CN115659876A - Method for calculating vertical damping coefficient of heave plate of floating structure - Google Patents

Method for calculating vertical damping coefficient of heave plate of floating structure Download PDF

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CN115659876A
CN115659876A CN202211679510.7A CN202211679510A CN115659876A CN 115659876 A CN115659876 A CN 115659876A CN 202211679510 A CN202211679510 A CN 202211679510A CN 115659876 A CN115659876 A CN 115659876A
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damping coefficient
damping
coefficient
calculating
heave plate
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CN115659876B (en
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徐琨
白浩哲
李华军
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Ocean University of China
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Ocean University of China
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Abstract

The invention relates to the technical field of ocean engineering, and discloses a method for calculating a vertical damping coefficient of a heave plate of a floating structure, which comprises the following steps: s1, estimating an initial damping coefficient
Figure 76428DEST_PATH_IMAGE001
(ii) a S2, calculating a secondary damping coefficient
Figure 727989DEST_PATH_IMAGE002
And a hydrodynamic coefficient; s3, calculating the vertical speed time course of the heave plate
Figure 570043DEST_PATH_IMAGE003
And the vertical velocity time course of the water particles at the heave plate
Figure 309460DEST_PATH_IMAGE004
(ii) a S4, calculating the damping coefficient of each period in the time course
Figure 592674DEST_PATH_IMAGE005
And damping force
Figure 8612DEST_PATH_IMAGE006
(ii) a S5, calculating the damping force energy of the whole time course
Figure 744486DEST_PATH_IMAGE007
And damping coefficient
Figure 520550DEST_PATH_IMAGE008
(ii) a S6, adjusting the damping coefficient
Figure 658271DEST_PATH_IMAGE008
And comparing the initial damping coefficient with the initial damping coefficient, and outputting the vertical damping coefficient of the heave plate. The method solves the problems that the damping coefficient is difficult to calculate and the calculation structure is not accurate enough, considers the influence of the flow field flow velocity on the damping coefficient, better accords with the physical law, and has high calculation efficiency and accuracy.

Description

Method for calculating vertical damping coefficient of heave plate of floating structure
Technical Field
The invention relates to the technical field of ocean engineering, in particular to a method for calculating a vertical damping coefficient of a heave plate of a floating structure.
Background
Today, the offshore wind power industry is growing rapidly, and with increasing water depth, floating structures are becoming more cost-effective options, such as floating wind turbines. The floating body of most floating fans today comprises stand, flotation pontoon and the board that sways that dangles, and the board that dangles has played the increase damping at floating fan heaving, the pitching motion in-process, increases energy dissipation and then reduces the effect of floating fan motion, and the reasonable damping coefficient that sets up the board that sways that dangles becomes the key of the effective evaluation board drag-increase effect that sways.
In the prior art, a CFD method or a physical model test method is generally adopted for determining the damping coefficient, the CFD method is limited by the calculation effectiveness of the existing computer, the calculation is time-consuming, and the physical model test method is limited by the test expenditure and the test field and is difficult to develop, so that the damping coefficient can only refer to the recommended value of the damping coefficient of the regular structure in the specification under many conditions, and the requirement of accurate simulation is far from being met.
In view of the above, it is desirable to provide a method for calculating the vertical damping coefficient of a heave plate of a floating structure that addresses the above-identified problems of the prior art.
Disclosure of Invention
The invention provides a method for calculating a vertical damping coefficient of a heave plate of a floating structure, which solves the problems that the damping coefficient is difficult to calculate and the calculation structure is not accurate enough.
