CN110008509B - Method for analyzing internal solitary wave action force characteristics under consideration of background flow field - Google Patents
Method for analyzing internal solitary wave action force characteristics under consideration of background flow field Download PDFInfo
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Abstract
The invention provides an analysis method for internal solitary wave action force characteristics under the consideration of a background flow field, which comprises the following steps: step 1: performing numerical simulation on the south-sea circulation by using a three-dimensional ocean numerical model; step 2: establishing an internal wave numerical value water tank; and step 3: the effect of internal waves on the marine structure is determined by considering the internal wave numerical water tank and the marine structure network model of the background process. The invention solves the problem that the background flow field can not be considered by the internal wave-making method, and combines the internal wave ocean mode, the internal wave computational fluid mechanics method and the internal wave acting force theoretical method for the first time to form a complete computing system of the internal wave-making method and the force measuring method which consider the background flow field. The method can enable the research on the effect of the internal wave on the structure to be closer to the actual situation, and can play a guiding role in the calculation of the safety load and the structural design of the offshore structure.
Description
Technical Field
The invention relates to the technical field of image processing, in particular to an analysis method for internal solitary wave action force characteristics under the consideration of a background flow field.
Background
With the continuous development of offshore drilling and the continuous exploitation of offshore oil fields, people are looking to move to deep sea. The south China sea area has rich oil and gas reserves, and becomes a strategic resource base for the production and development of the marine petroleum and natural gas in China. However, the south sea also has a complex phenomenon of stratification of seawater, and the activity of internal waves is very frequent.
Ocean internal waves have great influence and threat on marine transportation and offshore engineering construction (including ocean platforms, ocean riser systems, submarine pipeline systems, mooring and mooring lines, oil storage vessels, and the like). In 1963, day 4 and 10, the nuclear submarine "long tail shark" in the United states was lost, and 129 people were all in distress, because the large-amplitude internal solitary wave pulled vertically deep into the ocean in a short time. In the 70 s of the nineteenth century, data report that after 4 months of monitoring, the oil drilling machine in the anderman sea was twisted 90 degrees after the soliton internal wave passed through and pushed beyond thirty or more meters; in 1990, during the early extended testing of flowered oil fields, accidents caused by sudden strong currents generated by internal solitary waves to cause cable breakage, hull collision, and even breakage and crushing of floating hoses have occurred (cheng Jing Zi, 1996). In 14 days 7 and 1990, during the early extension test period of the south-sea Lufeng oil field, the sudden strong current generated by the internal solitary wave makes the connection between the number VI of the semi-submersible drilling ship and the anchored oil tanker 'AyerBiru' difficult; then, on day 8, 12, and in less than 5 minutes, the intense current again caused the tanker to swing through an angle of 110 degrees. Many facts show that the internal waves become important factors for restricting the exploration and exploitation of marine oil and gas and the safety of submarine navigation, and the harm of the internal waves must be considered in the design and installation of marine engineering structures in the south China sea area.
The internal solitary wave is one of the most frequent internal wave phenomena in south sea. The luignong strait is used as the main channel connecting the pacific ocean and the south ocean, and when the solar tide is transmitted from the pacific ocean to the north of the south ocean, the maximum flow velocity of the tide exceeds 1m/s because the water depth at the luignon strait is shallow. When such strong astronomical tides flow through the various terrains of the lusong channel, severe barocline signals are generated, which are the largest sources of endogenous tides in the edge sea of the world (Jan et al, 2008). The internal tide generates an internal solitary wave through nonlinear fission in the propagation process, passes through a deep basin in the south sea, is transmitted into a land frame slope area and is finally broken in the offshore area. Their maximum horizontal flow rate exceeds 2m/s (Zhao et al, 2012) and maximum amplitude exceeds 150m (Klymak et al, 2006).
The application of the remote sensing observation means can directly acquire the global information of the plane distribution of the sea surface internal wave characteristic physical quantity and can capture an internal isolated wave group. Hsu et al (2000) showed distribution of internal waves in the north of the south sea using hundreds of ERS-1/2SAR images from 1993 to 2000. The results show that the main distribution regions of internal waves are the lusong channel, the vicinity of the east sand synusia and the east-sea region of the hainan island. Zheng et al (2007) use SAR data from 1995 to 2001 to count the occurrence frequency of isolated waves in north of the south sea, and find that there are internal isolated waves in the north of the south sea all the year round, but there are significant seasonal changes, the occurrence frequency of the isolated waves in summer is the most, and the occurrence frequency in winter is the least.
