CN113779671B - Open channel water transfer engineering hydrodynamic force real-time calculation method based on space-time step length self-adaptive technology - Google Patents

Open channel water transfer engineering hydrodynamic force real-time calculation method based on space-time step length self-adaptive technology Download PDF

Info

Publication number
CN113779671B
CN113779671B CN202110997426.9A CN202110997426A CN113779671B CN 113779671 B CN113779671 B CN 113779671B CN 202110997426 A CN202110997426 A CN 202110997426A CN 113779671 B CN113779671 B CN 113779671B
Authority
CN
China
Prior art keywords
flow
step length
calculation
space
water
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110997426.9A
Other languages
Chinese (zh)
Other versions
CN113779671A (en
Inventor
张召
雷晓辉
李月强
查桓
刘玉敏
陈广明
宋有权
朱杰
景象
王艺霖
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anhui Provincial Group Ltd For Yangtze To Huaihe Water Diversion
China Institute of Water Resources and Hydropower Research
Original Assignee
Anhui Provincial Group Ltd For Yangtze To Huaihe Water Diversion
China Institute of Water Resources and Hydropower Research
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Anhui Provincial Group Ltd For Yangtze To Huaihe Water Diversion, China Institute of Water Resources and Hydropower Research filed Critical Anhui Provincial Group Ltd For Yangtze To Huaihe Water Diversion
Priority to CN202110997426.9A priority Critical patent/CN113779671B/en
Publication of CN113779671A publication Critical patent/CN113779671A/en
Application granted granted Critical
Publication of CN113779671B publication Critical patent/CN113779671B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/10—Geometric CAD
    • G06F30/13—Architectural design, e.g. computer-aided architectural design [CAAD] related to design of buildings, bridges, landscapes, production plants or roads
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Evolutionary Computation (AREA)
  • General Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Computational Mathematics (AREA)
  • Mathematical Analysis (AREA)
  • Mathematical Optimization (AREA)
  • Pure & Applied Mathematics (AREA)
  • Management, Administration, Business Operations System, And Electronic Commerce (AREA)

Abstract

The invention discloses a real-time calculation method for the hydrodynamic force of an open channel water transfer project based on a space-time step self-adaptive technology, which comprises the steps of S1, constructing a hydrodynamic force simulation model based on a holy-Vietnam equation set; s2, setting internal and external boundary conditions of the channel based on the constructed hydrodynamic simulation model, S3, setting different time step lengths based on the constructed hydrodynamic simulation model, calculating and obtaining a space step length adaptive to the time step length, and determining a change rule of the space step length along with the time step length; s4, setting different time steps based on the constructed hydrodynamic simulation model, calculating to obtain the calculation running time corresponding to the different time steps, and determining the change rule of the calculation running time along with the time steps and the space steps. The advantages are that: the method can obtain the relation between the calculation time step and the calculation efficiency on the basis of the space-time step self-adaptive relation, and effectively improves the efficiency of the hydrodynamic real-time calculation of the open channel water transfer engineering.