In order to solve the technical problems, the invention adopts the following technical scheme:
a method for calculating the vertical damping coefficient of a heave plate of a floating structure comprises the following steps:
s1, estimating an initial damping coefficient according to environmental conditions
Figure 162453DEST_PATH_IMAGE001
；
S2, according to the initial damping coefficient
Figure 244678DEST_PATH_IMAGE001
Calculating the secondary damping coefficient
Figure 450532DEST_PATH_IMAGE002
While simultaneously measuring the initial damping coefficient
Figure 816660DEST_PATH_IMAGE001
Leading the water power coefficient into a frequency domain to calculate the water power coefficient;
s3, calculating the secondary damping coefficient
Figure 512083DEST_PATH_IMAGE002
And guiding the hydrodynamic force coefficient into a time domain calculation program to carry out simulation calculation to obtain the vertical speed time course of the heave plate
Figure 222550DEST_PATH_IMAGE003
And the vertical velocity time course of the water particles at the heave plate
Figure 91149DEST_PATH_IMAGE004
；
S4, calculating the damping coefficient of each period in the time course according to the simulation result in the step S3
Figure 203462DEST_PATH_IMAGE005
And damping force
Figure 86098DEST_PATH_IMAGE006
；
S5, according to the damping force in the step S4
Figure 408495DEST_PATH_IMAGE006
Calculating the damping force energy of the whole time course
Figure 956151DEST_PATH_IMAGE007
And use damping force energy
Figure 296872DEST_PATH_IMAGE007
Calculating the damping coefficient of the whole time course
Figure 537360DEST_PATH_IMAGE008
；
S6, comparing the damping coefficient in the step S5
Figure 81474DEST_PATH_IMAGE008
Comparing the damping coefficient with the initial damping coefficient in the step S1, and if the damping coefficient is different from the initial damping coefficient
Figure 432821DEST_PATH_IMAGE009
If the damping coefficient is less than the threshold value, the damping coefficient is output
Figure 129512DEST_PATH_IMAGE008
Is the vertical damping coefficient of the heave plate, otherwise the damping coefficient
Figure 540902DEST_PATH_IMAGE008
Enter an iterative procedure to a difference value
Figure 244416DEST_PATH_IMAGE009
Less than the threshold.
In some embodiments of the present invention, the iterative procedure in step S6 is:
setting the initial damping coefficient in the step S2
Figure 258508DEST_PATH_IMAGE001
Is replaced with the damping coefficient
Figure 199920DEST_PATH_IMAGE008
Repeating the steps S2-S5 to obtain the damping coefficient
Figure 382812DEST_PATH_IMAGE010
Then comparing the damping coefficients
Figure 901518DEST_PATH_IMAGE010
And
Figure 594667DEST_PATH_IMAGE011
when difference value
Figure 921744DEST_PATH_IMAGE009
When the damping coefficient is less than the threshold value, the damping coefficient is output
Figure 550302DEST_PATH_IMAGE010
Is the vertical damping coefficient of the heave plate.
In some embodiments of the present invention, the step S1 specifically includes the following steps:
s11, estimating a motion response zeta of the heave plate in the heave direction according to the environment parameters;
s12, calculating an initial KC value according to the motion response zeta, wherein the calculation formula of the initial KC value is as follows:
Figure 431670DEST_PATH_IMAGE012
；
wherein D is the diameter of the heave plate;
s13, substituting the initial KC value in the step S12 into the following formula I to calculate the initial damping coefficient
Figure 53145DEST_PATH_IMAGE001
：
Figure 437990DEST_PATH_IMAGE013
。
In some embodiments of the invention, said secondary damping coefficient in said step S2
Figure 470405DEST_PATH_IMAGE014
The calculation formula of (c) is:
Figure 635808DEST_PATH_IMAGE015
；
wherein the content of the first and second substances,
Figure 670760DEST_PATH_IMAGE016
is the density of seawater.
In some embodiments of the invention, said hydrodynamic coefficient in said step S2 comprises wave power
Figure 300324DEST_PATH_IMAGE017
Additional mass
Figure 129740DEST_PATH_IMAGE018
And radiation damping
Figure 861067DEST_PATH_IMAGE019
。
In some embodiments of the invention, wave forces are obtained
Figure 699710DEST_PATH_IMAGE017
The calculation formula of (2):
Figure 855884DEST_PATH_IMAGE020
；
wherein, the first and the second end of the pipe are connected with each other,
Figure 246415DEST_PATH_IMAGE021
is the incident potential of the light beam, and,
Figure 324092DEST_PATH_IMAGE022
is the diffraction potential of the light beam,
Figure 74748DEST_PATH_IMAGE023
represents a unit normal vector of the vector,
Figure 554271DEST_PATH_IMAGE024
is the degree of freedom of the object and S represents a line infinitesimal.