In the case of a two-layer fluid with a flat bottom and limited depth, the internal solitary wave keeps its waveform unchanged during its propagation, which is called stationary internal solitary wave, and can be described by using KdV (Korteweg-de Vries), ekdv (extended kdv), MCC (Miyata-Choi-Camassa) and other theories (Helfrich and Melville, 2006). KdV theory is based on the condition of weak nonlinearity, weak dispersion and balance of the two. In the middle and low latitude sea area, the effect of the conversion effect is shown, and a rotation term is introduced to obtain rKdv (rotated-modified Kdv). The presence of the rotation term enhances the dispersion effect, enlarging the distance between the solitary wave trains and reducing the number of solitons in the trains (Holloway et al, 1999). Considering both the higher order nonlinearity and the transmutation effect, a read-modified extended Kdv is constructed.
Experimental studies have shown that KdV theory is consistent with experimental results at small amplitudes, but KdV theory is clearly inconsistent with experimental results at large amplitudes. This is because the influence of the higher order nonlinear terms increases gradually with increasing amplitude of the internal solitary wave, and the nonlinear terms are no longer in balance with the dispersion (Walker et al, 2003). In addition, the early KdV equation and improvements mostly used two-layer ocean models. The observation and research show that the simulation effect of the two-layer ocean model has larger deviation with the observation result in the actual ocean, such as smaller simulated nonlinear speed c, smaller amplitude of the inner solitary wave, smaller half-wave width delta and the like. To solve these problems, one starts to use a continuous layered ocean model and corrects the classical KdV equation to the Generalized KdV (Generalized Kdv, GKdv for short) taking into account the changes in the background flow field in the model. Fan et al (2008a, b) utilizes GKdV to find that the flow direction and vertical distribution of the background positive pressure rising current and the background positive pressure falling current are obviously different in the process of researching propagation of the internal tide and the internal solitary wave in the north of the south China sea. They pointed out that in wide open sea areas, the role of the background flow field during propagation of internal tidal waves and isolated waves is very important and that it is necessary to distinguish the different roles of background positive pressure falling currents from rising currents.
At present, the research on the action of internal waves on marine structures is still in a step-by-step exploration stage, and the understanding on the action mechanism and the influence mechanism of the internal waves is still limited. Yeung et al (1999) solved the radiation and diffraction problems of rectangular structures in two layers of fluid at finite water depths using an integral equation based on singularity distribution. Cai et al (2003,2008) analyze and simulate according to the measured data of the internal solitary wave in the north of the south China sea and the weight coefficient to obtain the upper wave induced flow field when the internal wave passes through, and propose to calculate the acting force and moment of the internal wave on the seabed pile by using the Morison formula, and find that the acting force of the internal solitary wave on the pile is far greater than the acting force of the surface wave. The leaf spring et al (2005) introduces a surface wave Morison formula, solves the load of the internal wave acting on the small-scale cylinder at different water depths and frequencies, and gives the characteristic of vertical distribution of the load. Weigang et al (2007) studied the reflection and transmission laws of internal solitary waves on a submerged vertical sheet using an asymptotic matching method. The problem of the motion response of the SPAR platform in two layers of fluid under the action of internal waves was studied by Heterokon et al (2008). Sun and Huang (2012) iteratively calculates the internal wave force of S-Spar using a flexible rod Morison equation, and studies the motion response of the S-Spar platform under the action of the internal wave. Guo et al (2013) studied the extreme response of a top tension riser under solitary wave action in south China sea based on the KdV equation.
