A hydrological and hydrodynamic process simulation method based on multiple GPUs

Abstract

The present application relates to the field of hydrological and hydrodynamic simulation, in particular to a hydrological and hydrodynamic process simulation method based on multiple GPUs, comprising the following steps: S1, obtaining basic data and pollutant data of a target area; S2, dividing the target area into a plurality of grid-shaped sub-regions, and assigning a GPU to each sub-region; S3, calculating the water flow data of each sub-region according to the basic data and the pollutant data, the water flow data being used to represent the speed and direction of the water flow; S4, calculating the pollutant concentration at each location at each time according to the water flow data; The present application takes into account the feedback mechanism between biological enrichment and biological degradation, can more accurately predict the pollutant concentration distribution in the water body at different time points, and can better simulate the metabolic process in the organism and the influence of environmental factors, so that the simulation result is closer to the actual situation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydrological and hydrodynamic simulation, and particularly to a hydrological and hydrodynamic process simulation method based on multiple GPUs. BACKGROUND

[0002] When a pollution source appears in a river, lake or ocean, hydrological and hydrodynamic process simulation is a main technical means for simulating the pollution range and pollution concentration at each position, and the common simulation method mainly relies on the simulation of initial conditions and boundary conditions, ignoring the influence of microbial activity (mainly microbial degradation and microbial enrichment) on the concentration of pollutants, which significantly affects the concentration distribution of pollutants in the water body, resulting in that the calculation accuracy of the pollution range and the pollution concentration at each position cannot meet the expected value, and then affecting the efficiency of later sewage treatment. SUMMARY

[0003] In view of the deficiencies of the prior art, the present application provides a hydrological and hydrodynamic process simulation method based on multiple GPUs, which solves the technical problems in the background art.

[0004] To achieve the above purpose, the present application provides the following technical scheme:

[0005] A hydrological and hydrodynamic process simulation method based on multiple GPUs, comprising the following steps:

[0006] S1, obtaining basic data and pollutant data of a target area;

[0007] S2, dividing the target area into a plurality of grid-shaped sub-regions, and assigning a GPU to each sub-region;

[0008] S3, calculating the water flow data of each sub-region according to the basic data and the pollutant data, the water flow data being used to represent the speed and direction of the water flow;

[0009] S4, calculating the pollution concentration at each position at each time according to the water flow data.

[0010] Further, in step S1, the basic data includes terrain elevation, hydrological data, geological data, water body data and meteorological data; the pollutant data includes initial concentration distribution and pollution source information;

[0011] The terrain elevation is used to describe the terrain of the ground surface and the water bottom;

[0012] The geological data is used to describe the soil type and the permeability coefficient;

[0013] The water body data includes the boundary conditions of the water body, the initial water level, the initial water depth and the flow velocity distribution;

[0014] The meteorological data includes wind speed, wind direction and temperature;

[0015] The initial concentration distribution represents the spatial distribution of the pollutant at the initial moment;

[0016] The pollution source information includes the location, emission rate and time sequence of the pollution source.

[0017] Further, in step S3, the following steps are specifically included:

[0018] S31, constructing a coordinate system in the target area with the north-south direction and the east-west direction as the x-axis and the y-axis respectively,

[0019] S32, defining a continuity equation;

[0020] S33, solving the continuity equation according to the basic data to obtain the water depth distribution at the current moment;

[0021] S34, calculating a first influence term and a second influence term for representing other influences on the water flow along the x-axis and y-axis directions according to the basic data;

[0022] S35, defining a momentum equation of the water flow along the x-axis and y-axis directions;

[0023] S36, solving the momentum equation according to the water depth distribution to obtain the water flow direction and flow rate distribution at the next moment;

[0024] S37, repeating the above steps to obtain the water flow data of each sub-region at each moment.

[0025] Further, in step S32, the expression of the continuity equation is:

[0026] ;

[0027] In the formula, denotes the partial derivative; denotes the water depth; denotes the time; denotes the velocity component of the water flow along the x-axis; denotes the velocity component of the water flow along the y-axis direction; denotes the rate of change of the water depth with time; denotes the rate of change of the product of the water flow velocity and the water depth along the x-axis direction; denotes the rate of change of the product of the water flow velocity and the water depth along the y-axis direction.