Additional mass
Figure 115702DEST_PATH_IMAGE018
The calculation formula of (c):
Figure 477413DEST_PATH_IMAGE025
；
radiation damping
Figure 657859DEST_PATH_IMAGE019
The calculation formula of (2):
Figure 867255DEST_PATH_IMAGE026
；
wherein, the first and the second end of the pipe are connected with each other,
Figure 209374DEST_PATH_IMAGE027
is that
Figure 386278DEST_PATH_IMAGE028
The radiation potential of the direction of the radiation,
Figure 104835DEST_PATH_IMAGE029
the representation is taken in the real part,
Figure 932851DEST_PATH_IMAGE030
the representation takes the imaginary part.
In some embodiments of the invention, the damping coefficient of each period in said step S4
Figure 508189DEST_PATH_IMAGE005
The calculation process specifically comprises the following steps:
s41, calculating the relative heave velocity time course of the heave plate relative to the water particle according to the simulation result of the step S3
Figure 47755DEST_PATH_IMAGE031
；
S42, selecting the maximum relative heave speed time interval in each period T
Figure 429058DEST_PATH_IMAGE032
Post-calculation KC' value:
Figure 737679DEST_PATH_IMAGE033
；
s43, substituting the KC' value in the step S42 into a formula I to calculate a damping coefficient of each period
Figure 562547DEST_PATH_IMAGE005
：
Figure 323830DEST_PATH_IMAGE034
。
In some embodiments of the invention, the damping force of each cycle in said step S4
Figure 446507DEST_PATH_IMAGE006
The calculation formula of (2) is as follows:
Figure 734268DEST_PATH_IMAGE035
。
in some embodiments of the invention, the damping force energy in step S5
Figure 589092DEST_PATH_IMAGE007
By damping forces for each period T
Figure 477151DEST_PATH_IMAGE006
And performing time integration to obtain the target.
In some embodiments of the invention, the damping coefficient of the whole time interval in the step S5
Figure 341202DEST_PATH_IMAGE008
The calculation formula of (c) is:
Figure 155574DEST_PATH_IMAGE036
。
compared with the prior art, the technical scheme of the invention has the following technical effects:
the invention considers the influence of the flow velocity of the flow field on the damping coefficient for the calculation of the damping coefficient, can independently calculate the damping coefficient for the structures at different flow field positions, and better conforms to the physical law. I.e. the course of the damping coefficient leading into the vertical speed time course of the heave plate
Figure 837091DEST_PATH_IMAGE003
And the vertical velocity time course of the water particles at the heave plate
Figure 572966DEST_PATH_IMAGE004
(ii) a The method is based on potential flow calculation, has high calculation efficiency and fewer iteration times, and can quickly determine the vertical damping coefficient of the floating fan heave plate according to the environmental working condition.
In addition, the method has stronger robustness, namely the estimated dependency of the initial motion under a certain environment working condition is not strong, and even if the estimated initial damping coefficient deviation is larger, the finally obtained damping coefficient still has smaller deviation.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic perspective view of a method for calculating the vertical damping coefficient of a heave plate of a floating structure, as shown in the example.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "mounted," "connected," and "connected" are to be construed broadly and may include, for example, a fixed connection, a detachable connection, or an integral connection unless otherwise specifically stated or limited. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. In the foregoing description of embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.
Example 1
As shown with reference to figure 1 of the drawings,
a method for calculating the vertical damping coefficient of a heave plate of a floating structure comprises the following steps:
s1, estimating an initial damping coefficient according to environmental conditions
Figure 850495DEST_PATH_IMAGE001
；
Specifically, the method comprises the following steps:
s11, estimating a motion response zeta of the heave plate in the heave direction according to the environment parameters; the motion response ζ can be obtained according to engineering experience; theoretically, the selection of the motion response zeta has no direct influence on the final damping coefficient obtained according to the method, the robustness of the method is strong, namely the estimated dependency of the initial motion under a certain environment working condition is not strong, and even if the motion estimation deviation is large, the deviation of the final obtained damping coefficient is still small. If the damping coefficient is selected according to engineering experience, the iteration times of the damping coefficient can be effectively reduced, namely, the accurate damping coefficient can be obtained through less iteration;
s12, calculating an initial KC value according to the motion response zeta, wherein the KC value is a Keulegan-Carpenter (KC) value; the calculation formula of the initial KC value is as follows:
Figure 722636DEST_PATH_IMAGE012
；
wherein D is the diameter of the heave plate;
s13, substituting the initial KC value in the step S12 into the following formula I to calculate the initial damping coefficient
Figure 575054DEST_PATH_IMAGE001
：
Figure 798225DEST_PATH_IMAGE037
。
In particular, the initial damping coefficient
Figure 800816DEST_PATH_IMAGE001
The damping coefficient is estimated according to environmental parameters and engineering experience, and then is used as a reference value of the damping coefficient calculated for the first time. In addition, the formula is obtained by fitting according to the result of a physical model test.