Description

Open channel water transfer engineering hydrodynamic force real-time calculation method based on space-time step length self-adaptive technology
Technical Field
The invention relates to the technical field of one-dimensional hydrodynamic real-time calculation, in particular to a real-time calculation method for open channel water transfer engineering hydrodynamic based on a space-time step length self-adaptive technology.
Background
Along with the development of social economy, the demand of people for water resources is increasing, and water transfer engineering becomes an important means for solving the problem of social water resource shortage, optimizing the water resource configuration pattern and improving the regional water supply guarantee capacity. The water transfer mode comprises two main types of non-pressure open channel water delivery and pressure pipeline water delivery. The open channel water delivery has the advantages of small project investment, low operating cost, large water delivery flow and convenient construction, so the open channel water delivery is widely applied to water transfer projects at home and abroad. In recent years, with the continuous development of large-scale water diversion projects, open channel water diversion gradually tends to the dispatching characteristics of long distance, multiple fluctuation, multiple gate groups and the like.
In actual water transfer projects, the real-time calculation problem of water power with continuously changing upstream and downstream boundary conditions exists in most cases. The traditional hydrodynamic real-time calculation is based on dispersion and linearization of the Saint-Venn equation, the space step length is divided, the time step length is determined at first, and then the result is converged by adjusting the time step length in the calculation. The relative relationship between the time step and the space step is generally expressed by a coulomb number (count number), and is used to adjust the stability and convergence of the calculation. Generally, as the kuran number changes from small to large, the convergence rate gradually increases, but the stability gradually decreases. Therefore, in the specific calculation process, the number of the kuronan is usually set from small, the size is properly adjusted by referring to the convergence condition of the iteration residual, and finally a proper value is found, so that the convergence speed is high enough, and the stability of the convergence speed can be ensured.
However, this method has certain disadvantages, on one hand, the kurong value is not easy to determine, and on the other hand, because the space grid step length and the time grid step length are not definite, the divergence and non-convergence conditions are likely to occur in the calculation process, so that the calculation cannot be completed, and the time step length needs to be reduced under the divergence condition, the smaller the time step length is, the lower the calculation rate is, and the real-time requirement of the system may not be met.
Disclosure of Invention
The invention aims to provide a real-time calculation method for the hydrodynamic force of open channel water transfer engineering based on a space-time step length self-adaptive technology, so that the problems in the prior art are solved.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a real-time calculation method of open channel water transfer engineering water power based on space-time step length self-adaptive technology comprises the following steps,
s1, constructing a hydrodynamic simulation model based on the Saint-Vietnam equation set;
s2, setting internal and external boundary conditions of the channel based on the constructed hydrodynamic simulation model,
s3, setting different time step lengths based on the constructed hydrodynamic simulation model, calculating and obtaining a space step length adaptive to the time step length, and determining the change rule of the space step length along with the time step length;
s4, setting different time step lengths based on the constructed hydrodynamic simulation model, calculating to obtain the calculation operation time corresponding to the different time step lengths, and determining the change rule of the calculation operation time along with the time step length and the space step length.
Preferably, the system of equations includes a continuity equation and a momentum equation,
the equation of continuity is as follows,
Figure BDA0003234317610000021
the momentum equation is as follows,
Figure BDA0003234317610000022
wherein B is the width of the surface of the water passing section; z is water level; t is time; q is the flow; x is the channel longitudinal distance along the main flow direction; q is a side inflow; alpha is a momentum correction coefficient; a is the water passing area(ii) a g is the acceleration of gravity; sfThe calculation formula for the friction drag ratio is as follows,
Figure BDA0003234317610000023
wherein n iscThe Manning roughness coefficient of the water delivery channel; and R is the hydraulic radius.
Preferably, the channel inner and outer boundary conditions are an inner boundary condition and an outer boundary condition respectively, the outer boundary condition includes an upstream boundary condition and a downstream boundary condition, the upstream boundary condition includes a water level boundary and a flow rate boundary, and the downstream boundary condition includes a water level boundary, a flow rate boundary and a water level-flow rate relation boundary; the inner boundary condition is a node with obviously changed hydraulic characteristics or geometric shapes in the water delivery system, and comprises a check gate and a water diversion port.
Preferably, for the outer boundary conditions, assuming that the open channel water transfer project contains Ns sections, the whole water delivery system contains 2Ns unknowns, namely Ns water levels and Ns flow rates, and the solution of the hydrodynamic simulation model also needs 2Ns mutually independent equations; since Ns sections generate Ns-1 buildings in total, i.e., there are 2Ns-2 governing equations, it is necessary to supplement the upstream boundary conditions and the downstream boundary conditions to form a closed system of equations.
Preferably, aiming at the inner boundary condition, a check gate in the open channel water transfer project belongs to a low-water-head water and soil building, and the flow calculation adopts a calculation method of a wide top weir; because the flow formulas are different under different outflow conditions, the outflow state of the weir gate is firstly determined before the formula is selected;
