Each of the 6 ships must have its ship.txt and track files set up separately, with file numbers 0 to 6, such as Figure 5 , Figure 6 As shown in the figure, the draft of the ship models is the same, so the ship.dep file is not set repeatedly.

[0055] After setting up the ship model, set up the simulated navigation path of the ship. First, select 6 starting points (3 on each side) as the starting points of the 6 ships in the straighter parts of the channel on both sides of the simulation area. Then, set more track points and corresponding times according to the ship's sailing speed to form a closed track. More points should be set in the part where the ship turns, and multiple shorter line segments represent the curved turning part of the navigation track. The track file for setting the ship track is shown below Figure 7 shown.

[0056] Finally, set the parameters of the overall calculation of the model in the param file. The specific parameters are shown in Table 1. After the parameters are set, run the Xbeach.txt file. After running, the corresponding xboutput.nc file is obtained. From the result file, the evolution of the revetment under the long-term action of ship waves can be obtained, such as Figure 8 shown.

[0057] Table 1. Model calculation parameter settings in param file

[0058] Parameter name Settings sedtrans (enable sediment transport calculation) 1 nonh (shallow water equation calculation mode) 1 ships (enable ship wave calculation) 1 tstop (model simulation time / s) 864000 tintg (output time interval / s) 60 D15 (Graded particle size / m) 0.00012 D50 (Graded particle size / m) 0.0002 D90 (Grading particle size / m) 0.00035 <![CDATA[rhos (density / kgm -3 )]]> 2400 … …

[0059] In summary:

[0060] (1) Setting the ship trajectory in a cyclic form can simulate the impact of ship waves caused by multiple ships traveling in the channel for a long time in Xbeach;

[0061] (2) The XBeach model used in the present invention, which sets a cycle path for calculation, can achieve a good simulation effect on the long-term effect of ship waves on the revetment of inland waterways.

[0062] The embodiments are only for illustrating the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the present invention.

Claims

1. A ship wave simulation method based on XBeach ship path loop setting, It is characterized in that The following steps are involved: S1. Use Delft3D combined with engineering drawing interpolation to construct the water depth terrain grid of the experimental simulation area; S2. Set the ship parameters in the ship.txt and ship.dep files of XBeach; S3. Set the loop navigation path data parameters in the track file of Xbeach; S4. Setting the parameters of the XBeach model in the param file of XBeach includes: running time, time step, sediment data and slope coefficient threshold; S5. Use the XBeach model to perform ship wave simulation calculations for ten days, output channel scouring and silting simulation data, and obtain ship wave scouring and silting simulation results; The specific operation of step S1 is as follows: import the channel terrain sample file into Rgfgrid in Grid and bathymetry, draw the terrain boundary according to the scattered distribution of water depth, use the spline function to draw grid lines along the boundary and center line, generate a grid file according to actual needs, wherein the grid of the grid file is a grid with a length of 100 meters and a width of 5 meters, and use the Quickin module and the generated grid file to interpolate the water depth using triangular interpolation and grid averaging methods; The step S2 of setting the ship.txt file specifically includes: firstly setting the size of the unit length dx and the unit width dy of the ship in ship.txt, in meters; then setting the coefficient nx corresponding to the unit length of the ship and the coefficient ny corresponding to the unit width of the ship according to the actual size of the ship, dx×nx and dy×ny are the approximate length and width of the simulated ship size; finally setting the ship's simulated navigation mode, including flying, compute_force and compute_motion, and setting the names of the ship's draft file shipgeom and the path file shiptrack; The step S2 of setting the ship.dep file specifically includes: firstly constructing a grid for simulating the ship according to dx and dy in ship.txt, and then setting the draft of the ship in each grid, wherein the draft of the bow is less than the draft of the stern, and the whole operation is set by using Notepad as a method of opening the ship.dep file; The step S3 sets the closed loop navigation path data parameters in the track file of Xbeach, and the specific contents include: (1) Calculate the number of ships sailing in the waterway at the same time based on the actual ship flow in the waterway; (2) Based on the number of ships calculated in (1), in the water depth terrain grid of the experimental simulation area constructed by S1, positions on both sides of the channel are selected at equal intervals as the starting points of each ship, and all the selected starting points are used to form a closed loop trajectory for the ship's navigation; at the same time, at each turn of this closed loop trajectory, an additional 5 trajectory points are determined, and the time when the ship sails to each trajectory point is calculated based on the actual navigation speed of the ship. The coordinates of all trajectory points and the corresponding time of each ship are respectively input into their respective Xbeach model track files The step S4 sets the model running time, time step, sediment data and slope coefficient threshold in the param file of XBeach, including: (1) In the Physical processes module, set the equations used in the model calculation and start the sediment movement simulation; (2) Set the calculation time step in the Numerics input module; (3) Set various boundary conditions in the Flow boundary condition parameters and Wave boundary condition parameters modules; (4) Set the total simulation time of the model and the time interval model parameters for data output; (5) Set sediment parameters and sediment calculation equation scour simulation parameters; (6) In the Output variables module, set the parameter names to be output and the coordinates of the observation and verification points.

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