With the rapid development of Computational Fluid Dynamics (CFD), CFD technology is adopted to study the effect of internal waves on marine structures, which is also called a research hotspot. In particular, (2008) a numerical water tank is established based on an N-S equation, and numerical simulation is carried out on the acting force of a small-scale horizontal cylinder in a density stratification fluid fluctuation field. Based on an N-S equation, Futongming et al (2009) combined with an internal solitary wave KdV and an mKdv theory, developed a double push plate numerical wave-making method, which is well matched with solutions of KdV and the mKdv theory. Yunxiang et al (2010) researches the load and motion response of a tension leg platform in solitary waves in the ocean by adopting a time domain finite displacement motion equation and combining an improved Morison formula. Liu Biluo et al (2011) performed numerical wave generation by applying a velocity entry wave generation method according to an mKdv theory, and studied the interaction between an internal solitary wave and a top tension riser. Nishu et al, (2011) studied the effect of internal waves on the motion response of floating structures and mooring systems using the Sesam software. Plateau snow and the like (2012) establish an internal solitary wave numerical water tank simulation method through secondary development of commercial software FLUENT based on MCC theoretical solution. Friendship, etc. (2013) are based on FLUENT software, and the generation and evolution of the elliptic cosine internal wave and the action of the elliptic cosine internal wave and pier columns with different shapes in different arrangement modes are numerically simulated, researched and analyzed by adopting an N-S equation and a VOF method.
As described above, one of the numerical studies of internal waves is a numerical mode study in a large scale, which is mainly used for simulating the generation, propagation and dissipation processes of internal waves in an actual marine environment, and the result is closer to the internal wave environment under the actual condition (considering factors such as a background flow field), but the grid density is often large, and the action condition of the internal waves on the marine structure cannot be calculated. The other is a computational fluid mechanics internal wave water tank under the small scale, which is mainly used for computing the characteristics of internal waves under the small scale condition and the characteristics of interaction of the internal waves and a structure, and is finer than a large scale numerical mode, but the internal waves manufactured in the small scale internal wave water tank are usually made by a theoretical method, and the stress condition of the structure under the real internal wave environment cannot be computed no matter the waveform and the speed field of the internal waves are greatly different from the actual condition.
Disclosure of Invention
The invention aims to solve the defects in the prior art, and provides a new reference for the ocean engineering design in south China sea by realizing the wave generation by considering the internal wave numerical value of the background flow field through the numerical simulation of the south China sea three-dimensional flow field and the secondary development of the CFD technology and analyzing the stress characteristic of the ocean structure in the internal wave environment through the internal wave numerical value experiment.
An internal solitary wave action force characteristic analysis method considering a background flow field comprises the following steps:
step 1: performing numerical simulation on the south-sea circulation by using a three-dimensional ocean numerical model;
step 2: establishing an internal wave numerical value water tank;
and step 3: the effect of internal waves on the marine structure is determined by considering the internal wave numerical water tank and the marine structure network model of the background process.
Further, in the analysis method as described above, the step 1 includes: and performing numerical simulation on the south-sea circulation by using a three-dimensional ocean numerical model ROMS based on the actual temperature, salinity, depth, atmospheric forcing, precipitation, heat flux and other basic data of the south sea to obtain a continuous layered three-dimensional flow field structure of the south sea.
Further, in the analysis method as described above, the step 2 includes: and (3) carrying out two-dimensional water tank numerical value wave-making method research by adopting a Computational Fluid Dynamics (CFD) technology and utilizing a UDF secondary development technology, and establishing an internal wave numerical value water tank. In order to obtain the waveform of the internal wave on the fluid interface, the VOF method is adopted to track the change of the waveform of the internal interface. And meanwhile, the numerical dissipation model is adopted to perform internal wave elimination, the RANS equation is taken as a control equation, and a CFD (computational fluid dynamics) method is adopted to perform numerical simulation on the propagation of the internal solitary wave in the numerical water tank by combining a k-epsilon turbulence mode.
Further, in the analysis method as described above, the step 3 includes: taking a continuous layered three-dimensional flow field obtained by simulation based on a three-dimensional ocean numerical model as a background field, respectively carrying out vector averaging on the induced velocities of an upper mixing layer and a lower deep sea layer, taking the average horizontal velocity in the two layers of fluid as a motion velocity, defining the velocity at the boundary condition of a velocity inlet, carrying out wave generation by using a velocity inlet wave generation method, and constructing an internal wave numerical water tank considering the background flow field;
and selecting a proper grid according to the key geometric parameters of the ocean structure to establish an ocean structure surface model. Analyzing the distribution characteristics of the internal wave velocity field on the surface of the ocean structure by using an internal wave numerical water tank; and combining with a Morison formula, carrying out numerical simulation and analysis on the surface pressure distribution of the ocean structure under the action of the internal wave and the load characteristic thereof, and realizing the analysis of the action force characteristic of the internal solitary wave under the consideration of a background flow field.