the method for discriminating the water flow field of the weir gate is that when hs/H0>0.8 hour is submerged discharge, hs/H0When the flow rate is less than or equal to 0.8, the flow is free outflow; when e/H>Weir flow is set when the flow rate is 0.65, and hole flow is set when the e/H is less than or equal to 0.65;
wherein H is weir water head, H is Zi-Zb；H0The weir upper total head comprising the near velocity head,
Figure BDA0003234317610000031
v0the current velocity is determined; e is the opening degree of the brake hole; h issWater depth after the gate hs＝Zi+1-Zb；ZbIs the weir crest elevation; ziControlling the water level of the cross section in front of the gate; zi+1Controlling the water level of the cross section after the gate;
when the check gate is in a free outflow state, the flow of the passing gate is not influenced by the downstream water level, and the relation between the upstream water level and the downstream water level of the check gate cannot be directly established through a check gate flow formula; therefore, the check gate is under the condition of free outflow, and the check gate, the upstream and the downstream are automatically divided into two single channels for processing; aiming at an upstream channel, calculating to obtain the front section water level Z of the check gate by taking a check gate flow formula as a downstream boundary conditioniSum flow rate QiAnd according to the continuous equation, the flow Q of the front section of the gateiFlow Q delivered to rear section of gatei+1Determining an upstream boundary condition of a downstream channel;
the flow rate in the case of free orifice flow is formulated as,
Figure BDA0003234317610000032
the flow equation in the case of free weir flow is expressed as,
Figure BDA0003234317610000033
wherein M is1And M2Respectively representing the integrated flow coefficient in the case of free-bore flow and free-weir flow, BgIn order to control the total width of the sluice water;
when the check gate is in a submerged outflow state, the relation between the upstream and downstream water levels and the flow of the check gate can be established through a flow formula; in this case, the water delivery system comprising the check gates can be solved as a whole;
the flow equation for the case of submerged orifice flow is expressed as,
Figure BDA0003234317610000041
wherein M is3In order to submerge the comprehensive flow coefficient under the hole flow, the Taylor expansion method is adopted to carry out linear processing on the formula (6), the second order and the above terms are ignored, and the following form can be written,
Figure BDA0003234317610000042
the formula (7) can be rewritten as,
Figure BDA0003234317610000043
in this case, the linearization coefficients of the governing equation of the throttling gate flow formula are respectively,
Figure BDA0003234317610000044
the flow equation for the submerged weir flow case is expressed as,
Figure BDA0003234317610000045
in the formula, M4In order to submerge the comprehensive flow coefficient under the weir flow, Taylor expansion method is adopted to carry out linear processing on the formula (9), the second order and above terms are ignored, and the following form can be written,
Figure BDA0003234317610000046
in this case, the linearization coefficients of the governing equation of the throttling gate flow formula are respectively,
Figure BDA0003234317610000047
preferably, step S3 is specifically to control a phase error caused by numerical dispersion by reasonably matching the time step Δ t and the space step Δ x, so as to improve the stability of the hydrodynamic simulation model; get
Figure BDA0003234317610000048
That is, Δ x is automatically divided according to the set Δ t, h0Calculating the initial water depth of the downstream control section of the channel section; setting the length of the whole channel as L, dividing the channel into n sections according to a formula n-L/delta x in the calculation and operation process of the hydrodynamic simulation model, and if n is an integer, keeping delta x unchanged; if n is not an integer, the segment becomes n +1 segment
Δx＝L/(n+1) (12)
According to the relation between the space step length and the time step length, in the actual calculation process, when the set time step length is adjusted, the space step length calculated by the hydrodynamic simulation model is correspondingly changed.
Preferably, step S4 specifically includes the following steps,
s41, determining the relation between the space-time step length and the calculation efficiency; based on a hydrodynamic simulation model, respectively determining space step length and calculation operation time under different time step lengths, and analyzing the change trends of the space step length and the calculation operation time under different space-time step lengths to obtain the time step length with the highest calculation efficiency;
s42, determining the relation between the calculation time step and the calculation precision; based on the hydrodynamic simulation model, the space step length under different time step lengths and the absolute error between the calculated value of the water level before each check gate and the measured value are respectively determined, and the relation between the calculated time step length and the calculation precision can be obtained.
The invention has the beneficial effects that: 1. the method determines the self-adaptive relationship between the time step length and the space step length in the hydrodynamic real-time calculation process of the open channel water transfer engineering, reduces the step length trial and error times caused by result divergence in the calculation, and is more convenient to operate compared with the traditional method for simultaneously giving the time step length and the space step length. 2. The method can obtain the relation between the calculation time step and the calculation efficiency on the basis of the space-time step self-adaptive relation, and effectively improves the efficiency of the hydrodynamic real-time calculation of the open channel water transfer engineering.
Drawings
FIG. 1 is a schematic logic diagram of a method for hydrodynamic real-time computation in an embodiment of the present invention;
FIG. 2 is a schematic view of the wide top weir gate outflow in an embodiment of the present invention;