S2, according to the initial damping coefficient
Figure 166944DEST_PATH_IMAGE001
Calculating the secondary damping coefficient
Figure 65630DEST_PATH_IMAGE002
While simultaneously applying the initial damping coefficient
Figure 635152DEST_PATH_IMAGE001
Leading the water power coefficient into a frequency domain to calculate the water power coefficient;
because the damping coefficient needs to be calculated by using the SIMA time domain calculation program, and because both the time domain parameters and the frequency domain parameters can influence the damping coefficient result, the input quantity of the time domain calculation program comprises the secondary damping coefficient in the time domain
Figure 379117DEST_PATH_IMAGE002
And hydrodynamic coefficients in the frequency domain.
Specifically, the secondary damping coefficient in the step S2
Figure 366796DEST_PATH_IMAGE002
The calculation formula of (c) is:
Figure 170804DEST_PATH_IMAGE015
；
wherein the content of the first and second substances,
Figure 493201DEST_PATH_IMAGE016
is the density of seawater.
The hydrodynamic coefficients in step S2 comprise wave forces
Figure 837594DEST_PATH_IMAGE017
Additional mass
Figure 804413DEST_PATH_IMAGE018
And radiation damping
Figure 153224DEST_PATH_IMAGE019
。
Wave force calculation formula:
Figure 572704DEST_PATH_IMAGE020
；
wherein the content of the first and second substances,
Figure 48685DEST_PATH_IMAGE038
is the incident potential of the light beam, and,
Figure 870010DEST_PATH_IMAGE039
is the diffraction potential of the light beam,
Figure 156766DEST_PATH_IMAGE040
represents a normal vector of the unit, and is,
Figure 860280DEST_PATH_IMAGE041
is the degree of freedom of the object and S represents a line infinitesimal.
Formula for the additional mass:
Figure 749738DEST_PATH_IMAGE025
；
calculation formula of radiation damping:
Figure 815783DEST_PATH_IMAGE026
；
wherein, the first and the second end of the pipe are connected with each other,
Figure 132495DEST_PATH_IMAGE027
is that
Figure 634890DEST_PATH_IMAGE028
The radiation potential of the direction of the radiation,
Figure 328039DEST_PATH_IMAGE029
the representation is taken in the real part,
Figure 248591DEST_PATH_IMAGE030
the representation takes the imaginary part.
S3, calculating the secondary damping coefficient
Figure 798521DEST_PATH_IMAGE002
And importing the hydrodynamic coefficients into a time domain calculation program; performing time domain simulation, and extracting the vertical speed time course of the heave plate according to the time domain simulation result
Figure 679889DEST_PATH_IMAGE003
And the vertical velocity time course of the water particles at the heave plate
Figure 786516DEST_PATH_IMAGE004
(ii) a Vertical speed time course of the heave plate under the action of wave force
Figure 171361DEST_PATH_IMAGE003
And the vertical velocity time course of the water particles at the heave plate
Figure 220089DEST_PATH_IMAGE004
All of which are periodically changed. The method considers the influence of the flow velocity of the flow field on the damping coefficient, can independently calculate the damping coefficient for the structures at different flow field positions, and better accords with the physical law.
