CN112668256A - Vertical seam type fishway vortex identification method - Google Patents
Vertical seam type fishway vortex identification method Download PDFInfo
- Publication number
- CN112668256A CN112668256A CN202110047249.8A CN202110047249A CN112668256A CN 112668256 A CN112668256 A CN 112668256A CN 202110047249 A CN202110047249 A CN 202110047249A CN 112668256 A CN112668256 A CN 112668256A
- Authority
- CN
- China
- Prior art keywords
- vortex
- calculation
- equation
- flow
- fishway
- 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.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 72
- 238000004364 calculation method Methods 0.000 claims abstract description 54
- 239000012530 fluid Substances 0.000 claims abstract description 36
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 27
- 239000012071 phase Substances 0.000 claims description 14
- 238000012805 post-processing Methods 0.000 claims description 6
- 230000008569 process Effects 0.000 claims description 6
- 238000004458 analytical method Methods 0.000 claims description 5
- 238000011161 development Methods 0.000 claims description 5
- 238000010586 diagram Methods 0.000 claims description 4
- 238000013213 extrapolation Methods 0.000 claims description 4
- 230000021715 photosynthesis, light harvesting Effects 0.000 claims description 4
- 230000001133 acceleration Effects 0.000 claims description 3
- 239000008346 aqueous phase Substances 0.000 claims description 3
- 230000008878 coupling Effects 0.000 claims description 3
- 238000010168 coupling process Methods 0.000 claims description 3
- 238000005859 coupling reaction Methods 0.000 claims description 3
- 239000006185 dispersion Substances 0.000 claims description 3
- 230000005484 gravity Effects 0.000 claims description 3
- 239000007791 liquid phase Substances 0.000 claims description 3
- 239000011159 matrix material Substances 0.000 claims description 3
- 238000005192 partition Methods 0.000 claims description 3
- 230000000704 physical effect Effects 0.000 claims description 3
- 238000012545 processing Methods 0.000 claims description 3
- 238000012360 testing method Methods 0.000 claims description 3
- 230000009466 transformation Effects 0.000 claims description 3
- 238000005516 engineering process Methods 0.000 abstract description 4
- 238000001514 detection method Methods 0.000 abstract description 3
- 241000251468 Actinopterygii Species 0.000 description 8
- 238000004088 simulation Methods 0.000 description 7
- 238000013461 design Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 230000006378 damage Effects 0.000 description 2
- 206010024453 Ligament sprain Diseases 0.000 description 1
- 208000010040 Sprains and Strains Diseases 0.000 description 1
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 230000004308 accommodation Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
- 238000012800 visualization Methods 0.000 description 1
Images
Landscapes
- Management, Administration, Business Operations System, And Electronic Commerce (AREA)
Abstract
The invention relates to a vertical seam type fishway vortex identification method, and belongs to the field of hydraulic engineering, ecological engineering and engineering fluid detection and control. The method comprises the following steps: the method specifically comprises the following steps: and identifying the vortex in the vertical seam type fishway by adopting a second invariant Q in the velocity gradient tensor in the Q criterion with Galileo invariance. The method comprises the following steps: firstly, establishing a computational fluid mechanics model based on a Q criterion; secondly, carrying out numerical calculation on the three-dimensional flow field; and finally, performing vortex identification by adopting a Q criterion. The method effectively identifies the vortex area in the vertical seam type fishway, has high effectiveness, and simultaneously expands the application of the vortex identification technology in the field of hydraulic engineering.
Description
Technical Field
The invention relates to a vertical seam type fishway vortex identification method, in particular to a vertical seam type fishway vortex identification method, which is a fishway vortex identification method combining model establishment and vortex dynamics identification methods and belongs to the field of hydraulic engineering, ecological engineering and engineering fluid detection and control.