[0028] Further, in step S34, the first influence term and the second influence term both include friction , Coriolis force and wind stress ;

[0029] wherein the friction force is calculated by the formula:

[0030] ;

[0031] wherein, denotes the density of water; denotes the Manning roughness coefficient; denotes the gravitational acceleration;

[0032] the Coriolis force is calculated by the formula:

[0033] ;

[0034] wherein, denotes the mass density of water; wherein, denotes the Earth rotation angular velocity vector; denotes the dimension;

[0035] the wind stress is calculated by the formula:

[0036] ;

[0037] wherein, denotes the wind drag coefficient; the wind velocity vector ;

[0038] the first influence term and the second influence term are the sum of the friction force , the Coriolis force and the wind stress .

[0039] Further, in step S35, the expressions of the momentum equation are respectively:

[0040] ;

[0041] ;

[0042] wherein, denotes the gravitational acceleration.

[0043] Further, in step S4, specifically comprising the following steps:

[0044] S41, according to the temperature at each moment, and calculate the diffusion coefficient of pollutants , the formula is:

[0045] ;

[0046] wherein, D represents the diffusion coefficient of the pollutant at the reference temperature; ln represents the base of the natural logarithm; E represents the minimum energy required for the diffusion of the pollutant; R represents the ideal gas constant; T represents the reference temperature; T represents the actual temperature;

[0047] S42, obtaining the microbial data of the target area water body and calculating the biodegradation rate and the bioaccumulation rate ;

[0048] S43, calculating the coupling coefficient ;

[0049] S44, constructing the coupling term according to the coupling coefficient , and the calculation formula is:

[0050] ;

[0051] S45, defining the two-dimensional convection-diffusion equation according to the biodegradation rate , the bioaccumulation rate and the coupling term ;

[0052] S46, substituting the water flow data at each time into the two-dimensional convection-diffusion equation and repeating iteration to obtain the pollutant concentration at each position at each time and construct the concentration distribution map.

[0053] Further, in step S42, the calculation formula of the biodegradation rate and the bioaccumulation rate is respectively:

[0054] ;

[0055] ;

[0056] wherein, μ represents the maximum specific growth rate; Ks represents the half-saturation constant; DO represents the dissolved oxygen concentration of the target area water body; Ks represents the oxygen half-saturation constant of the target area water body; K represents the bioaccumulation rate constant; C represents the ratio of the pollutant concentration in the microorganism to the pollutant concentration in the water body; C represents the pollutant concentration of the target area water body; represents the concentration of pollutants in the microorganism.

[0057] Further, in step S43, the coupling coefficient The formula for calculating is:

[0058] ;

[0059] In the formula, represents the speed of the microorganism absorbing pollutants; represents the speed of the microorganism discharging pollutants; represents the maximum concentration of pollutants in the microorganism; represents the minimum concentration of pollutants in the target area water body.

[0060] Further, in step S45, the expression of the two-dimensional convection-diffusion equation is:

[0061] ;

[0062] In the formula, and respectively the biodegradation rate and the bioaccumulation rate.

[0063] Compared with the prior art, the present application provides a hydrological and hydrodynamic process simulation method based on multiple GPUs, which has the following beneficial effects:

[0064] The present application takes into account the feedback mechanism between bioaccumulation and biodegradation, can more accurately predict the concentration distribution of pollutants in the water body at different time points, and can better simulate the metabolic process in the organism and the influence of environmental factors, making the simulation results more close to the actual situation. BRIEF DESCRIPTION OF DRAWINGS

[0065] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0066] Figure 1 is a step flow chart of a hydrological and hydrodynamic process simulation method based on multiple GPUs of the present application. DETAILED DESCRIPTION

[0067] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments. The realization process of how to apply technical means to solve technical problems and achieve technical effects of the present application can be fully understood and implemented.

[0068] Those skilled in the art can understand that all or part of the steps in the following embodiment methods can be completed by instructing the relevant hardware through programs, therefore, the present application can adopt a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) containing computer usable program codes.

[0069] It has important scientific significance and practical application value to simulate the diffusion path and concentration change of pollutants in a water body. For example, when an oil or chemical leakage accident occurs in a water body, the diffusion path and the influence range of the pollutants can be predicted through hydrological and hydrodynamic process simulation, so as to facilitate pollution treatment in the shortest time and avoid further diffusion of the pollution range. For this purpose, as shown in the background art, the present application proposes a hydrological and hydrodynamic process simulation method based on multiple GPUs, including the following steps: Figure 1

[0070] S1, obtaining basic data and pollutant data of a target area; specifically, if the pollution range of a pollution source is to be calculated, the flow direction and flow speed of the corresponding water body need to be calculated, and the soil diffusion degree of the corresponding position also needs to be obtained, therefore, in step S1, the basic data includes terrain elevation, hydrological data, geological data, water body data and meteorological data; the pollutant data includes initial concentration distribution and pollution source information; specifically, the terrain elevation is used to describe the terrain of the ground surface and the water bottom, which can be realized through various ways, at present, the common ones are unmanned aerial vehicle aerial photography or laser radar, the unmanned aerial vehicle aerial photography is to use Pix4D, Agisofe Metashape and other software to perform image stitching and three-dimensional reconstruction, and generate high-resolution terrain elevation; the hydrological data includes rainfall, evaporation and runoff, which can be directly obtained from a meteorological station or a hydrological model; the geological data is used to describe the soil type and the permeability coefficient, which is usually obtained from a geological survey bureau or a relevant research institution; the water body data includes the boundary condition of the water body, the initial water level, the initial water depth and the flow speed distribution, which can be obtained from a geological survey bureau or a relevant research institution; the meteorological data includes wind speed, wind direction and temperature, which can be directly obtained from a meteorological station; the initial concentration distribution represents the spatial distribution of the pollutants at the initial moment, which can be obtained through field monitoring or historical data; the pollution source information includes the position of the pollution source, the emission rate and the time sequence, which is provided by an environmental management department or determined through field investigation.

[0071] ​S2, divide the target area into a plurality of grid-shaped sub-regions, and assign a GPU to each sub-region; specifically, since the hydrological and hydrodynamic model usually involves a large amount of calculation, especially when dealing with high-resolution terrain data and complex water flow dynamics, the multi-GPU system can handle these calculation tasks in parallel, greatly improving the simulation speed, in addition, multi-GPU can optimize the use efficiency of hardware resources, maximize the value of high-performance computing devices.

[0072] S3, calculate the water flow data of each sub-region according to the basic data and the pollutant data, the water flow data being used to represent the speed and direction of the water flow; specifically, since the speed and direction of the water flow will directly affect the pollution range of the pollutant, the speed and direction of the water flow of each sub-region need to be calculated first when calculating the diffusion range of the pollutant, therefore, in step S3, specifically includes the following steps:

[0073] S31, construct a coordinate system in the target area with the north-south direction and the east-west direction as the x-axis and the y-axis respectively,

[0074] S32, define a continuity equation, the expression of which is:

[0075] ;

[0076] In the formula, denotes the partial derivative; denotes the water depth; denotes the time; denotes the velocity component of the water flow along the x-axis; denotes the velocity component of the water flow along the y-axis; denotes the rate of change of water depth with time; denotes the rate of change of the product of water flow velocity and water depth along the x-axis direction; denotes the rate of change of the product of water flow velocity and water depth along the y-axis direction;

[0077] S33, solve the continuity equation according to the basic data to obtain the water depth distribution at the current time;

[0078] S34, calculate a first influence term and a second influence term for representing other factors that will affect the water flow along the x-axis and y-axis directions according to the basic data; specifically, since the collision of water flow will cause the friction between water flows to increase when the water flow converges, in addition, the inertial force caused by the earth's rotation and the wind will affect the water flow, therefore, in step S34, the first influence term and the second influence term both include friction , Coriolis force and wind stress ;

[0079] wherein the friction force is calculated by the formula:

[0080] ;

[0081] wherein, denotes the density of water; denotes the Manning roughness coefficient; denotes the gravitational acceleration; the flow velocity vector ; in the present application, the value range of which is shown in Table 1;

[0082] Table 1:

[0083]

[0084] Coriolis force is calculated by the formula:

[0085] ;

[0086] wherein, denotes the mass density of water; wherein, denotes the earth rotation angular velocity vector; denotes the dimension;

[0087] wind stress is calculated by the formula:

[0088] ;

[0089] wherein, denotes the wind drag coefficient; the wind velocity vector ; in the present application, the value range of which is shown in Table 2;

[0090] Table 2:

[0091]

[0092] the first influence term and the second influence term are the sum of the friction force , the Coriolis force and the wind stress .

[0093] S35, the momentum equations of the water flow along the x-axis and y-axis directions are defined, the expressions of which are respectively:

[0094] ;

[0095] ;

[0096] In the formula, represents the acceleration of gravity;

[0097] S36, according to the water depth distribution, the momentum equation is solved to obtain the water flow direction and flow velocity distribution at the next time;

[0098] S37, repeat the above steps to obtain the water flow data of each sub-region at each time.

[0099] S4, calculate the pollution concentration at each position at each time according to the water flow data; specifically, since the pollution concentration will be affected by microbial degradation, in step S4, the following steps are specifically included:

[0100] S41, calculate the diffusion coefficient of the pollutant according to the temperature at each time , and the calculation formula is:

[0101] ;

[0102] In the formula, represents the diffusion coefficient of the pollutant at the reference temperature; represents the base of the natural logarithm; represents the minimum energy required for the diffusion of the pollutant; represents the ideal gas constant; represents the reference temperature; represents the actual temperature; in the present application, obtained according to the actual type of the corresponding pollutant experiment; 8.314; 25; The value of needs to be determined according to the actual substance, as shown in Table 3;

[0103] Table 3:

[0104]

[0105] S42, obtain the microbial data of the water body in the target area and calculate the biodegradation rate and the biological enrichment rate ; specifically, in step S42, the calculation formulas of the biodegradation rate and the biological enrichment rate are respectively:

[0106] ;

[0107] ;

[0108] In the formula, represents the maximum specific growth rate; represents the half-saturation constant; represents the dissolved oxygen concentration of the water body in the target area; represents the oxygen half-saturation constant of the water body in the target area; represents the biological enrichment rate constant; represents the ratio of the pollutant concentration in the microorganism to the pollutant concentration in the water body; represents the pollutant concentration of the water body in the target area; represents the pollutant concentration in the microorganism; in the present application, , , and can be obtained by laboratory experiments; can be determined by chemical analysis of the biological sample; can be determined by collecting a water sample and performing chemical analysis;

[0109] S43, calculating the coupling coefficient , the calculation formula of which is:

[0110] ;

[0111] In the formula, represents the speed at which the microorganism absorbs the pollutant; represents the speed at which the microorganism discharges the pollutant; represents the maximum pollutant concentration in the microorganism; represents the minimum pollutant concentration in the water body in the target area; in the present application, and are 0.05 and 0.02, respectively; and are obtained by measurement;

[0112] S44, constructing the coupling term according to the coupling coefficient , the calculation formula of which is:

[0113] ;

[0114] S45, defining the two-dimensional convection-diffusion equation according to the biodegradation rate , the biological enrichment rate and the coupling term , the expression of which is:

[0115] ;

[0116] In the formula, and ​The biodegradation rate and the bioaccumulation rate, respectively;

[0117] S46, the water flow data of each time is substituted into the two-dimensional convection-diffusion equation and repeated iteration is carried out, and the pollution concentration of each position at each time is obtained.

[0118] The common method for calculating the pollution concentration of each position of the water body only simulates based on the initial condition and the boundary condition, without considering the influence of the bioaccumulation and the biodegradation on the pollution concentration, in addition, the common calculation method also ignores the metabolic process in the microorganism and the influence on the pollution concentration, so that the simulation result is deviated, the present application considers the feedback mechanism between the bioaccumulation and the biodegradation, can more accurately predict the pollution concentration distribution of the water body at different time points, and can better simulate the metabolic process in the organism and the influence of the environmental factors, so that the simulation result is closer to the actual situation, so as to facilitate the development of the pollution treatment scheme according to it.

[0119] The above embodiments are used to introduce the present application in detail, the principle and the implementation mode of the present application are described by applying specific examples in this paper, the above embodiment is only used to help understand the method of the present application and its core idea; at the same time, for the general technical personnel in the art, according to the idea of the present application, the specific implementation mode and the application range will be changed, according to the above, the content of the specification should not be understood as the limitation of the present application.

Claims

1. A multi-GPU based hydro-hydrodynamic process simulation method, characterized in that, The method comprises the following steps: S1, obtaining basic data and pollutant data of a target area; S2, dividing the target area into a plurality of grid-shaped sub-regions, and assigning a GPU to each sub-region; S3, calculating water flow data of each sub-region according to the basic data and the pollutant data, the water flow data being used to represent the speed and direction of water flow; S4, calculating the pollution concentration at each position at each time according to the water flow data; In step S4, the following steps are included: S41、According to the temperature of each time, and calculate the diffusion coefficient of pollutants The calculation formula is: ； wherein represents the diffusion coefficient of the pollutant at the reference temperature; represents the base of the natural logarithm; represents the minimum energy required for the diffusion of the pollutant; represents the ideal gas constant; represents the reference temperature; represents the actual temperature; S42, obtaining microbial data of the water body in the target region and calculating the biodegradation rate and the bioaccumulation rate ; S43、calculating the coupling coefficient , the coupling coefficient The calculation formula of the coupling coefficient is: ； wherein, represents the rate at which the microorganism absorbs the pollutant; represents the rate at which the microorganism expels the pollutant; represents the maximum pollutant concentration within the microorganism; represents the minimum pollutant concentration in the water body of the target area; S44、According to the coupling coefficient Constructing the coupling term The calculation formula is: ； In the formula, represents the concentration of the pollutant in the water body of the target region; represents the concentration of the pollutant in the microorganism S45, according to the biodegradation rate , the bioaccumulation rate and the coupling term and defining the two-dimensional convection-diffusion equation; S46, substituting the water flow data at each time into a two-dimensional convection-diffusion equation and repeatedly iterating to obtain the pollution concentration at each position at each time and construct a concentration distribution map.

2. The hydrologic-hydrodynamic process simulation method of claim 1, wherein, In step S1, the basic data includes terrain elevation, hydrological data, geological data, water body data and meteorological data; the pollutant data includes initial concentration distribution and pollution source information; The terrain elevation is used to describe the terrain of the ground surface and the water bottom; The geological data is used to describe the soil type and the permeability coefficient; The water body data includes the boundary condition of the water body, the initial water level, the initial water depth and the flow velocity distribution; The meteorological data includes the wind speed, the wind direction and the temperature; The initial concentration distribution represents the spatial distribution of the pollutant at the initial time; The pollution source information includes the position of the pollution source, the emission rate and the time sequence.

3. The hydrologic-hydrodynamic process simulation method of claim 1, wherein, In step S3, the following steps are included: S31, constructing a coordinate system in the target area with the north-south direction and the east-west direction as the x-axis and the y-axis respectively, S32, defining a continuity equation; S33, solving the continuity equation according to the basic data to obtain the water depth distribution at the current time; S34, calculating, from the base data, a first influence term indicative of other factors that would have an influence on the flow of water in the direction of the x-axis and the y-axis and a second influence term ; S35, defining the momentum equation of the water flow along the x-axis and the y-axis directions; S36, solving the momentum equation according to the water depth distribution to obtain the water flow direction and the flow velocity distribution at the next time; S37, repeating the above steps to obtain the water flow data of each sub-region at each time.

4. The hydrologic-hydrodynamic process simulation method of claim 3, wherein, In step S32, the expression of the continuity equation is: ； wherein denotes the partial derivative; denotes the water depth; denotes the time; denotes the velocity component of the water flow along the x-axis; denotes the velocity component of the water flow along the y-axis; denotes the rate of change of the water depth with time; denotes the rate of change of the product of the water flow velocity and the water depth along the x-axis; denotes the rate of change of the product of the water flow velocity and the water depth along the y-axis.

5. The hydrologic-hydrodynamic process simulation method of claim 3, wherein, In step S34, the first influence term and the second influence term each include a friction force , a Coriolis force , and a wind stress ; wherein the friction force is calculated by the formula: ； wherein denotes the density of water; denotes the Manning roughness coefficient; denotes the gravitational acceleration; coriolis force The formula for calculating the Coriolis force is: ； wherein denotes the mass density of water; wherein denotes the earth rotation angular velocity vector; denotes the dimension; wind stress The formula for calculating the wind stress is: ； wherein represents the wind drag coefficient; the wind velocity vector ; a first influence term and a second influence term is the sum of friction forces , coriolis forces and wind stresses .

6. The hydrologic-hydrodynamic process simulation method of claim 4, wherein, In step S35, the expressions of the momentum equations are: ； ； In the formula, g represents the acceleration of gravity.

7. The hydrologic-hydrodynamic process simulation method of claim 1, wherein, In step S42, the biodegradation rate and the bioaccumulation rate are calculated by the following formulas, respectively. ； ； wherein represents the maximum specific growth rate; represents the half-saturation constant; represents the dissolved oxygen concentration of the water body in the target area; represents the oxygen half-saturation constant of the water body in the target area; represents the biological enrichment rate constant; represents the ratio of the pollutant concentration in the microorganism to the pollutant concentration in the water body; represents the pollutant concentration of the water body in the target area; represents the pollutant concentration in the microorganism.

8. The hydrologic-hydrodynamic process simulation method of claim 4, wherein, In step S45, the expression of the two-dimensional convection-diffusion equation is: ； wherein and biodegradation rate and bioaccumulation rate, respectively.

Images