S4, calculating the damping coefficient of each period in the time course according to the simulation result in the step S3
Figure 588753DEST_PATH_IMAGE005
And damping force
Figure 420443DEST_PATH_IMAGE006
；
In some embodiments of the invention, the damping coefficient of each period in said step S4
Figure 299275DEST_PATH_IMAGE005
The calculation process specifically comprises the following steps:
s41, calculating the relative heave velocity time course of the heave plate relative to the water particle according to the simulation result of the step S3
Figure 394270DEST_PATH_IMAGE031
(ii) a Using relative speed time course
Figure 109285DEST_PATH_IMAGE042
As a calculation parameter, the heave speed time course of the water particles at the heave plate is avoided
Figure 682349DEST_PATH_IMAGE004
The influence on the calculation of the damping coefficient improves the accuracy of the calculation result of the damping coefficient.
S42, selecting the maximum relative heave speed time interval in each period T
Figure 182732DEST_PATH_IMAGE032
Post-calculation KC' value:
Figure 245366DEST_PATH_IMAGE033
；
s43, substituting the KC' value in the step S42 into a formula I to calculate a damping coefficient of each period
Figure 323043DEST_PATH_IMAGE005
：
Figure 90011DEST_PATH_IMAGE034
。
In some embodiments of the invention, the damping force of each cycle in said step S4
Figure 303954DEST_PATH_IMAGE006
The calculation formula of (c) is:
Figure 114653DEST_PATH_IMAGE035
。
s5, according to the damping force in the step S4
Figure 679627DEST_PATH_IMAGE006
Calculating the damping force energy of the whole time course
Figure 391231DEST_PATH_IMAGE007
And use damping force energy
Figure 115473DEST_PATH_IMAGE007
Calculating the damping coefficient of the whole time course
Figure 723172DEST_PATH_IMAGE008
；
Wherein the damping force is energy
Figure 385229DEST_PATH_IMAGE007
By damping forces for each period T
Figure 103786DEST_PATH_IMAGE006
And performing time integration to obtain the target.
Damping coefficient of the whole time course
Figure 354639DEST_PATH_IMAGE008
The calculation formula of (c) is:
Figure 257873DEST_PATH_IMAGE036
。
s6, comparing the damping coefficient in the step S5
Figure 797438DEST_PATH_IMAGE008
Comparing with the initial damping coefficient in the step S1, and if the difference value is larger than the initial damping coefficient
Figure 428009DEST_PATH_IMAGE009
If the damping coefficient is less than the threshold value, the damping coefficient is output
Figure 736630DEST_PATH_IMAGE008
Is the vertical damping coefficient of the heave plate, otherwise the damping coefficient
Figure 810766DEST_PATH_IMAGE008
Enter an iterative procedure to difference
Figure 368786DEST_PATH_IMAGE009
Less than the threshold.
For the determination of the threshold, other data are generally accurate to one decimal place, so the threshold is in the range of (0, 0.1), specifically, the threshold is 0.1.
In some embodiments of the present invention, the iterative procedure in step S6 is:
the damping coefficient calculated through the steps S2 to S5 for the first time
Figure 694725DEST_PATH_IMAGE008
Is marked as
Figure 733219DEST_PATH_IMAGE043
；
The initial damping coefficient in the step S2
Figure 588043DEST_PATH_IMAGE001
Replacing the damping coefficient
Figure 226835DEST_PATH_IMAGE043
Then, repeating the steps S2-S5 to obtain the damping coefficient
Figure 90885DEST_PATH_IMAGE044
Then calculating the damping coefficient
Figure 482421DEST_PATH_IMAGE044
And
Figure 39305DEST_PATH_IMAGE043
difference of (2)
Figure 571917DEST_PATH_IMAGE009
When difference is between
Figure 98713DEST_PATH_IMAGE009
When the damping coefficient is less than the threshold value, the damping coefficient is output
Figure 236434DEST_PATH_IMAGE044
The vertical damping coefficient of the heave plate is shown; otherwise damping coefficient
Figure 839584DEST_PATH_IMAGE044
Continuing to iterate until the damping coefficient
Figure 531597DEST_PATH_IMAGE010
And
Figure 127663DEST_PATH_IMAGE011
difference of (2)
Figure 119890DEST_PATH_IMAGE009
If the value is less than the threshold value, the iterative program is ended, and the damping coefficient is output
Figure 126898DEST_PATH_IMAGE010
Is the vertical damping coefficient of the heave plate. Typically, two to three iterations yield an accurate damping coefficient. The iteration times are less, and the vertical damping coefficient of the floating fan heave plate can be quickly determined according to the environmental working condition.