Background
Hydraulic engineering also brings some influences on ecological environment while making interest and removing harm, for example, the ecological environment causes obstacles to fish migration. The fishway is used as an ecological compensation project and plays an important role in protecting fish resources and recovering river biodiversity. In numerous fishway types, the actual operation of the vertical seam type fishway has achieved good effect, however, the energy dissipation of the vertical seam type fishway is mainly concentrated at the vertical seam, the narrow beam of the vertical seam enables water flow to form vortex, the flow rate in the fishway is too high, the flow state of the water flow is relatively disordered due to the large vortex range, and the fishes with small volume are easily restricted by upward tracking. Vortex flow states such as appearing in rivers can cause the injury of different degrees to fish, if sprain the health, hit bad eyes, balancing ability decline, if the indoor vortex yardstick of pond is too big, surpasss the accommodation of fish, fish will lose the direction, even bump baffle and boundary wall, influence fish efficiency. With the development of modern fluid mechanics science, the identification and visualization research on the vortex is also deepened continuously, the vortex structure is widely appeared and applied to fluid machinery, and meanwhile, the vortex structure has many breakthroughs in the fields of medicine, aviation and oceans. Therefore, the hydraulic characteristics of the vertical seam type fishway, particularly the vortex characteristics in the fishway, are researched, and a basis is provided for optimizing the fishway design and repairing the fish habitat.
In view of the wide application of the vortex identification technology in the fluid field, the vortex identification technology can be used for identifying the vortex in the fishway and has important guiding significance for fishway design, and the related vortex criteria under the Galileo invariance for identifying the vortex mainly comprise the following representative methods.
λ2Criterion is as follows: lambda [ alpha ]2The criterion omits a transient stress item and a viscosity item, and passes through S2+Q2To obtain a very small pressure at the vortex core, which inevitably causes corresponding errors. From λ2The local minimum pressure point defined by the criterion needs to satisfy that the pressure gradient near the point is zero, and S2+Q2There are two negative eigenvalues. Thus, λ2The criterion discards vortex structures at points where the pressure is minimal but not zero gradient. Lambda [ alpha ]2The vortexes identified by the criterion are mixed with small-scale vortexes, so that lambda is easily received2The influence of the threshold;
λcicriterion is as follows:
eliminating large regions of helical motion, including
Strong inward eddy current sum
Stronger outward vortex. In addition, the criterion of the vortex intensity is easily influenced by the local vortex intensity. Strictly speaking, the vortex region will be expanded with a greater local vortex intensity.
The criterion of delta is as follows: this criterion is also a weak criterion. Because this criterion, while indicating that a region V with a vortex has a complex (imaginary) eigenvalue, does not make it clear whether all eigenvalues of V are real for a region without a vortex.
The summary of the research on the above methods shows that in the above mentioned typical methods with galileo invariance, there are some disadvantages in identifying fluid vortexes, and the identification effect is general, so it is necessary to establish a numerical simulation method capable of effectively identifying vortexes in the vertical seam type fishway.
Disclosure of Invention
The invention provides a method for effectively identifying vertical seam type fishway vortexes, which plays an important role in optimizing fishway design and expands the application of a vortex identification technology in the field of fluid.
The technical scheme adopted by the invention for solving the technical problems is as follows: a vertical seam type fishway vortex identification method comprises the following steps:
1) establishing a three-dimensional geometric model of a vertical seam type fishway calculation domain, and establishing the three-dimensional geometric model of the calculation domain by using geometric modeling software according to a structure size diagram of a three-dimensional flow calculation domain which is actually researched;
2) establishing a three-dimensional flow computational fluid mechanics model, wherein the three-dimensional flow computational fluid mechanics model comprises a flow control equation;
the fluid flowing through the fishway is assumed to be incompressible Newtonian fluid, and the flow control equation is composed of a continuous equation, a momentum equation and a k-epsilon equation:
the continuous equation:
the momentum equation:
wherein t represents time; u. ofi、ujAre respectively xiAnd xjAverage flow velocity in the direction (i, j ═ 1,2, 3); p is the average pressure; ρ is the fluid density; giThe gravity acceleration in different directions; k is turbulent kinetic energy; epsilon is the turbulent kinetic energy dissipation rate; mu is the water molecule viscosity coefficient; v. ofTIs the turbulent flow motion viscosity coefficient; cμ0.085, which is a semi-empirical coefficient;
the k equation and the epsilon equation have the following forms
In the above formulas, σkAnd σεThe turbulence Prandtl constants of the k equation and the epsilon equation, respectively, are taken at this timek＝σε＝0.72；Cε1For a semi-empirical coefficient, take Cε1＝1.42；Cε2Calculated from the shear rates of the k, ε and RNG models, take Cε2＝1.68；PkFor turbulent energy generation by mean velocity gradientAn item;
the principle of tracking the water flow free surface motion by adopting a volume resolution method VOF is that the difference of the same fluid control equation form but different physical properties of air and water is substituted into a control equation in a proportion mode, and then the position of a free surface is determined by solving a volume fraction continuous equation of water and gas phases. The equation is in the form:
in the formula: alpha is alphawIs the volume fraction of water; alpha is alphaw0 means that all gas phases are in the calculation unit; alpha is alphaw1 indicates that all water phases are in the calculation unit; alpha is more than 0w< 1 indicates that both the aqueous phase and the gas phase are contained in the calculation unit.
