KR102389279B1 - Method and apparatus for constructing tsunami numerical simulation model based on finite element method - Google Patents

Abstract

A method for constructing a tsunami numerical simulation model based on the finite element method is disclosed. The method of the present invention includes the steps of collecting DEM data of the flooding area, constructing a grid system in the flooding area corresponding to the size of the flooding area and the resolution of the DEM data based on preset contour lines on the numerical map, It includes the steps of setting a grid correction region in the grid system based on the seabed topography and location information of past tsunami occurrence points, and determining the optimal resolution of the grid system for each grid correction region using fractal dimensional analysis.

Description

Method and Apparatus for Building Numerical Tsunami Simulation Model Based on Finite Element Method { METHOD AND APPARATUS FOR CONSTRUCTING TSUNAMI NUMERICAL SIMULATION MODEL BASED ON FINITE ELEMENT METHOD }

The present invention relates to a method and apparatus for constructing a numerical simulation model of a tsunami, and more particularly, to a method and apparatus for constructing a numerical simulation model based on a finite element method.

While the frequency and magnitude of earthquakes have increased since the Great East Japan Earthquake in 2011 caused great damage, the lack of national countermeasures, such as the Gyeongju earthquake on September 12, 2016, is increasing public anxiety about earthquakes.

However, it is impossible to respond to various seismic sources and earthquake scales with virtual scenario-based response technology, and to prepare and respond to tsunamis caused by earthquakes, real-time decision-making system is established by providing risk information and securing damage estimation technology across the country. This is an urgent situation.

The existing tsunami response system provided only scenario-based tsunami inundation forecasts, and the technology for real-time tsunami inundation analysis and socio-economic damage estimation due to irregular and frequent undersea earthquakes was absent.

The present invention is to solve the above problems, and an object of the present invention is to construct and optimize a flood simulation model of the finite element method that can resolve the East Sea topographic features, and to efficiently parallelize the tsunami wide area flood numerical model. is to establish

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

A method for constructing a tsunami numerical simulation model based on a finite element method (FEM) according to an embodiment of the present invention includes the steps of collecting DEM (Digital Elevation Model) data of an overflow area, a preset contour line on a numerical map The step of constructing a grid system within the flood area corresponding to the size of the flood area and the resolution of the DEM data based on setting, and determining the optimal resolution of the grid system for each grid correction region using fractal dimensional analysis.

In this case, the past earthquake waveform in the flooding area may be compared with a waveform simulated according to the grid size of the flooding area, and the optimal grid size of the flooding area may be determined according to the comparison result.

In addition, the determining of the optimal resolution includes: preparing a surface area graph indicating the size of the surface area of the correction region according to a difference in grid spacing; extracting a first threshold based on a curve of the surface area graph; 1 may include determining an optimal grid size corresponding to the threshold.

In addition, the method includes the steps of creating an energy graph representing the energy level of the correction region according to the difference in the grid spacing, and extracting a second threshold based on the curve of the energy graph, and corresponding to the extracted second threshold and determining an optimal grid size to be used.

On the other hand, an apparatus for building a tsunami numerical simulation model based on a finite element method (FEM) according to an embodiment of the present invention includes an input unit that receives DEM (Digital Elevation Model) data of an overflow area, and A grid system in the flooding area corresponding to the size of the flooding area and the resolution of the DEM data is configured based on a preset contour line, and based on the subsea topography of the flooding area and location information of past tsunami occurrence points and a processor for setting a grid correction region in the grid system, and determining an optimal resolution of the grid system for each grid correction region by using fractal dimension analysis.

In this case, the processor may compare the past earthquake waveform in the flooding area with a waveform simulated according to the grid size of the flooding area, and determine the optimal grid size of the flooding area according to the comparison result.

In addition, the processor creates a surface area graph indicating the size of the surface area of the correction region according to the difference in grid spacing, extracts a first threshold based on the curve of the surface area graph, and an optimal lattice corresponding to the extracted first threshold size can be determined.

In addition, the processor creates an energy graph indicating the energy level of the correction region according to the difference in the grid spacing, extracts a second threshold based on the curve of the energy graph, and an optimal value corresponding to the extracted second threshold The grid size can be determined.