FIG. 3 is a schematic diagram of the upstream and downstream boundaries of a Jingshi section in an embodiment of the present invention;
FIG. 4 is a schematic diagram of the regulating process of the check gate of the Jingshi section in the embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating a relationship between a time step and a space step of each channel calculated based on the method of the present invention in the embodiment of the present invention;
fig. 6 is a schematic diagram of a relationship between a time step calculated based on the method of the present invention and a calculation run time in the embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Example one
As shown in fig. 1, in the present embodiment, a method for computing hydrodynamic force of open channel water diversion engineering in real time based on space-time step length adaptive technique is provided, which includes the following steps,
s1, constructing a hydrodynamic simulation model based on the Saint-Vietnam equation set;
s2, setting internal and external boundary conditions of the channel based on the constructed hydrodynamic simulation model,
s3, setting different time step lengths based on the constructed hydrodynamic simulation model, calculating and obtaining a space step length adaptive to the time step length, and determining the change rule of the space step length along with the time step length;
s4, setting different time step lengths based on the constructed hydrodynamic simulation model, calculating to obtain the calculation operation time corresponding to the different time step lengths, and determining the change rule of the calculation operation time along with the time step length and the space step length.
In the embodiment, the open channel water transfer engineering hydrodynamic real-time calculation method based on the space-time step length adaptive technology provided by the invention can ensure the calculation precision and obviously improve the calculation efficiency. The method mainly constructs the self-adaptive relationship between a time step length and a space step length according to the relation between the time step length and the space step length in the modeling of the hydrodynamic real-time calculation model (and the hydrodynamic simulation model), and balances the relationship between the time step length and the space step length and the calculation efficiency and the calculation precision, thereby providing a new idea for improving the real-time calculation efficiency of the hydrodynamic in the open channel water transfer engineering. The method specifically comprises four parts which are respectively as follows: establishing a hydrodynamic simulation model, setting conditions of the inner boundary and the outer boundary of a channel, determining the adaptive relation of time step length and space step length, and determining the relation of space-time step length, calculation efficiency and calculation precision. These sections are described in detail below.
Establishing hydrodynamic simulation model
This portion corresponds to step S1; in open channel water transfer projects, the length of the water transfer system is far greater than the width and depth of a water transfer section, so that a hydrodynamic simulation model of the water transfer system can be approximately summarized into a one-dimensional problem. The basic control equation of the one-dimensional water flow movement of the channel is a Saint-Vinan equation set, and the equation set comprises a continuous equation and a momentum equation;
the equation of continuity is as follows,
Figure BDA0003234317610000061
the momentum equation is as follows,
Figure BDA0003234317610000062
wherein B is the width of the surface of the water passing cross section, m; z is water level, m; t is time, s; q is the flow，m3S; x is the longitudinal channel distance in the main flow direction, m; q is a side inflow, m3S; alpha is a momentum correction coefficient; a is the water passing area, m2(ii) a g is the acceleration of gravity, m/s2；SfThe calculation formula for the friction drag ratio is as follows,
Figure BDA0003234317610000071
wherein n iscThe Manning roughness coefficient of the water delivery channel; r is hydraulic radius, m.
Second, determining the internal and external boundary conditions of the channel
This portion corresponds to step S2; the channel boundary conditions comprise inner boundary conditions and outer boundary conditions, the outer boundary conditions comprise upstream boundary conditions and downstream boundary conditions, the upstream boundary conditions comprise water level boundaries and flow boundaries, and the downstream boundary conditions comprise water level boundaries, flow boundaries and water level-flow relation boundaries; the inner boundary condition is a node in the water delivery system where the hydraulic characteristics or the geometric shape change obviously, including a check gate, a water diversion port and the like.
Aiming at the outer boundary condition, assuming that the open channel water transfer project contains Ns sections, the whole water transmission system contains 2Ns unknowns, namely Ns water levels and Ns flow rates, and the solution of the hydrodynamic simulation model also needs 2Ns mutually independent equations; since Ns sections generate Ns-1 buildings in total, i.e., there are 2Ns-2 governing equations, it is necessary to supplement the upstream boundary conditions and the downstream boundary conditions to form a closed system of equations.
Aiming at the condition of an inner boundary, a check gate in open channel water transfer engineering belongs to a low-water-head water and soil building, and the flow calculation adopts a calculation method of a wide top weir; the gate hole outflow diagram on the wide top weir shown in fig. 2; in the figure, H is weir water head, and H is Zi-Zb；H0The weir upper total head comprising the near velocity head,
Figure BDA0003234317610000072
v0the current velocity is determined;e is the opening degree of the brake hole; h issWater depth after the gate hs＝Zi+1-Zb；ZbIs the elevation of the weir crest; ziControlling the water level of the cross section in front of the gate; zi+1For controlling the water level of the section after the gate, r is the radius of the radial gate, hcWater depth is the shrinkage cross section; the variable units are m. Because the flow formula is different under different outflow conditions, the outflow state of the weir gate should be determined before the formula is selected.