3) Calculating domain grid division, namely performing grid division on a calculation region by adopting a hexahedral structured grid, encrypting grids of a fishway side wall, a top region and a water flow region at a vertical seam so as to facilitate numerical calculation, obtaining refined flowing physical parameters, estimating calculation grid dispersion errors by adopting grid uncertainty estimation methods such as GCI and GCI-OR based on Richardson extrapolation, and determining the number of calculation grids;
4) setting boundary conditions and algorithms, and setting corresponding calculation areas, solving methods and boundary conditions according to the actual operation conditions of the researched object to carry out numerical calculation of the three-dimensional flow field: selecting a pool room to be simulated in the calculation area; adopting a volume control method to disperse partial differential equation sets, and adopting a SIMPLE method for pressure and speed coupling; the model inlet adopts a speed inlet, and the average flow speed of the early test data is taken as the inlet flow speed; the outlet is a pressure outlet; the top is provided with a gas pressure inlet with the pressure of 1.01 multiplied by 105 Pa; the side wall, the bottom and the partition board are set as fixed wall boundaries which adopt standard non-slip boundaries, namely the wall surface speed is 0 m/s; and based on the established computational fluid dynamics model, performing numerical calculation on the three-dimensional flow field;
5) and (4) post-processing analysis, namely analyzing and processing the result calculated and output in the step 4) by adopting post-processing software to obtain flow field information, wherein the flow field information comprises a velocity field, a pressure difference, a vorticity field, gas-phase and liquid-phase volume fractions, a vortex form and an evolution development process thereof.
6) Identifying the vertical seam type fishway vortex based on the Q criterion, and writing an application program of the Q criterion in the discrete vector field data to identify the vortex.
Performing vortex identification on a vortex region in a three-dimensional flow field of a region to be distinguished by adopting a Q criterion theoretical method, wherein the Q value is as follows:
wherein S and Ω are the symmetric and antisymmetric portions of the velocity gradient tensor matrix, respectively, which can be solved by the following equations:
the velocity gradient in the above equation is obtained based on the coordinate transformation of the velocity gradient tensor V under the original coordinate system:
wherein
Namely, it is
Based on the velocity gradient tensor according to a preset identification method
The second invariant Q in (1) identifies the vortex region in the slot fishway, when Q is>0, then the presence of a vortex is demonstrated, otherwise none.
Specifically, in the mesh division in 3), a hexahedral structure mesh with good convergence is adopted to perform mesh division on a calculation area, and the time step length depends on the size of the mesh and the flow velocity;
specifically, in the grid encryption processing in 3), the simulation precision of the water flow area at the side wall, the top area and the vertical seam of the fishway directly influences the simulation result of the water flow structure of the pool chamber, and then the grid is encrypted;
specifically, the 5) post-processing software can be analyzed by using the CFD software with its own post-processing and general CFD post-processing software, such as Tecplot, Paraview, and the like.
Specifically, according to the criterion Q in 6), Q >0 indicates that the rotation tensor Ω is greater than the strain rate tensor S, that is, the rotation force of the fluid is greater than the strain force, so as to ensure the existence of the vortex, and effectively identify the vortex region in which the rotation of the fluid in the flow field is dominant.
The invention has the beneficial effects that:
by means of a pair of2Criterion, lambdaciThe comparison of the criterion, the delta criterion and the Q criterion shows that: the Q method gives the best results. Criterion Q: q>0 means that the rotational force of the fluid is greater than the strain force (i.e., the vortex tensor is greater than the strain rate tensor), thereby ensuring the presence of vortices. The larger the Q value is, the larger the difference between the vorticity and the deformation rate is; generation of vortices, Q>The 0 criterion is more stringent than the vorticity criterion. The number of flow structures identified by the Q criterion represents the number of vortex structures in the flow field and can capture a large amount of flow information, such as: the extent of distribution, volume, shape, profile, etc. of the vortices. Therefore, the method for identifying the vertical seam type fishway vortex by adopting the Q criterion is the best choice considering the advantages of all main criteria.