Compared with the prior art, the technical scheme of the invention has the following technical effects:
continuing to refer to fig. 1, the calculation of the damping coefficient is divided into two parts, mainly in the time domain, in addition, the initial damping coefficient is required to be led into the frequency domain for calculation to obtain the hydrodynamic coefficient, and then each hydrodynamic coefficient is led into a time domain calculation program for analog calculation, namely, the influence factors on the damping coefficient in the frequency domain are led into the calculation, so that the accuracy of the calculation result is improved;
extracting the vertical speed time course of the heave plate according to the simulation result of the time domain calculation program
Figure 837365DEST_PATH_IMAGE003
And the vertical velocity time course of the water particles at the heave plate
Figure 643647DEST_PATH_IMAGE004
The relative speed time course of the heave plate is obtained, namely the relative speed time course of the heave plate is introduced into the calculation of the damping coefficient, the influence of the flow velocity of a flow field on the damping coefficient is considered, the damping coefficient can be independently calculated for structures at different flow field positions, and the calculation more conforms to the physical law.
And then calculating the corresponding damping force by using the damping coefficient of each period, performing time integration on the damping force time course to obtain the total damping force energy, and then obtaining the damping coefficient under the whole time course. And finally, judging whether the time domain calculation program is converged, if not, entering an iterative program, and otherwise, directly outputting the damping coefficient. The method is based on potential flow calculation, has high calculation efficiency and fewer iteration times, and can quickly determine the vertical damping coefficient of the floating fan heave plate according to the environmental working condition.
In addition, the method has stronger robustness, namely the estimated dependency of the initial motion under a certain environment working condition is not strong, and even if the estimated initial damping coefficient has larger deviation, the finally obtained damping coefficient still has smaller deviation.
In the foregoing description of embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are also within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. A method for calculating the vertical damping coefficient of a heave plate of a floating structure is characterized by comprising the following steps:
s1, estimating an initial damping coefficient according to environmental conditions
Figure 370462DEST_PATH_IMAGE001
；
S2, according to the initial damping coefficient
Figure 564683DEST_PATH_IMAGE001
Calculating the secondary damping coefficient
Figure 496867DEST_PATH_IMAGE002
While damping the initial dampingCoefficient of performance
Figure 185468DEST_PATH_IMAGE001
Leading the water power coefficient into a frequency domain to calculate the water power coefficient;
s3, calculating the secondary damping coefficient
Figure 152287DEST_PATH_IMAGE002
And guiding the hydrodynamic force coefficient into a time domain calculation program to carry out simulation calculation to obtain the vertical speed time course of the heave plate
Figure 251830DEST_PATH_IMAGE003
And the vertical velocity time course of the water particles at the heave plate
Figure 936889DEST_PATH_IMAGE004
；
S4, calculating the damping coefficient of each period in the time course according to the simulation result in the step S3
Figure 662138DEST_PATH_IMAGE005
And damping force
Figure 483463DEST_PATH_IMAGE006
；
S5, according to the damping force in the step S4
Figure 426011DEST_PATH_IMAGE006
Calculating the damping force energy of the whole time course
Figure 457421DEST_PATH_IMAGE007
And using the energy of the damping force
Figure 612459DEST_PATH_IMAGE007
Calculating the damping coefficient of the whole time course
Figure 163657DEST_PATH_IMAGE008
；
S6, comparing the damping coefficient in the step S5
Figure 745948DEST_PATH_IMAGE008
Comparing the damping coefficient with the initial damping coefficient in the step S1, and if the damping coefficient is different from the initial damping coefficient
Figure 264654DEST_PATH_IMAGE009
If the damping coefficient is less than the threshold value, the damping coefficient is output
Figure 957804DEST_PATH_IMAGE008
The damping coefficient is the vertical damping coefficient of the heave plate, otherwise the damping coefficient is
Figure 862044DEST_PATH_IMAGE008
Enter an iterative procedure to a difference value
Figure 615236DEST_PATH_IMAGE009
Less than the threshold.