According to various embodiments of the present invention as described above, the performance of the tsunami wide area flood simulation model can be secured, and it can be used to develop and operate an optimal tsunami wide area flood numerical model including the entire eastern coast.

In order to more fully understand the drawings recited in the Detailed Description, a brief description of each drawing is provided.
1 is a flowchart for briefly explaining a method of constructing a numerical simulation model of a tsunami based on a finite element method according to an embodiment of the present invention;
2 is a view showing a water depth of a demonstration area according to an embodiment of the present invention;
3 is a view showing a finite element method grid network diagram of a demonstration area according to an embodiment of the present invention;
4 is a view showing a tsunami virtual scenario occurrence sea area and major seabed topography of the East Sea according to an embodiment of the present invention;
5 is a view for explaining an example of fractal dimension analysis according to an embodiment of the present invention;
6 is a diagram showing a surface area graph according to a grid mesh diagram and a grid according to an embodiment of the present invention;
7 is a diagram illustrating a grid network diagram of a virtual scenario point and an energy graph according to the grid according to an embodiment of the present invention;
8 is a view showing a wide-area grid network and a water depth according to an embodiment of the present invention;
9 is a view showing an initial waveform of a tsunami in the East Sea tsunami virtual scenario calculated based on the finite element method according to an embodiment of the present invention;
10 is a block diagram schematically illustrating the configuration of an apparatus according to an embodiment of the present invention.

First, terms used in the present specification and claims have been selected in consideration of functions in various embodiments of the present invention. However, these terms may vary depending on the intention of a person skilled in the art, legal or technical interpretation, and emergence of new technology. Also, some terms may be arbitrarily selected by the applicant. These terms may be interpreted in the meanings defined herein, and in the absence of specific definitions, they may be interpreted based on the general content of the present specification and common technical common sense in the art.

Also, the same reference numbers or reference numerals in each drawing appended hereto indicate parts or components that perform substantially the same functions. For convenience of description and understanding, the same reference numbers or reference numerals are used in different embodiments. That is, even though all components having the same reference number are shown in a plurality of drawings, the plurality of drawings do not mean one embodiment.

Also, in this specification and claims, terms including ordinal numbers such as 'first' and 'second' may be used to distinguish between elements. The ordinal number is used to distinguish the same or similar components from each other, and the meaning of the term should not be construed as limited due to the use of the ordinal number. As an example, for components combined with such an ordinal number, the use order or arrangement order should not be construed as being limited by the number. If necessary, each ordinal number may be used interchangeably.

In this specification, the singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as 'comprise' or 'comprise' are intended to designate the existence of a characteristic, number, step, operation, component, part, or combination thereof described in the specification, but one or more other It is to be understood that this does not preclude the possibility of addition or existence of features or numbers, steps, operations, components, parts, or combinations thereof.

In addition, in an embodiment of the present invention, when it is said that a certain part is connected to another part, this includes not only direct connection but also indirect connection through another medium. In addition, the meaning that a certain part includes a certain component means that other components may be further included, rather than excluding other components, unless specifically stated to the contrary.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

The finite element method (FE, finite element method) is a computer simulation model using a numerical technique, and is a model used in a wide range of fields such as continuum mechanics.

The ADCIRC model, which is one of the finite element methods, uses the wave equation expressed as a single equation for water surface displacement by synthesizing the continuity and motion equations of the thousands of equations as the governing equation.

ADCIRC model has been developed for a long time by many researchers, developing the main engine and post-processing codes, and verified its validity through field application. Recently, a realistic numerical model that can deal with practical problems by developing parallel processing codes is being established as

The ADCIRC model, which is a finite element method-based model used in the present invention, is a two- and three-dimensional hydrodynamic model developed over the past 20 years. Currently, as a code, research is being actively carried out to link it in parallel with water quality and ecological models.

1 is a flowchart for briefly explaining a method of constructing a tsunami numerical simulation model based on a finite element method according to an embodiment of the present invention.