The invention relates to a method for identifying a vertical seam type fishway vortex, which adopts a method for carrying out geometric modeling and numerical simulation calculation of a flow field on a three-dimensional flow field in a fishway to ensure the accuracy of vortex identification, adopts a vortex identification method that a second Galileo invariant Q & gt 0 of a velocity gradient tensor represents a vortex structure, the physical significance of the method lies in that the vortex structure not only requires the existence of vorticity (antisymmetric tensor omega), but also requires the antisymmetric tensor omega to overcome the offset effect represented by the symmetric tensor S, thereby improving the accuracy of fishway vortex identification, and is helpful for researching the vortex generation process of the vortex area in the fishway by analyzing the physical information of the convection field, the method has important practical significance and ecological engineering value for recognizing the vortex structure characteristics in the fishway and solving a plurality of problems caused by the vortex, and can be popularized and applied to the field of fluid detection and control by using various vortex recognition methods.
Drawings
FIG. 1 is a flow chart of the calculation of vortex identification for a slotted fishway using the Q criterion.
Detailed Description
The invention is further described below with reference to the accompanying drawings and specific embodiments.
Example 1: referring to fig. 1, a method for identifying a vertical seam type fishway vortex, the method comprising the steps of:
1) establishing a three-dimensional geometric model of a vertical seam type fishway calculation domain: according to a structure size diagram of a three-dimensional flow calculation domain which is actually researched, a three-dimensional geometric model of the calculation domain is established by utilizing geometric modeling software;
2) a three-dimensional flow computational fluid dynamics model is established, the three-dimensional flow computational fluid dynamics model including a flow control equation.
The fluid flowing through the fishway is assumed to be incompressible Newtonian fluid, and the flow control equation is composed of a continuous equation, a momentum equation and a k-epsilon equation:
the continuous equation:
the momentum equation:
wherein t represents time; u. ofi、ujAre respectively xiAnd xjAverage flow velocity in the direction (i, j ═ 1,2, 3); p is the average pressure; ρ is the fluid density; giThe gravity acceleration in different directions; k is turbulent kinetic energy; epsilon is the turbulent kinetic energy dissipation rate; mu is the water molecule viscosity coefficient; v. ofTIs the turbulent flow motion viscosity coefficient; cμ0.085, a semi-empirical coefficient.
The k equation and the epsilon equation have the following form:
in the above formulas, the other sigmakAnd σεThe turbulence Prandtl constants of the k equation and the epsilon equation, respectively, are taken at this timek＝σε＝0.72；Cε1For a semi-empirical coefficient, take Cε1＝1.42；Cε2Calculated from the shear rates of the k, ε and RNG models, take Cε2＝1.68；PkGenerating terms for the turbulence energy caused by the average velocity gradient;
the principle of tracking the water flow free surface motion by adopting a volume resolution method VOF is that the difference of the same fluid control equation form but different physical properties of air and water is substituted into a control equation in a proportion mode, and then the position of a free surface is determined by solving a volume fraction continuous equation of water and gas phases. The equation is in the form:
in the formula: alpha is alphawIs the volume fraction of water; alpha is alphaw0 means that all gas phases are in the calculation unit; alpha is alphaw1 indicates that all water phases are in the calculation unit; alpha is more than 0w< 1 indicates that both the aqueous phase and the gas phase are contained in the calculation unit;
3) calculating domain grid division, namely performing grid division on a calculation region by adopting a hexahedral structured grid, encrypting grids of a fishway side wall, a top region and a water flow region at a vertical seam so as to facilitate numerical calculation to obtain refined physical parameters, and estimating calculation grid dispersion errors and determining the number of calculation grids by adopting grid uncertainty estimation methods such as GCI, GCI-OR and the like based on Richardson extrapolation;
4) setting boundary conditions and algorithms, and setting corresponding calculation areas, solving methods and boundary conditions according to the actual operation conditions of the researched object to carry out numerical calculation of the three-dimensional flow field: selecting a pool room to be simulated in the calculation area; adopting a volume control method to disperse partial differential equation sets, and adopting a SIMPLE method for pressure and speed coupling; the model inlet adopts a speed inlet, and the average flow speed of the early test data is taken as the inlet flow speed; the outlet is a pressure outlet; the top is provided with a gas pressure inlet with the pressure of 1.01 multiplied by 105 Pa; the side wall, the bottom and the partition board are set as fixed wall boundaries which adopt standard non-slip boundaries, namely the wall surface speed is 0 m/s; and performing numerical calculation on the three-dimensional flow field based on the established computational fluid dynamics model.