The method for discriminating the water flow field of the weir gate is that when hs/H0>0.8 hour is submerged discharge, hs/H0When the flow rate is less than or equal to 0.8, the flow is free outflow; when e/H>Weir flow is set when the flow rate is 0.65, and hole flow is set when the e/H is less than or equal to 0.65;
when the check gate is in a free outflow state, the flow of the passing gate is not influenced by the downstream water level, and the relation between the upstream water level and the downstream water level of the check gate cannot be directly established through a check gate flow formula; therefore, under the condition of free outflow, the throttle gate, the upstream and the downstream are automatically divided into two single channels for processing; aiming at an upstream channel, a flow formula of the check gate is used as a downstream boundary condition (namely a water level-flow relation boundary), and the front section water level Z of the check gate is obtained by calculationiSum flow rate QiAnd according to the continuous equation, the flow Q of the front section of the gateiTo the post-gate cross-sectional flow Qi+1Determining an upstream boundary condition (flow boundary) of a downstream channel;
the flow rate in the case of free orifice flow is formulated as,
Figure BDA0003234317610000081
the flow equation in the case of free weir flow is expressed as,
Figure BDA0003234317610000082
wherein M is1And M2Respectively representing the integrated flow coefficient in the case of free-bore flow and free-weir flow, BgTo control the total width of the sluice water.
When the check gate is in a submerged outflow state, the relation between the upstream and downstream water levels and the flow of the check gate can be established through a check gate flow formula; in this case, the water delivery system comprising the check gates can be solved as a whole;
the flow equation for the case of submerged orifice flow is expressed as,
Figure BDA0003234317610000083
wherein M is3In order to submerge the comprehensive flow coefficient under the hole flow, the Taylor expansion method is adopted to carry out linear processing on the formula (6), the second order and the above terms are ignored, and the following form can be written,
Figure BDA0003234317610000084
the formula (7) can be rewritten as,
Figure BDA0003234317610000085
in this case, the linearization coefficients of the governing equation of the throttling gate flow formula are respectively,
Figure BDA0003234317610000086
Gi＝1；
Figure BDA0003234317610000087
the flow equation for the submerged weir flow case is expressed as,
Figure BDA0003234317610000088
in the formula, M4In order to submerge the comprehensive flow coefficient under weir flow, linear treatment is carried out on the formula (9) by adopting a Taylor expansion method, and the second order is ignoredAnd the foregoing, may be written in the form of,
Figure BDA0003234317610000091
in this case, the linearization coefficients of the governing equation of the throttling gate flow formula are respectively,
Figure BDA0003234317610000092
Gi＝1；
Figure BDA0003234317610000093
comprehensive flow coefficient M in flow formula1、M2、M3、M4Closely related to the weir gate form, operating conditions, and building characteristics.
Third, determining the adaptive relation between the time step and the space step
This portion corresponds to step S3; in the traditional hydrodynamic real-time calculation grid step length determination, a space step length and a time step length are generally determined independently in sequence, the situation of non-convergence is easily generated in the calculation process, and then the calculation efficiency is easily reduced in the process of returning to the step length reduction calculation, so that the phase error generated by numerical value dispersion can be controlled through reasonable collocation of the time step length delta t and the space step length delta x, and the stability of a hydrodynamic simulation model is further improved; the invention is to get
Figure BDA0003234317610000094
That is, Δ x is automatically divided according to the set Δ t, h0Calculating the initial water depth of the downstream control section of the channel section; setting the length of the whole channel as L, dividing the channel into n sections according to a formula n-L/delta x in the calculation and operation process of the hydrodynamic simulation model, and if n is an integer, keeping delta x unchanged; if n is not an integer, the segment becomes n +1 segment
Δx＝L/(n+1) (12)
According to the relation between the space step length and the time step length, in the actual calculation process, when the set time step length is adjusted, the space step length calculated by the hydrodynamic simulation model is correspondingly changed.
Fourthly, determining the relation between the space-time step length and the calculation efficiency and the calculation precision
The part corresponds to step S4, and the space step, the calculation running time, and the calculation error under different time step conditions can be respectively determined through the constructed hydrodynamic simulation model, and the time step result with the highest calculation efficiency and the calculation accuracy can be obtained by analyzing the change trends of the space step, the calculation running time, and the calculation accuracy under different space-time steps. Specifically, step S4 specifically includes the following steps,
s41, determining the relation between the space-time step length and the calculation efficiency; based on a hydrodynamic simulation model, respectively determining space step length and calculation operation time under different time step lengths, and analyzing the change trends of the space step length and the calculation operation time under different space-time step lengths to obtain the time step length with the highest calculation efficiency;
s42, determining the relation between the calculation time step and the calculation precision; based on the hydrodynamic simulation model, the space step length under different time step lengths and the absolute error between the calculated value of the water level before each check gate and the measured value are respectively determined, and the relation between the calculated time step length and the calculation precision can be obtained.
Example two
In this embodiment, taking a section from the water transfer engineering ancient canal regulation gate to the north refusal regulation gate (referred to as "beijing stone section" for short) as an example, the method described in the present invention is used to construct and calculate a hydrodynamic real-time calculation model, and analyze and calculate a relationship between a time step and calculation efficiency.