First, by collecting DEM (Digital Elevation Model, Numerical Elevation Model) data of the flooded area, it is possible to secure precise elevation and water depth data of the flooded area (S110). Here, DEM data is a general term related to numerical topography or water depth survey data, and is data representing the shape of the topography by storing the elevation value of the topography as a numeric value. DEM data includes information on slope, slope direction, topographic analysis, and the like.

Thereafter, a grid system in the flooding area corresponding to the size of the flooding area and the resolution of the DEM data is constructed based on preset contour lines on the numerical map (S120).

Figure 2 shows the water depth of Sinnam Port, Nogok Port, and Imwon Port, and Figure 3 is a grid system for three pilot areas of Shinnam Port, Imwon Port and Nogok Port, and DEM data, water depth survey data, and the latest coastline data was used to supplement the grid system.

The grid system of the Donghae pilot area was constructed based on the EL.10m contour line using a 1:5,000 scale numerical map. built.

According to the size of the port, the number of grids was composed of 20,183, 101,149, and 10,491 grids in Sinnam Port, Imimwon Port, and Nogok Port, respectively, and the grid size gradually increased outside the flooding station, and the maximum spacing was 40.0m. The constructed flooding area was combined with the grids of the East Sea and the coast of Japan, and a tsunami flooding flood area simulation was performed.

Table 1 below shows the current status of the grid system in the East Sea pilot area.

division New South Port Grid System executive term grid system Nogok Port Grid System number of grids 20,183 101,149 10,491 number of nodes 10,741 50,708 5,708 Minimum spacing (dx) 4.0m 4.0m 4.0m Maximum spacing (dx) 40.0m 40.0m 40.0m

Thereafter, a grid correction region in the grid system is set based on the subsea topography of the flooding area and the location information of the past tsunami occurrence point (S130).

Referring to FIG. 4 , a grid correction area was set by reflecting the location information of major seabed topography and earthquakes in the East Sea. It is possible to calculate the lattice correction area that reflects the Uljin-Samcheok submarine topography (41), the submarine topography near the Great Basin (42), 11 hypothetical tsunami scenarios, and the location information (43) of the point where the past Japanese tsunami (1983, 1993) occurred. there is.

The Uljin-Samcheok submarine topography is a bifurcated underwater mountain range, showing the shape from the Uljin and Samcheok coasts to the distant East Sea, respectively. In the 11 hypothetical tsunami scenarios, as the number increases from 1 to 11, the location moves from the south to the north of the coast of Japan. In this case, the grid size may be modified in consideration of the earthquake initial waveform according to the location of the earthquake.

Table 2 below shows the location information of the tsunami virtual scenario, and Table 3 shows the location information of the past tsunami in Japan.

No. Location Orient Latitude (°N) Longitude (°E) One 37.5 137.5 0.0 2 38.3 137.7 14.5 3 39.0 138.0 27.5 4 39.7 138.4 17.0 5 40.2 138.7 10.0 6 40.9 138.9 1.0 7 41.7 139.0 1.0 8 42.1 139.1 4.0 9 42.9 139.1 2.0 10 43.5 139.2 2.0 11 44.4 139.2 3.0

No. Location note Latitude (°N) Longitude (°E) 1983 38.74 139.42 40.21 138.84 1993 40.54 139.02 42.34 139.25 43.12 139.40

Thereafter, the optimal resolution of the grid system for each grid correction region is determined using fractal dimension analysis (S140).

In this case, a surface area graph indicating the size of the surface area of the correction region according to the difference in grid spacing may be prepared, a threshold value may be extracted based on a curve of the surface area graph, and an optimal grid size corresponding to the extracted threshold may be determined.

Specifically, the grid correction for each region can be performed by fractal dimensional analysis to improve the optimal resolution of the grid system. The size of the surface area according to the dx difference that develops the topography can be drawn on a graph, and the optimal dx of the correction area can be selected based on the curve of the graph. Here, dx may represent a grid spacing or a grid size.

The process of estimating the optimal dx is i) creating a graph with the size of dx on the x-axis and the surface area of the y-axis as the surface area of the correction region, ii) The economically optimal optimal The step of selecting dx, iii) as shown in FIG. 5 , using the location information of X, Y, and Z of the three grid points, may include a step of calculating the area of a triangle by using a vector dot product. In FIG. 5 , a is the area of each grid calculated by using the vector dot product, A is the total area of the flooding area, and D _m is the dimension of the fractal.