5) Post-processing analysis, adopting post-processing software to analyze and process the result output by the calculation of 4), and obtaining flow field information: including velocity fields, pressure differences, vorticity fields, gas and liquid phase volume fractions, vortex morphology and evolution development processes thereof.
6) Identifying the vertical seam type fishway vortex based on the Q criterion, and writing an application program of the Q criterion in the discrete vector field data to identify the vortex.
Performing vortex identification on a vortex region in a three-dimensional flow field of a region to be distinguished by adopting a Q criterion theoretical method, wherein the Q value is as follows:
wherein S and Ω are the symmetric and antisymmetric portions of the velocity gradient tensor matrix, respectively, which can be solved by the following equations:
the velocity gradient in the above equation is obtained based on the coordinate transformation of the velocity gradient tensor V under the original coordinate system:
wherein
Namely, it is
According to a preset identification method, identifying a vortex area in the perps fishway based on a second invariant Q in the velocity gradient tensor, and when Q is greater than 0, proving that a vortex exists, otherwise, not.
Further, in the mesh division in 3), the calculation area is subjected to mesh division by adopting a hexahedral structure mesh with better convergence, and the time step length depends on the size of the mesh and the flow velocity;
further, the grid in 3) is encrypted, and the simulation result of the pool chamber water flow structure is directly influenced by the simulation precision of the side wall, the top area and the water flow area at the vertical seam of the fishway, so that the grid is encrypted;
further, the post-processing software of 5) can utilize the post-processing of each CFD software and the general CFD post-processing software to perform analysis, such as Tecplot, Paraview, and the like.
Further, according to the criterion Q in 6), Q >0 indicates that the rotation tensor Ω is greater than the strain rate tensor S, that is, the rotation force of the fluid is greater than the strain force, so as to ensure the existence of the vortex, and effectively identify the vortex region in which the rotation of the fluid in the flow field is dominant.
The technical scheme of the invention is explained in detail by combining the attached drawings, the invention combines a three-dimensional flow field, establishes a model, performs numerical simulation analysis, and constructs a method for identifying a vortex region in the vertical seam type fishway by using a second invariant Q in a velocity gradient tensor, when Q is greater than 0, the vertical seam type fishway is proved to have vortex, a large amount of flow information can be captured from the vortex flow characteristics, the vortex generation process of the vortex region in the fishway can be reflected, and the vertical seam type fishway is favorably and continuously optimized and improved in research so as to meet the development requirement of the current ecological engineering.
The present invention is not limited to the technical method described, and those skilled in the art can make various substitutions and modifications within the principle and technical idea of the present invention, and the scope of the present invention should be considered as the protection scope of the present invention.
Claims (6)
1. A vertical seam type fishway vortex identification method is characterized by comprising the following steps: the method specifically comprises the following steps:
1) establishing a three-dimensional geometric model of a vertical seam type fishway calculation domain: according to a structure size diagram of a three-dimensional flow calculation domain which is actually researched, a three-dimensional geometric model of the calculation domain is established by utilizing geometric modeling software;
2) establishing a three-dimensional flow computational fluid mechanics model, wherein the three-dimensional flow computational fluid mechanics model comprises a flow control equation;
the fluid flowing through the fishway is assumed to be incompressible Newtonian fluid, and the flow control equation is composed of a continuous equation, a momentum equation and a k-epsilon equation:
the continuous equation:
the momentum equation:
wherein t represents time; u. ofi、ujAre respectively xiAnd xjAverage flow velocity in the direction (i, j ═ 1,2, 3); p is the average pressure; ρ is the fluid density; giThe gravity acceleration in different directions; k is turbulent kinetic energy; epsilon is the turbulent kinetic energy dissipation rate; mu is the water molecule viscosity coefficient; v. ofTIs the turbulent flow motion viscosity coefficient; cμ0.085, which is a semi-empirical coefficient;
the k equation and the epsilon equation have the following form:
in the above formulas, σkAnd σεRespectively k equation and epsilon squareThe turbulent Prandtl constant of the equation, where σ is takenk＝σε＝0.72；Cε1For a semi-empirical coefficient, take Cε1＝1.42；Cε2Calculated from the shear rates of the k, ε and RNG models, take Cε2＝1.68；PkGenerating terms for the turbulence energy caused by the average velocity gradient;
the method adopts a volume resolution method VOF to track the movement of the free surface of water flow, and adopts the principle that the difference of the same fluid control equation form but different physical properties of air and water is substituted into a control equation in a proportion mode, so that the position of the free surface is determined by solving a volume fraction continuous equation of water and gas phases, wherein the equation form is as follows:
in the formula: alpha is alphawIs the volume fraction of water; alpha is alphaw0 means that all gas phases are in the calculation unit; alpha is alphaw1 indicates that all water phases are in the calculation unit; alpha is more than 0w< 1 indicates that both the aqueous phase and the gas phase are contained in the calculation unit;
3) calculating domain gridding, namely gridding a calculation region by adopting hexahedral structured grids, encrypting the grids of the side wall, the top region and the water flow region at the vertical seam of the fishway so as to facilitate numerical calculation, obtaining refined flowing physical parameters, estimating the calculation grid dispersion error by adopting a grid uncertainty estimation method based on the Richardson extrapolation method and determining the number of the calculation grids;
4) setting boundary conditions and algorithms, and setting corresponding calculation areas, solving methods and boundary conditions according to the actual operation conditions of the researched object to carry out numerical calculation of the three-dimensional flow field: selecting a pool room to be simulated in the calculation area; adopting a volume control method to disperse partial differential equation sets, and adopting a SIMPLE method for pressure and speed coupling; the model inlet adopts a speed inlet, and the average flow speed of the early test data is taken as the inlet flow speed; the outlet is a pressure outlet; the top is provided with a gas pressure inlet with the pressure of 1.01 multiplied by 105Pa; a side wall,The bottom and the partition board are set as fixed wall boundaries which adopt standard non-slip boundaries, namely the wall surface speed is 0 m/s; and based on the established computational fluid dynamics model, performing numerical calculation on the three-dimensional flow field;
5) post-processing analysis, namely analyzing and processing the result output by the calculation in the step 4) by adopting post-processing software to obtain flow field information;
6) identifying the vertical seam type fishway vortex based on the Q criterion, and writing an application program of the Q criterion in the discrete vector field data to identify the vortex;
performing vortex identification on a vortex region in a three-dimensional flow field of a region to be distinguished by adopting a Q criterion theoretical method, wherein the Q value is as follows:
wherein S and Ω are the symmetric and antisymmetric portions of the velocity gradient tensor matrix, respectively, which can be solved by the following equations:
the velocity gradient in the above equation is based on the velocity gradient tensor in the original coordinate system
Obtaining the following coordinate transformation:
wherein
Namely:
according to a preset identification method, identifying a vortex region in the perps fishway based on a second invariant Q in the velocity gradient tensor V, and when Q is greater than 0, the rotation tensor omega is greater than the strain rate tensor S, namely the rotation force of the fluid is greater than the strain force, the fact that a vortex exists is proved, and otherwise, the vortex does not exist.
2. The method of claim 1, wherein the method comprises the following steps: in the structural size diagram of the three-dimensional flow calculation domain in the step 1), different calculation domains can establish a three-dimensional geometric model of the corresponding calculation domain according to the sizes of the calculation domains.
3. The method of claim 1, wherein the method comprises the following steps: and 3) carrying out meshing on the calculation area by adopting a hexahedral structure mesh with better convergence, wherein the time step length depends on the size of the mesh and the flow velocity.
4. The method of claim 1, wherein the method comprises the following steps: the grid uncertainty estimation method based on the Richardson extrapolation method in the step 3) comprises GCI, GCI-OR, GCI-LN, GCI-R, CF and FS.
5. The method of claim 1, wherein the method comprises the following steps: the post-processing software in the step 5) can be analyzed by utilizing the post-processing of each CFD software and the general CFD post-processing software.
6. The method of claim 1, wherein the method comprises the following steps: and 5) flow field information including a velocity field, a pressure difference, a vorticity field, gas-phase and liquid-phase volume fractions, a vortex form and an evolution development process thereof.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110047249.8A CN112668256B (en) | 2021-01-14 | 2021-01-14 | Vertical seam type fishway vortex recognition method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110047249.8A CN112668256B (en) | 2021-01-14 | 2021-01-14 | Vertical seam type fishway vortex recognition method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112668256A true CN112668256A (en) | 2021-04-16 |
| CN112668256B CN112668256B (en) | 2024-01-23 |
Family
ID=75415086
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110047249.8A Active CN112668256B (en) | 2021-01-14 | 2021-01-14 | Vertical seam type fishway vortex recognition method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112668256B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116069743A (en) * | 2023-03-06 | 2023-05-05 | 齐鲁工业大学(山东省科学院) | Fluid data compression method based on time sequence characteristics |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109977345A (en) * | 2019-01-29 | 2019-07-05 | 河海大学 | A kind of method for numerical simulation of axial-flow pump clearance leakage of blade tip vortex cavitation |
| CN110727996A (en) * | 2019-09-17 | 2020-01-24 | 北京理工大学 | Turbulence model correction method suitable for dynamic boundary streaming |
-
2021
- 2021-01-14 CN CN202110047249.8A patent/CN112668256B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109977345A (en) * | 2019-01-29 | 2019-07-05 | 河海大学 | A kind of method for numerical simulation of axial-flow pump clearance leakage of blade tip vortex cavitation |
| CN110727996A (en) * | 2019-09-17 | 2020-01-24 | 北京理工大学 | Turbulence model correction method suitable for dynamic boundary streaming |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116069743A (en) * | 2023-03-06 | 2023-05-05 | 齐鲁工业大学(山东省科学院) | Fluid data compression method based on time sequence characteristics |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112668256B (en) | 2024-01-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Liu et al. | An ISPH simulation of coupled structure interaction with free surface flows | |
| Buchner et al. | Dynamic stall in vertical axis wind turbines: comparing experiments and computations | |
| Sun et al. | Detection of Lagrangian coherent structures in the SPH framework | |
| Lubin et al. | Large eddy simulation of turbulence generated by a weak breaking tidal bore | |
| Lee et al. | Fluid–structure interaction analysis on a flexible plate normal to a free stream at low Reynolds numbers | |
| Li et al. | Research on dam-break flow induced front wave impacting a vertical wall based on the CLSVOF and level set methods | |
| Bakhtyar et al. | Numerical simulation of surf–swash zone motions and turbulent flow | |
| Choi et al. | A laboratory experiment of rip currents between the ends of breaking wave crests | |
| Li et al. | Research on dam-break induced tsunami bore acting on the triangular breakwater based on high order 3D CLSVOF-THINC/WLIC-IBM approaching | |
| Malik et al. | Shear improved Smagorinsky model for large eddy simulation of flow in a stirred tank with a Rushton disk turbine | |
| Kumar et al. | Central upwind scheme based immersed boundary method for compressible flows around complex geometries | |
| Coppel et al. | Simulating the fluid dynamic behaviour of oar blades in competition rowing | |
| CN112668256A (en) | Vertical seam type fishway vortex identification method | |
| Zhao et al. | Numerical study of a turbulent hydraulic jump | |
| KR101106548B1 (en) | Method for analyzing shallow water flow using the two-dimensional river flow model with tensor-type eddy viscosity | |
| Pham et al. | Quantitative comparison between volume-of-fluid and two-fluid models for two-phase flow simulation using OpenFOAM | |
| Liang et al. | Numerical study of the Reynolds-number dependence of two-dimensional scour beneath offshore pipelines in steady currents | |
| Yoshikawa et al. | LES for wind load estimation by unstructured grid system | |
| Paik et al. | Analysis of unstable vortical structure in a propeller wake affected by a simulated hull wake | |
| Biausser et al. | Numerical simulations of three-dimensional wave breaking by coupling of a VOF method anda boundary element method | |
| Yushkov et al. | Computational investigation of turbulent flow impact on non-cohesive soil erosion near foundations of gravity type oil platforms | |
| Akrami et al. | A sharp MLS penalty immersed finite element method for fluid-structure interaction of highly deformable slender body in turbulent flow | |
| JiSeok et al. | Flow around a flexible plate in a free stream | |
| Zhao et al. | Numerical investigation of the vortex induced motion of SPAR in uniform current | |
| O’Reilly et al. | A Lattice-Boltzmann-based perturbation 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 |