The total length of the engineering is 1432 km, wherein the total length of the Jingshi section is 227km, the buildings along the line comprise 14 regulating gates, 13 water distribution openings, 12 water discharge gates, 17 sections of inverted siphons, 108 sections of gradual change sections and 130 sections of channels, and the channel length information is shown in table 1. The method uses a space-time step length self-adaptive technology, improves the calculation efficiency while meeting the calculation precision requirement, and supports the real-time calculation of the hydrodynamic force. The specific implementation steps are as follows:
TABLE 1 channel length information Table
Figure BDA0003234317610000101
Figure BDA0003234317610000111
Establishing hydrodynamic simulation model
And constructing a one-dimensional hydrodynamic simulation model based on the Saint-Venn equation set, and adopting the space-time step length self-adaptive technology provided by the invention in the model. And (4) performing hydrodynamic simulation on a hydrodynamic process with a Jingshi section as a research section and a simulation period of 720 hours from 4 months, 1 day 0 to 5 months, 1 day 0 in 2018.
Setting up internal and external boundary conditions of channel
For hydrodynamic simulation models, the water level, flow or water level flow relationship at the boundary position needs to be given. In the invention, the upstream and downstream boundaries all adopt water levels as boundary conditions, wherein the upstream selects a process of water level before the ancient canal check gate, the downstream selects a process of water level before the north-rejection check gate, and the change process of the boundary conditions in a simulation period is shown in figure 3.
In the invention, all the check gates in the research area are in a submerged orifice flow state, so that a flow formula can be written as follows:
Figure BDA0003234317610000121
wherein m represents the comprehensive flow coefficient, e is the opening degree of the brake hole, BgTo limit the total width of sluice water, H is the weir head, ZiFor controlling the water level of the cross-section in front of the gate, ZbIs the elevation of the weir crest. Each within the simulation cycleThe actual regulation process of the check gate is shown in fig. 4.
Third, determining the adaptive relation between the time step and the space step
The space step length under a given time step length is automatically calculated in the model according to the self-adaptive relation between the time step length and the space step length, and the space step length corresponding to the time step length of each section is shown in figure 5.
Fourthly, determining the relation between the space-time step length and the calculation efficiency and the calculation precision
The calculation time step lengths are set to be working conditions of 30s, 60s, 120s.. 7200s and the like, and the relation between the time step lengths and the calculated operation time is obtained by calculating through the hydrodynamic model constructed by the method and is shown in fig. 6. It can be seen from the figure that, after the time step and space step adaptive technique provided by the invention is applied, as the time step is increased, the space step is also increased, so that the grid computing nodes are greatly reduced, and the computing efficiency is obviously increased at the moment. When the time step length continues to increase, the space step length of partial nodes is increased to a certain degree and is overlapped with the building nodes, the space step length is not increased along with the increase of the time step length, the number of the calculation nodes is not reduced, and the calculation speed of the primary model is not obviously increased.
The deviation between the calculated water level and the measured water level at different long time periods obtained by the calculation of the method provided by the invention is shown in table 2. As can be seen from the table, the calculated values of the water level before each gate are compared with the measured values, and the absolute errors are within 10cm, which shows that the simulation precision is within the allowable range by adopting the calculation method of the invention. And with the increase of the time step length and the space step length, the absolute error between the calculated value and the measured value of the water level before each gate is in an ascending trend but within an acceptable range. Therefore, the method provided by the invention can effectively balance the relation between the calculation precision and the calculation efficiency when the water transfer engineering of the open channel is subjected to hydrodynamic real-time calculation, and can improve the calculation efficiency by increasing the calculation time step length on the premise of meeting the requirement of the calculation precision, but when the time step length is increased to a certain degree, the increase of the time step length range influences the calculation precision.
TABLE 1 error table of water level before time step corresponding to gate
Figure BDA0003234317610000131
By adopting the technical scheme disclosed by the invention, the following beneficial effects are obtained:
the invention provides a real-time calculation method of open channel water transfer engineering water power based on a space-time step length self-adaptive technology, which determines the self-adaptive relation between a time step length and a space step length in the real-time calculation process of the open channel water transfer engineering water power, reduces the step length trial and error times caused by result divergence in the calculation, and is more convenient to operate compared with the traditional method for simultaneously giving the time step length and the space step length. The method can obtain the relation between the calculation time step and the calculation efficiency on the basis of the space-time step self-adaptive relation, and effectively improve the efficiency of the hydrodynamic real-time calculation of the open channel water transfer engineering.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that it is obvious to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and the modifications and improvements should be considered within the protection scope of the present invention.