The invention solves the problem that the background flow field can not be considered by the internal wave-making method, and combines the internal wave ocean mode, the internal wave computational fluid mechanics method and the internal wave acting force theoretical method for the first time to form a complete computing system of the internal wave-making method and the force measuring method which consider the background flow field. The method can enable the research on the effect of the internal wave on the structure to be closer to the actual situation, and can play a guiding role in the calculation of the safety load and the structural design of the offshore structure.
Drawings
FIG. 1 is a flow chart of the analysis method of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention are described below clearly and completely, and it is obvious that the described embodiments are some, not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
At present, the internal wave research method is limited to large-scale or small-scale research, and the combination degree of theoretical research and numerical research is low. An algorithm capable of combining a large-scale numerical model with small-scale numerical calculation and a theoretical method is set forth, so that an internal wave environment in an actual marine environment is effectively manufactured by using a numerical method in a small-scale environment, and a load generated by an internal wave is calculated by using a theoretical method of improving a Morrison equation.
The invention provides an analysis method for the action force characteristic of an internal solitary wave under the consideration of a background flow field, which comprises the following steps:
step 1: numerical simulation of south-sea circulation by using three-dimensional ocean numerical model
Specifically, atmospheric forcing data is provided for the ROMS mode by using meteorological data; providing a boundary field and an initial field for the ROMS mode by using the ocean atmospheric data such as the temperature, the salinity, the precipitation, the heat flux and the like of the climate state; the tide compulsive data is provided by using the harmonic constants of 8 main partial tides provided by the tide harmonic analysis result calculated by the numerical assimilation model of offshore tide in China; numerical mode data calculation of ocean flow field in south China sea is completed by Linux workstation
Step 2: establishing an internal wave numerical value water tank;
specifically, the numerical water tank is established by using FLUENT software as a CFD platform. However, FLUENT software itself does not have the internal wave generation technology. Therefore, the internal wave generation considering the background flow field needs to be realized by secondarily developing FLUENT through an open source interface of the software, namely a user self-definition function (UDF). Specifically, the method is used for simulating the internal wave environmental parameters in the large-scale ocean by using the ROMS to simulate the internal wave velocity field with the background flow field. The target region velocity field time series is then extracted and compiled into a c-language form that can be recognized by FLUENT. And then, defining the inlet speed of the numerical water tank by using the compiled speed field as a speed inlet boundary condition by using the user-defined function of FLUENT, thereby realizing numerical water tank wave generation of the internal solitary wave. Besides the speed inlet boundary condition adopted at the inlet, the upper, lower, left and right boundaries of the numerical water tank adopt fixed wall boundaries, and the outlet adopts the outflow boundary condition.
And 3, determining the effect of the internal wave on the ocean structure by considering the internal wave numerical value water tank and the ocean structure network model of the background process.
In particular, a principle step is shown in which the background flow field is considered. The ocean structure grid model is characterized in that different forms of grids are divided according to different forms of ocean structures, and the grids comprise regular grids, irregular grids and the like. And finally substituting the speed of grid nodes around the structure into a Morrison equation to calculate the acting force of the internal wave on the structure in the background flow environment.
The technical scheme of the invention is elaborated as follows:
the method specifically comprises the following steps:
(1) and performing numerical simulation on the south-sea circulation by using a three-dimensional ocean numerical mode based on the actual temperature, salinity and depth of the south sea and the basic data such as atmospheric forcing, precipitation, heat flux and the like to obtain the continuous layered south-sea three-dimensional flow field structure. The three-dimensional ocean numerical mode is a ROMS.
(2) And (3) carrying out two-dimensional water tank numerical value wave-making method research by adopting a Computational Fluid Dynamics (CFD) technology and utilizing a UDF secondary development technology, and establishing an internal wave numerical value water tank. In order to obtain the waveform of the internal wave on the fluid interface, the VOF method is adopted to track the change of the waveform of the internal interface. And meanwhile, the numerical dissipation model is adopted to perform internal wave elimination, the RANS equation is taken as a control equation, and a CFD (computational fluid dynamics) method is adopted to perform numerical simulation on the propagation of the internal solitary wave in the numerical water tank by combining a k-epsilon turbulence mode.
Specifically, the numerical water tank is established by using FLUENT software as a CFD platform. However, FLUENT software itself does not have the internal wave generation technology. Therefore, the internal wave generation considering the background flow field needs to be realized by secondarily developing FLUENT through an open source interface of the software, namely a user self-definition function (UDF). Specifically, the method is used for simulating the internal wave environmental parameters in the large-scale ocean by using the ROMS to simulate the internal wave velocity field with the background flow field. The target region velocity field time series is then extracted and compiled into a c-language form that can be recognized by FLUENT. And then, defining the inlet speed of the numerical water tank by using the compiled speed field as a speed inlet boundary condition by using the user-defined function of FLUENT, thereby realizing numerical water tank wave generation of the internal solitary wave. Besides the speed inlet boundary condition adopted at the inlet, the upper, lower, left and right boundaries of the numerical water tank adopt fixed wall boundaries, and the outlet adopts the outflow boundary condition.
The VOF is an abbreviation of phase volume fraction method, which means that the interface between two different material phases or the same material different density phases is marked and identified by a mathematical means in a discrete control domain of computational fluid dynamics. The specific principle can be briefly described as follows: in a certain grid control area, the volume fraction of a material phase in the area is defined, and the fraction values are 0-1, 0 and 1 respectively represent two different phases. The phase volume fraction of the interface between the two materials should be a value between 0 and 1, and the specific position of the interface is found by analyzing the fraction and utilizing an interpolation method. When all the grids are defined, a continuous interface form can be embodied by the VOF method.
The VOF method is currently the most commonly used method for calculating multiphase flow values. In the method, because internal waves are generated in density layered water bodies, the water body densities of the upper and lower sides of a density jump layer are different, the upper and lower water bodies are defined as two different fluid phases by using a VOF (voltage induced degradation) method, and the interface between the two phases is tracked by using the VOF method in the whole calculation. The purpose is to record the waveform change of the interface, but to determine the velocity field of the internal wave, because we know that the velocities of the upper layer and the lower layer of the internal wave are different in magnitude and opposite in direction, and if the interface is not determined, the velocity distribution cannot be known.
(3) The method comprises the steps of taking a continuous layered three-dimensional flow field obtained based on three-dimensional ocean numerical model simulation as a background field, respectively carrying out vector averaging on speeds of an upper mixing layer and a lower deep sea layer induced by the continuous layered three-dimensional flow field, taking an average horizontal speed in two layers of fluid as a movement speed, defining a speed at a speed inlet boundary condition, carrying out wave generation by using a speed inlet wave generation method, and constructing an internal wave numerical water tank considering the background flow field.
(4) And selecting a proper grid according to the key geometric parameters of the ocean structure to establish an ocean structure surface model. Analyzing the distribution characteristics of the internal wave velocity field on the surface of the ocean structure by using an internal wave numerical water tank; and combining with a Morison formula, carrying out numerical simulation and analysis on the surface pressure distribution of the ocean structure under the action of the internal wave and the load characteristic thereof, and realizing the analysis of the action force characteristic of the internal solitary wave under the consideration of a background flow field.
ROMS ocean numerical model
The ROMS is called as a Regional Ocean mode System (Regional Ocean Modeling System), is an open-source three-dimensional Regional Ocean model, and is a newly developed free sea surface, terrain following and three-dimensional nonlinear slope pressure original equation mode. A new high-order horizontal pressure gradient algorithm is used in the ROMS mode, and compared with the horizontal pressure gradient algorithm, the error accumulation caused by mode calculation can be effectively reduced. The ROMS ocean model also incorporates many new technologies, including new sub-grid parameterization schemes and many other new modules.
(1) The ROMS mode has the main characteristics that:
① adopts static force hypothesis and Boussinesq approximation, internal and external mode splitting technology, so that the external mode can simulate the physical phenomenon of a small surface scale by adopting a short time step.
② mode uses a free surface, close to reality.
③ sigma (near bottom) coordinate system, can handle significant terrain variations, such as at land-frame slopes, sea-bottom ridges, which is important for studying shallow sea physical marine processes driven by tides.
④ support parallel (MPI, OPENMP) operation, so that the mode can obtain better performance on various supercomputers and execute large mode calculation tasks.
The ROMS mode has strong functions and wide application range, and is widely applied to researching the aspects of ocean circulation, ocean-gas interaction, internal wave, mixing and the like. The model also has some other expanded functions, such as sea ice model package, wave model wave, atmosphere model package, open boundary condition model package, etc., so that the model can be applied to corresponding research through simple modification.
(2) Basic control equation set
Equation of motion of
The equation of state is
ρ＝ρ(T,S,P) (4)
Equation of temperature control
Salinity control equation
Equation of continuity
Making the system of equations solvable by parameterization of Reynolds stress and turbulent tracing flux
In the formula, Du, Dv, DT, DS are diffusion terms; fu, Fv, FT, FS are forcing terms; f (x, y) is a Coriolis force parameter; g is the acceleration of gravity; phi (x, y)Z, t) is the dynamic pressure, which is equal to P/rho0P is total pressure; rho0+ ρ (x, y, z, t) is the total density; s (x, y, z, t) is salinity; t (x, y, z, T) is the temperature; ζ (x, y, z, t) is the surface water level; KM is the vertical turbulence viscosity coefficient; KC vertical turbulence diffusion coefficient.
In order to save time, the ROMS adopts a mode separation technique to decompose the motion equation into a motion equation of vertical integral (two-dimensional mode) and a motion equation of three-dimensional structure (three-dimensional mode). This allows the two-dimensional equation for calculating the free surface to be derived from the whole
And separating the equation set, wherein a smaller time step length is adopted, and a larger step length is adopted for the calculation of the three-dimensional flow field. That is, a two-dimensional system of equations is integrated over several steps, and then a three-dimensional system of equations is integrated over one step.
(3) Boundary condition
Vertical boundary condition
When z is ζ (x, y, t), the boundary conditions on the mode are:
when z is-h (x, y), the boundary conditions under the mode are:
in the formula, Ts x，Ts yIs the sea surface wind stress; qTIs the sea surface heat flux; E-P is the difference between the evaporation and precipitation; t isrefIs the sea surface reference temperature.
The boundary condition of the horizontal side boundary condition at the solid wall is that the normal velocity component is zero. At the boundary of north and south, U is 0, and at the boundary of east and west, V is 0.
(4) Sigma coordinate system
In order to improve the calculation efficiency and avoid wasting calculation grids, the ROMS adopts orthogonal curve grids to fit the irregular change of a coastline in the horizontal direction, adopts a Sigma coordinate system in the vertical direction, controls the vertical coordinate scale within the range of-1 to 0 through a vertical transformation function and a stretching function, can adjust the density between layers, and carries out uniform or non-uniform layering according to research contents. The following conversion relationship exists between the vertical physical coordinate z of the Cartesian coordinate system and the vertical coordinate s of the Sigma coordinate system:
z＝z(x,y,s) (22)
where z is the height of the cartesian coordinate system and s is the vertical distance from the water surface, for example, 1 ≦ s ≦ 0, s ≦ 0 representing the free surface, z ═ η, s ═ 1 representing the sea floor, z ═ h (x, y) the ROMS gives 2 transfer functions and 4 stretch functions for the user to choose the appropriate combination to use.
Internal wave numerical theory
For two layers of fluid that are continuously incompressible, the density of the upper and lower layers of fluid, respectively, can be defined as ρiI is 1, 2, and the velocity field in the cartesian coordinate system is defined as
The pressure in the entire flow field needs to satisfy the equation of continuity and the equation of momentum.
The governing equation in a numerical inner wave flume can be expressed in the form:
uix+viy+wiz＝0 (23)
the subscript i is 1 and 2 indicates the upper and lower layer fluids.
The pressure and velocity in the above equation should satisfy the continuity condition at the upper and lower fluid interfaces, and define the fluid stratification interface as ζ, then:
ζt+u1ζx＝w1，ζt+u2ζx＝w2，p1＝P2at z＝ζ (27)
according to the assumption of the rigid-cap theorem, the top free liquid surface is assumed to be a rigid surface and the bottom surface is assumed to be a rigid bottom surface, at these two boundaries, the velocity flux is 0:
w1(x，h1，t)＝0，w2(x，-h2，t)＝0 (28)
the sink side is defined as a smooth rigid surface for simulating the glass boundary in a physical sink, then this boundary should satisfy the impermeability condition:
we use lagrange fluid volume method (VOF), which assumes a fluid laminar interface as a linear plane, to track the two-layer fluid internal interface. Different fluid terms are represented by setting a VOF function a (x, y, z, t) to 1 or 0 at the interface grid. The function should satisfy the following relation:
at+aux+avy+awz＝0 (30)
the turbulence model in the calculation adopts a recombination k-epsilon turbulence model (RNG k-epsilon) to describe turbulence action, and the turbulence kinetic energy k transport equation and the dissipation rate epsilon can be expressed as follows:
wherein p isTIs energy of turbulence, DkAnd DεIs a dissipative term.
For the acting force of the internal solitary wave on the structure, the acting force can be obtained by integrating the pressure difference force and the viscous force in the momentum conservation equation, and therefore, in a cartesian coordinate system, the acting force of the fluid on the structure can be expressed as:
fx＝μ∫[2uixx+(vx+uy)y+(wx+uz)z]dsx+∫pixdsx(32)
fy＝μ∫[2viyy+(vx+uy)x+(wy+vz)z]dsy+∫Piydsy(33)
fz＝μ∫[2wizz+(wx+uz)x+(wy+vz)y]dsz+∫pizdsz(34)
the viscous force is generated by the viscous effect of the fluid, and the differential pressure is generated by the pressure of the fluid, which can be expressed as:
in the formula (f)x，fy，fz) Representing fluid forces in three directions (x, y, z),(s)x，sy，sz) Representing the frontal area of the structure in three directions.
Morison formula
In the actual ocean engineering, Morison et al propose to decompose the wave force borne by a cylindrical object in seawater into the algebraic sum of two terms, drag force and inertia force, in the form of,
where p (t) represents the force load per unit length of the pile. The drag coefficient Cd and the inertia coefficient Cm are determined experimentally and are closely related to a series of parameters: KC (Keulegan-Carpenter) number, Reynolds number, and relative roughness k/D, where k is the average roughness and D is the diameter.
The Morison formula is used as a semi-empirical semi-theoretical method, has a wide application range, is suitable for the stress of small-diameter piles in a regular wave field, and can be used when the diameter of a stand column is small compared with the wavelength of internal waves when the internal wave acting force borne by an ocean structure is calculated
Native three-dimensional ocean numerical patterns, computational fluid dynamics, and Morisen's equations are three essentially unrelated concepts. Previous research methods have also studied and processed internal waves separately in three areas. However, in actual situations, in order to more accurately calculate the effect of the internal wave on the structure in the actual sea state, it is necessary to consider the case where the background flow field and the internal wave act simultaneously. The invention provides a solution to this problem by combining the two numerical methods and a theoretical method through specific algorithms and programs, which can not only take into account the effect of large-scale internal waves, but also simulate the effect of internal waves on the structure under the condition of small scale.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (2)
1. An analysis method for internal solitary wave action force characteristics under the consideration of a background flow field is characterized by comprising the following steps:
step 1: performing numerical simulation on the south-sea circulation by using a three-dimensional ocean numerical model ROMS;
step 2: establishing an internal wave numerical value water tank;
and step 3: determining the effect of the internal wave on the ocean structure by considering the internal wave numerical water tank and the ocean structure network model of the background process;
the step 1 comprises the following steps: performing numerical simulation on the south-sea circulation by using a three-dimensional ocean numerical model ROMS based on the actual temperature, salinity and depth of the south sea and atmospheric forcing, precipitation and heat flux to obtain a continuous layered three-dimensional flow field structure of the south sea;
the step 3 comprises the following steps: taking a continuous layered three-dimensional flow field obtained by simulation based on a three-dimensional ocean numerical model as a background field, respectively carrying out vector averaging on the induced velocities of an upper mixing layer and a lower deep sea layer, taking the average horizontal velocity in the two layers of fluid as a motion velocity, defining the velocity at the boundary condition of a velocity inlet, carrying out wave generation by using a velocity inlet wave generation method, and constructing an internal wave numerical water tank considering the background flow field;
selecting a proper grid according to the key geometric parameters of the ocean structure, and establishing an ocean structure surface model; analyzing the distribution characteristics of the internal wave velocity field on the surface of the ocean structure by using an internal wave numerical water tank; and combining with a Morison formula, carrying out numerical simulation and analysis on the surface pressure distribution of the ocean structure under the action of the internal wave and the load characteristic thereof, and realizing the analysis of the action force characteristic of the internal solitary wave under the consideration of a background flow field.
2. The analytical method of claim 1, wherein step 2 comprises: adopting a computational fluid mechanics technology and utilizing a UDF secondary development technology to carry out research on a two-dimensional water tank numerical wave making method and establish an internal wave numerical water tank; in order to obtain the waveform of the internal wave on the fluid interface, the change of the waveform of the internal interface is tracked by adopting a VOF method; and meanwhile, the numerical dissipation model is adopted to perform internal wave elimination, the RANS equation is taken as a control equation, and a CFD (computational fluid dynamics) method is adopted to perform numerical simulation on the propagation of the internal solitary wave in the numerical water tank by combining a k-epsilon turbulence mode.
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| CN117313587B (en) * | 2023-11-28 | 2024-02-06 | 西北工业大学 | Method and system for simulating interaction between internal solitary wave and background shear flow |
| CN117890080B (en) * | 2024-03-15 | 2024-05-28 | 中国海洋大学 | Method for simulating wave generation of solitary waves in shutter door rotating ocean |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103063253A (en) * | 2012-12-27 | 2013-04-24 | 清华大学深圳研究生院 | Multi-sending and multi-receiving acoustic measurement method for oceanic internal waves |
| CN103454064A (en) * | 2013-09-18 | 2013-12-18 | 中国海洋大学 | First modality internal wave generator |
| CN107218931A (en) * | 2017-05-23 | 2017-09-29 | 广东贝达海洋科学有限公司 | A kind of internal wave of ocean early warning system and method based on online monitoring data |
| CN108595831A (en) * | 2018-04-22 | 2018-09-28 | 天津大学 | It is a kind of to calculate the mixed Dynamic Simulation Method of tide cause in real time |
| CN108829918A (en) * | 2018-04-28 | 2018-11-16 | 中国海洋大学 | Intelligent buoy networking simulating method and system towards oceanographic phenomena |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105205200A (en) * | 2015-04-27 | 2015-12-30 | 河海大学 | Verification method for silt coast wave-induced current numerical simulation |
| CN106596046B (en) * | 2016-12-30 | 2019-10-11 | 中国海洋大学 | A kind of stress observation device of marine structure under interior estimates environment |
| CN108254157B (en) * | 2018-02-06 | 2019-09-03 | 中国海洋大学 | A kind of experimental system of interior wave and submerged body interaction |
-
2019
- 2019-03-01 CN CN201910154630.7A patent/CN110008509B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103063253A (en) * | 2012-12-27 | 2013-04-24 | 清华大学深圳研究生院 | Multi-sending and multi-receiving acoustic measurement method for oceanic internal waves |
| CN103454064A (en) * | 2013-09-18 | 2013-12-18 | 中国海洋大学 | First modality internal wave generator |
| CN107218931A (en) * | 2017-05-23 | 2017-09-29 | 广东贝达海洋科学有限公司 | A kind of internal wave of ocean early warning system and method based on online monitoring data |
| CN108595831A (en) * | 2018-04-22 | 2018-09-28 | 天津大学 | It is a kind of to calculate the mixed Dynamic Simulation Method of tide cause in real time |
| CN108829918A (en) * | 2018-04-28 | 2018-11-16 | 中国海洋大学 | Intelligent buoy networking simulating method and system towards oceanographic phenomena |
Non-Patent Citations (5)
| Title |
|---|
| Study of Surface Wave Characteristics and Extreme Parameters Estimation in a Port With Submerged Breakwater;Wang Z, Dong S, Dong X, et al.;《ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering》;20161231;全文 * |
| 内孤立波作用下小尺度竖直圆柱体的水动力特性研究;王飞;《中国博士学位论文全文数据库工程科技II辑》;20161031;第1、5-6章 * |
| 地形和层结变化对内潮生成影响的数值模拟研究;刘昆; 徐振华; 尹宝树;《海洋科学》;20161115;全文 * |
| 存在背景流的内波场中隔水管涡激振动研究;王琮，刘振纹;《哈尔滨工程大学学报》;20180930;第39卷(第9期);全文 * |
| 近10年来南海孤立内波的研究进展;蔡树群, 何建玲, 谢皆烁;《地球科学进展》;20110731;第26卷(第7期);全文 * |
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