2. The method of claim 1, wherein the iteration of step S6 is:
setting the initial damping coefficient in the step S2
Figure 355659DEST_PATH_IMAGE001
Is replaced with the damping coefficient
Figure 852499DEST_PATH_IMAGE008
Repeating the steps S2-S5 to obtain the damping coefficient
Figure 378290DEST_PATH_IMAGE010
Then comparing the damping coefficients
Figure 302383DEST_PATH_IMAGE010
And
Figure 467785DEST_PATH_IMAGE011
when difference is between
Figure 627371DEST_PATH_IMAGE009
When the damping coefficient is less than the threshold value, the damping coefficient is output
Figure 132302DEST_PATH_IMAGE010
Is the vertical damping coefficient of the heave plate.
3. The method for calculating the vertical damping coefficient of a heave plate of a floating structure according to claim 1, wherein the step S1 comprises the following steps:
s11, estimating a motion response zeta of the heave plate in the heave direction according to the environment parameters;
s12, calculating an initial KC value according to the motion response zeta, wherein a calculation formula of the initial KC value is as follows:
Figure 601198DEST_PATH_IMAGE012
；
wherein D is the diameter of the heave plate;
s13, substituting the initial KC value in the step S12 into a formula I to calculate an initial damping coefficient
Figure 191580DEST_PATH_IMAGE001
：
Figure 889277DEST_PATH_IMAGE013
。
4. The method as claimed in claim 1, wherein the second damping coefficient in step S2 is calculated by using the second damping coefficient
Figure 514294DEST_PATH_IMAGE002
The calculation formula of (2) is as follows:
Figure 655556DEST_PATH_IMAGE014
；
wherein the content of the first and second substances,
Figure 733234DEST_PATH_IMAGE015
is the density of seawater.
5. The method as claimed in claim 1, wherein the hydrodynamic coefficient of step S2 comprises wave force
Figure 234622DEST_PATH_IMAGE016
Additional mass
Figure 714145DEST_PATH_IMAGE017
And radiation damping
Figure 524844DEST_PATH_IMAGE018
。
6. The method of claim 5, wherein the wave force is applied to the heave plate of the floating structure
Figure 886555DEST_PATH_IMAGE016
The calculation formula of (2):
Figure 67001DEST_PATH_IMAGE019
；
wherein the content of the first and second substances,
Figure 791243DEST_PATH_IMAGE020
is the incident potential of the light beam, and,
Figure 398942DEST_PATH_IMAGE021
is the diffraction potential of the light beam,
Figure 60998DEST_PATH_IMAGE022
is a vector of a normal vector of a unit,
Figure 779556DEST_PATH_IMAGE023
is the degree of freedom of the object and S is a line infinitesimal.
7. The method as claimed in claim 1, wherein the damping coefficient per cycle of step S4 is calculated by using the damping coefficient per cycle of the heave plate of the floating structure
Figure 358305DEST_PATH_IMAGE005
The calculation process specifically comprises the following steps:
s41, calculating the relative heave velocity time course of the heave plate relative to the water particle according to the simulation result of the step S3
Figure 136905DEST_PATH_IMAGE024
；
S42, selecting the maximum relative heave speed time interval in each period T
Figure 784793DEST_PATH_IMAGE025
Post-calculation KC' value:
Figure 307041DEST_PATH_IMAGE026
；
s43, substituting the KC' value in the step S42 into a formula I to calculate a damping coefficient of each period
Figure 412400DEST_PATH_IMAGE005
：
Figure 689798DEST_PATH_IMAGE027
。
8. The method as claimed in claim 1, wherein the damping force is applied in each period of step S4
Figure 513397DEST_PATH_IMAGE006
The calculation formula of (2) is as follows:
Figure 652386DEST_PATH_IMAGE028
。
9. the method as claimed in claim 1, wherein the step S5 of calculating the damping force energy is performed by using a damping force energy
Figure 877831DEST_PATH_IMAGE007
By damping forces for each period T
Figure 122867DEST_PATH_IMAGE006
And performing time integration to obtain the target.
10. The method as claimed in claim 1, wherein the damping coefficient over the entire time period in step S5 is calculated
Figure 371446DEST_PATH_IMAGE008
The calculation formula of (c) is:
Figure 609398DEST_PATH_IMAGE029
。
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