Claims (4)

1. A real-time calculation method for open channel water transfer engineering hydrodynamic force based on a space-time step length self-adaptive technology is characterized by comprising the following steps: comprises the following steps of (a) carrying out,
s1, constructing a hydrodynamic simulation model based on the Saint-Vietnam equation set;
s2, setting internal and external boundary conditions of the channel based on the constructed hydrodynamic simulation model,
s3, setting different time step lengths based on the constructed hydrodynamic simulation model, calculating and obtaining a space step length adaptive to the time step length, and determining a change rule of the space step length along with the time step length;
s4, setting different time steps based on the constructed hydrodynamic simulation model, calculating to obtain calculation operation time corresponding to the different time steps, and determining the change rule of the calculation operation time along with the time steps and the space steps;
the saint-vican equation set includes a continuity equation and a momentum equation,
the equation of continuity is as follows,
Figure FDA0003498163280000011
the momentum equation is as follows,
Figure FDA0003498163280000012
wherein B is the width of the surface of the water passing section; z is water level; t is time; q is the flow; x is the longitudinal distance of the channel along the main flow direction; q is a side inflow; alpha is a momentum correction coefficient; a is the water passing area; g is the acceleration of gravity; sfThe calculation formula for the friction drag ratio is as follows,
Figure FDA0003498163280000013
wherein n iscThe Manning roughness coefficient of the water delivery channel; r is the hydraulic radius;
the inner boundary condition and the outer boundary condition of the channel are respectively an inner boundary condition and an outer boundary condition, the outer boundary condition comprises an upstream boundary condition and a downstream boundary condition, the upstream boundary condition comprises a water level boundary and a flow boundary, and the downstream boundary condition comprises a water level boundary, a flow boundary and a water level-flow relation boundary; the inner boundary condition is a node with obviously changed hydraulic characteristics or geometric shapes in the water delivery system and comprises a check gate and a water diversion port;
aiming at the condition of an inner boundary, a check gate in open channel water transfer engineering belongs to a low-water-head water and soil building, and the flow calculation adopts a calculation method of a wide top weir; because the flow formulas are different under different outflow conditions, the outflow state of the weir gate is firstly determined before the formulas are selected;
the method for discriminating the water flow field of the weir gate is that when hs/H0Submerged discharge at > 0.8, hs/H0When the flow rate is less than or equal to 0.8, the free outflow is realized; when the e/H is more than 0.65, the flow is a weir flow, and the e/H is less than or equal to 0.65, the flow is a hole flow;
wherein H is weir water head, H is Zi-Zb；H0The weir upper total head comprising the near velocity head,
Figure FDA0003498163280000021
v0the current velocity is determined; e is the opening degree of the brake hole; h issWater depth after the gate hs＝Zi+1-Zb；ZbIs the elevation of the weir crest; ziControlling the water level of the cross section in front of the gate; zi+1Controlling the water level of the cross section after the gate;
when the check gate is in a free outflow state, the flow of the passing gate is not influenced by the downstream water level, and the relation between the upstream water level and the downstream water level of the check gate cannot be directly established through a check gate flow formula; therefore, under the condition of free outflow, the throttle gate, the upstream and the downstream are automatically divided into two single channels for processing; aiming at an upstream channel, calculating to obtain the front section water level Z of the check gate by taking a check gate flow formula as a downstream boundary conditioniSum flow rate QiAnd according to the continuous equation, the flow Q of the front section of the gateiFlow Q delivered to rear section of gatei+1Determining an upstream boundary condition of a downstream channel;
the flow rate in the case of free orifice flow is formulated as,
Figure FDA0003498163280000022
the flow equation in the case of free weir flow is expressed as,
Figure FDA0003498163280000023
wherein M is1And M2Respectively representing free bore flow and selfFrom the combined flow coefficient in the case of weir flow, BgIn order to control the total width of the sluice water;
when the check gate is in a submerged outflow state, the relation between the upstream and downstream water levels and the flow of the check gate can be established through a flow formula; in this case, the water delivery system comprising the check gates can be solved as a whole;
the flow equation for the case of submerged orifice flow is expressed as,
Figure FDA0003498163280000024
wherein M is3In order to submerge the comprehensive flow coefficient under the pore flow, the Taylor expansion method is adopted to carry out linearization processing on the formula (6), second-order and above terms are ignored, and the following form can be written,
Figure FDA0003498163280000025
the formula (7) can be rewritten as,
Figure FDA0003498163280000031
in this case, the linearization coefficients of the governing equation of the throttling gate flow formula are respectively,
Ei＝0；
Figure FDA0003498163280000032
Gi＝1；
Figure FDA0003498163280000033
the flow equation for the submerged weir flow case is expressed as,
Figure FDA0003498163280000034
in the formula, M4In order to submerge the comprehensive flow coefficient under the weir flow, the Taylor expansion method is adopted to carry out linearization treatment on the formula (9), the second order and above terms are ignored, and the following form can be written,
Figure FDA0003498163280000035
in this case, the linearization coefficients of the governing equation of the throttling gate flow formula are respectively,
Ei＝0；
Figure FDA0003498163280000036
Gi＝1；
Figure FDA0003498163280000037
2. the open channel water transfer engineering hydrodynamic force real-time calculation method based on the space-time step length adaptive technology as claimed in claim 1, characterized in that: aiming at the outer boundary conditions, assuming that the open channel water transfer project contains Ns sections, the whole water delivery system contains 2Ns unknowns, namely Ns water levels and Ns flow rates, and the solution of the hydrodynamic simulation model also needs 2Ns mutually independent equations; since Ns sections generate Ns-1 buildings in total, i.e., there are 2Ns-2 governing equations, it is necessary to supplement the upstream boundary conditions and the downstream boundary conditions to form a closed system of equations.
3. The open channel water transfer engineering hydrodynamic force real-time calculation method based on the space-time step length adaptive technology according to claim 1, characterized in that: step S3 is specifically to reasonably match the time step Δ t and the space step Δ x to control the phase error generated by numerical dispersion and improve the stability of the hydrodynamic simulation model; get
Figure FDA0003498163280000038
That is, Δ x is automatically divided according to the set Δ t, h0Calculating the initial water depth of the downstream control section of the channel section; setting the length of the whole channel as L, dividing the channel into m sections according to a formula m as L/delta x in the calculation and operation process of the hydrodynamic simulation model, and if m is an integer, keeping delta x unchanged; if m is not an integer, the segment becomes m +1 segment
Δx＝L/(m+1) (12)
According to the relation between the space step length and the time step length, in the actual calculation process, when the set time step length is adjusted, the space step length calculated by the hydrodynamic simulation model is correspondingly changed.
4. The open channel water transfer engineering hydrodynamic force real-time calculation method based on the space-time step length adaptive technology according to claim 3, characterized in that: the step S4 specifically includes the following contents,
s41, determining the relation between the space-time step length and the calculation efficiency; respectively determining the space step length and the calculation operation time under different time step lengths based on a hydrodynamic simulation model, and analyzing the change trends of the space step length and the calculation operation time under different space-time step lengths to obtain the time step length with the highest calculation efficiency;
s42, determining the relation between the calculation time step and the calculation precision; based on a hydrodynamic simulation model, the space step length under different time step lengths and the absolute error between the calculated value of the water level before each check gate and the measured value are respectively determined, and the relation between the calculated time step length and the calculation precision can be obtained.
CN202110997426.9A 2021-08-27 2021-08-27 Open channel water transfer engineering hydrodynamic force real-time calculation method based on space-time step length self-adaptive technology Active CN113779671B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110997426.9A CN113779671B (en) 2021-08-27 2021-08-27 Open channel water transfer engineering hydrodynamic force real-time calculation method based on space-time step length self-adaptive technology