At this time, as shown in FIG. 6 , through the process of fractal dimensional analysis, it is possible to select a threshold value in the surface area (A)-dx graph to select the optimal grid size of the large mound that can express the seabed topography. Fig. 6 (a) is a grid diagram of the large mound, and (b) is a graph of the surface area according to the grid of the large mound.

After that, it is possible to find the threshold in the energy (E)-dx graph and select the optimal grid size of the virtual scenario point that can appropriately implement the initial waveform of the tsunami.

Specifically, an energy graph indicating the energy level of the correction region according to the difference in grid spacing may be created, a threshold value may be extracted based on a curve of the energy graph, and an optimal grid size corresponding to the extracted threshold may be determined.

In the example shown in FIG. 7 , as a result of examining the water depth and energy graph, the optimal dx of the surface area (A)-dx graph was 800 m, and the optimal dx of the energy (E)-dx graph was 1,000 m.

In order to calculate the optimal dx for water depth and initial water level, grid sizes can be selected for the Great Basin, Samcheok-Uljin, tsunami hypothetical scenarios, past earthquakes, and domestic earthquake occurrence regions. When a detailed grid of major topography and historical and domestic earthquake occurrence points is transplanted into an existing grid system, refraction and reflection due to differences in grid size may affect tsunami propagation. m or less.

division selection
size
(m) number of grids number of nodes note before modification after modification before modification after modification chatter depth of water 800 10,007 228.394 5,137 114,255

East Sea
1.0km
sub grid
by size
Configuration
domestic earthquake
generation area 1,000 8,686 213,870 4,137 107,029 Samcheok to Uljin 1,000 8,325 575,509 4,310 287,902 Tsunami Hypothetical Scenarios and Past Earthquakes Early
waveform 1,000 18,310 174,100 9,257 87,260

8 is a view showing a wide-area grid network and a water depth according to an embodiment of the present invention.

Stabilization and optimization of the grid system were performed through iterative calculations of past historical earthquakes (1983, 1993) for a wide-area grid network.

At this time, the grid system can be stabilized and optimized by comparing the past earthquake waveform in the flooded area with the simulated waveform according to the grid size of the flooding area, and determining the optimal grid size of the flooding area according to the comparison result. there is.

In order to examine the appropriateness of the grid of the East Sea region finally composed of less than 1.0 km, spatial wave propagation according to time by configuring the grid size of 1.0 km, 2.0 km, 5.0 km, 8.0 km, and 10.0 km for the East Sea region, The grid system can be compared by comparing waveforms at major points (Imwon, Mukho, Sokcho, and Pohang).

As a result of comparing waveforms for past historical earthquakes (1983, 1993), the level of the waveform increased as the grid size decreased. For this purpose, it was confirmed that a grid of 1.0 km is suitable.

9 is a diagram illustrating an initial waveform of a tsunami in a hypothetical East Sea tsunami scenario in which calculations are performed based on the finite element method according to an embodiment of the present invention.

The finite element method-based model was calculated by increasing the moment scale (M _w ) from 7.5 to 8.5 in 0.5 increments for 11 hypothetical scenarios.

9 is an example showing the initial waveform of the tsunami in the hypothetical scenarios of case 1 and case 5. As the number increases, the virtual scenario moves from the south to the north of the coast of Japan, and as the magnitude of the moment increases, the range of the waveform increases to the east and north.

The calculation of the moment scale (M _w ) 7.5 was performed with a finite element method-based model for 11 hypothetical scenarios, and the FDM (Finite Difference Method) model time series and the maximum tidal level of major ports such as Imwon Port, Mukho Port, and Sokcho Port were calculated. can be compared It was found that the hypothetical scenario reached the east coast later from case 1 to case 11, and reached the east coast in about 105 minutes in case 1 and 125 minutes in case 11.

10 is a block diagram schematically illustrating the configuration of an apparatus according to an embodiment of the present invention.

As shown in FIG. 10 , the apparatus 100 for building a numerical simulation model of the present invention includes an input unit 110 and a processor 120 .

The input unit 110 is configured to receive DEM (Digital Elevation Model) data of the flooding area.

The processor 120 configures a grid system within the flooding area corresponding to the size of the flooding area and the resolution of the DEM data based on the preset contour lines on the numerical map, and location information of the subsea topography of the flooding area and the over-flood tsunami occurrence point Based on , the grid correction area in the grid system is set. Thereafter, the processor 120 determines the optimal resolution of the grid system for each grid correction area by using the fractal dimension analysis.

In addition, the processor 120 may compare the past earthquake waveform in the flooding area with a simulated waveform derived from the grid size of the flooding area, and determine the optimal grid size of the flooding area according to the comparison result.

In addition, the processor 120 may create a surface area graph indicating the size of the surface area of the correction region according to the difference in grid spacing, extract a threshold based on the curve of the surface area graph, and determine an optimal grid size corresponding to the extracted threshold. there is.

In addition, the processor 120 may create an energy graph indicating the energy level of the correction region according to the difference in grid spacing, extract a threshold based on the curve of the energy graph, and determine an optimal grid size corresponding to the extracted threshold. .

According to various embodiments of the present invention as described above, the performance of the tsunami wide area flood simulation model can be secured, and it can be used to develop and operate an optimal tsunami wide area flood numerical model including the entire eastern coast.

In addition, the method according to the above-described various embodiments may be implemented as a program and stored in various recording media. That is, a computer program that is processed by various processors to execute the above-described method may be used in a state stored in a recording medium.

As an example, i) collecting DEM data of the flooding area, ii) configuring a grid system in the flooding area corresponding to the size of the flooding area and the resolution of the DEM data based on preset contour lines on the numerical map, iii) ) setting the grid correction area in the grid system based on the seabed topography of the flooding area and the location information of past tsunami occurrence points; A non-transitory computer readable medium in which a program for performing the steps is stored may be provided.

The non-transitory readable medium refers to a medium that stores data semi-permanently, rather than a medium that stores data for a short moment, such as a register, cache, memory, and the like, and can be read by a device. Specifically, the above-described various applications or programs may be provided by being stored in a non-transitory readable medium such as a CD, DVD, hard disk, Blu-ray disk, USB, memory card, ROM, and the like.

On the other hand, although preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention pertains without departing from the gist of the present invention as claimed in the claims In addition, various modifications are possible by those of ordinary skill in the art, and these modifications should not be individually understood from the technical spirit or perspective of the present invention.

S110: Collecting DEM data of the flooded area
S120: A step of constructing a grid system in the flooding area corresponding to the size of the flooding area and the resolution of the DEM data based on the preset contour lines on the numerical map
S130: Setting a grid correction area in the grid system based on the subsea topography of the flooding area and the location information of past tsunami occurrence points
S140: Determining the optimal resolution of the grid system for each grid correction area using fractal dimensional analysis
100: numerical simulation model building device 110: input unit
120: processor

Claims (9)

delete delete delete delete In an apparatus for building a tsunami numerical simulation model based on a finite element method (FEM),
an input unit for receiving DEM (Digital Elevation Model) data of the flooded area; and
Based on the preset contour line on the numerical map, a grid system in the flooding area corresponding to the size of the flooding area and the resolution of the DEM data is constructed, and the subsea topography of the flooding area and the location of the occurrence point of the tsunami virtual scenario A processor that sets a grid correction region in the grid system based on information and location information of past tsunami occurrence points, and determines the optimal resolution of the grid system for each grid correction region using fractal dimensional analysis;
The grid system in the flood zone includes information on the number of grids, the number of nodes, the minimum spacing, and the maximum spacing,
The processor is
The grid size is corrected in consideration of the initial waveform of the earthquake according to the location of the earthquake,
The processor is
creating a surface area graph indicating the size of the surface area of the grid correction region according to the difference in grid spacing, extracting a first threshold based on the curve of the surface area graph, and determining an optimal grid size corresponding to the extracted first threshold, ,
The processor is
Create an energy graph indicating the energy level of the grid correction region according to the difference in grid spacing, extract a second threshold based on the curve of the energy graph, and determine the optimal grid size corresponding to the extracted second threshold device to do.
delete delete delete delete

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