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110997426.9A CN113779671B (en) 2021-08-27 2021-08-27 Open channel water transfer engineering hydrodynamic force real-time calculation method based on space-time step length self-adaptive technology

Publications (2)

Publication Number Publication Date
CN113779671A CN113779671A (en) 2021-12-10
CN113779671B true CN113779671B (en) 2022-03-25

Family

ID=78839702

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110997426.9A Active CN113779671B (en) 2021-08-27 2021-08-27 Open channel water transfer engineering hydrodynamic force real-time calculation method based on space-time step length self-adaptive technology

Country Status (1)

Country Link
CN (1) CN113779671B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115456422B (en) * 2022-09-16 2024-02-02 中国水利水电科学研究院 Dynamic previewing correction method for irrigation area water distribution plan based on computational hydrodynamics
CN115423346B (en) * 2022-09-20 2023-04-07 中国水利水电科学研究院 Real-time measuring and calculating method for flood season adjustable capacity of open channel water transfer project series gate group

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102191758A (en) * 2011-04-02 2011-09-21 中国水利水电科学研究院 Method and system for automatically controlling water level of inverted siphon in open channel

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110647039B (en) * 2019-10-08 2022-03-25 黄河勘测规划设计研究院有限公司 Synchronous control self-adaptive balance scheduling method for long-distance open channel water delivery project

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102191758A (en) * 2011-04-02 2011-09-21 中国水利水电科学研究院 Method and system for automatically controlling water level of inverted siphon in open channel

Also Published As

Publication number Publication date
CN113779671A (en) 2021-12-10

Similar Documents

Publication Publication Date Title
WO2021129039A1 (en) Method and system for calculating cross-reservoir drainage basin river runoff
CN113779671B (en) Open channel water transfer engineering hydrodynamic force real-time calculation method based on space-time step length self-adaptive technology
CN110543731B (en) Water-sand separate scheduling simulation method and system for high-sand-content river reservoir
CN104265652B (en) Collaborative optimization design method for large-flow low-lift pump station
CN107045568B (en) River course roughness inversion method based on dynamic programming successive approximation method
CN105201916A (en) Designing method for hydraulic power of space guide-blade centrifugal pump
CN111046574B (en) Flood control and drainage calculation method for lake and river gate pump system in plain lake region
CN105574288B (en) Method for designing water inlet conduit three-dimensional body flow surface of high-performance large-flow pump station
CN110210109B (en) Numerical simulation method and system for reverse water flow of weir gate engineering in river network
CN106528994B (en) A kind of pressure regulation chamber venting hole wind speed simulation method coupled based on gas-liquid interface
CN109271672A (en) A kind of river-lake-pumping plant influences each other the river water surface curve calculation method under acting on
CN106407530A (en) Synchronous combined calculation method for sediment scour and deposition of cascade reservoir
CN106874595A (en) Water transfer pipe network computational methods based on node parameter technology
CN108532532A (en) The moisture-proof water front formulating method of tidal waterway flood control
CN106446438B (en) A kind of nearly far field approach of coupled numerical simulation of power plant's warm water discharge deep water discharge
WO2015033269A1 (en) A control system for operation of irrigation canals
CN115423346A (en) Real-time measuring and calculating method for flood season adjustable capacity of open channel water transfer project series gate group
Xu et al. Flow pattern and anti-silt measures of straight-edge forebay in large pump stations.
CN115034113A (en) Fishway rest pool structure determination method and system
CN101178051B (en) Cave system differential surge chamber
CN102890732B (en) Hydrodynamic condition parallel numerical simulation method for channel with various structures
CN115809528A (en) Construction method of water hammer calculation model of long-distance gravity flow pipeline
CN204185835U (en) Power station free pressure flow tail water discharge
CN115564238B (en) Small reservoir flood forecasting and flood regulating analysis method based on hydrodynamic mechanism
CN109371897A (en) A kind of fish pass import moisturizing energy dissipating model test apparatus and test method

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant