Method and device for determining instantaneous sediment transport rate of lower-level sediment preparation under action of waves

Abstract

The invention provides a method and a device for determining the instantaneous sediment transport rate of graded sand under the action of waves. The method comprises the following steps: acquiring sediment settling velocities, exposure hiding factors, phase difference parameters and wave boundary layer thicknesses of different components in graded sand; according to the sediment settling velocity, the exposure hiding factor and the phase difference parameter, the sediment amount of different components in the graded sand is calculated; and calculating the instantaneous sediment transport rate of the graded sand based on the sediment amount of different components in the graded sand and the thickness of the wave boundary layer. According to the method, the instantaneous sediment transport rate of the graded sand is designed and calculated through the obtained sediment settling velocity, the exposure hiding factor, the phase difference parameter, the thickness of the wave boundary layer and other parameters, and the process can reflect the exposure hiding effect between different components in the instantaneous sediment transport rate and the net flow caused by asymmetric development of the wave boundary layer; and the phase drift and phase residue of the instantaneous sediment transport rate relative to the flow velocity can be reflected, and the instantaneous estimation precision of the graded sand is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy engineering, and in particular to a method and a device for determining the instantaneous sediment transport rate of graded sediment under wave action. Background Art

[0002] The periodic reciprocating wave motion makes the sediment movement in the coastal zone have the characteristics of non-constant, non-saturated and unbalanced transport.

[0003] Most of the sediment in nature is graded sand. The exposure and hiding effects between different components in graded sand will affect the transport of sediment along the coast and across the coast.

[0004] The instantaneous sediment transport rate is the amount of sediment flowing through a river section per unit time.

[0005] At present, the instantaneous sediment transport rate widely used in engineering is derived based on the theory of uniform sand steady flow, but it does not take into account the exposure and hiding effects, the asymmetric development of the wave boundary layer, and the phase difference effect. This will make it impossible to calculate the sediment transport rate of different components in the graded sand, and cannot reflect the exposure and hiding effects between different components in the graded sand, the net flow caused by the asymmetric development of the wave boundary layer, and the phase drift and phase residue of the sediment transport rate relative to the flow velocity.

[0006] Therefore, it is very necessary to solve the problem that the existing method for determining instantaneous sediment transport rate does not take into account the exposure and hiding effect, the asymmetric development of the wave boundary layer and the phase difference effect, resulting in low accuracy of the instantaneous sediment transport rate. Summary of the invention

[0007] The present invention provides a method and device for determining the instantaneous sediment transport rate of graded sand under the action of waves, so as to overcome the defect that the instantaneous sediment transport rate obtained by the existing method for determining the instantaneous sediment transport rate is not accurate because the exposure and concealment effects, the asymmetric development of the wave boundary layer and the phase difference effect are not considered. The method can not only reflect the exposure and concealment effects between different components in the instantaneous sediment transport rate and the net flow caused by the asymmetric development of the wave boundary layer, but also reflect the phase drift and phase residue of the instantaneous sediment transport rate relative to the flow velocity, thereby further improving the estimation accuracy of the instantaneous sediment transport rate of the graded sand.

[0008] On the one hand, the present invention provides a method for determining the instantaneous sediment transport rate of graded sand under the action of waves, comprising: obtaining the sediment settling velocity, exposure and hiding factors, phase difference parameters and wave boundary layer thickness of different components in the graded sand; calculating the sediment amount of different components in the graded sand according to the sediment settling velocity, exposure and hiding factors, and phase difference parameters; calculating the instantaneous sediment transport rate of the graded sand based on the sediment amount of different components in the graded sand and the wave boundary layer thickness.

[0009] Furthermore, the instantaneous sediment transport rate of the graded sand is calculated based on the sediment amount of different components in the graded sand and the thickness of the wave boundary layer, including: calculating the instantaneous sediment transport rate of different components in the graded sand according to the sediment amount of different components in the graded sand and the thickness of the wave boundary layer; calculating the instantaneous sediment transport rate of the graded sand under the action of waves according to the instantaneous sediment transport rates of different components in the graded sand.

[0010] Furthermore, the instantaneous sediment transport rate of different components in the graded sand is calculated by the following formula:

[0011]

[0012] Among them, φ i is the instantaneous sediment transport rate of component i in the graded sand, C m is the maximum volume concentration, U is the velocity of the outer boundary layer, Δ i is the sediment content of component i in the graded sand, p i is the proportion of sediment in component i in the graded sand, N is the number of sediment components in the graded sand, δ B is the wave boundary layer thickness.

[0013] Furthermore, the sediment settling velocity is calculated by the following formula:

[0014]

[0015] Among them, σ g is the geometric standard deviation of graded sand, d m is the arithmetic mean particle size of graded sand, d i is the particle size of component i in the graded sand, ν is the kinematic viscosity coefficient of water, s is the ratio of the density of sediment to water, and g is the acceleration of gravity.

[0016] Furthermore, the phase difference parameter is calculated by the following formula:

[0017]

[0018]

[0019] β 2i =3.2-β 1i

[0020] Among them, φ i , β 1i , β 2i is the phase difference parameter of component i in graded sand, σ=2π / T is the frequency, Θ mi is the Sheartz number Θ of component i in graded sand i The maximum value, w i is the sediment settling velocity of component i in graded sand, um is the maximum value of the outer boundary layer velocity u, η i is the exposure and hiding factor of component i in graded sand, d i is the particle size of sediment of component i in the graded sand.

[0021] Furthermore, the wave boundary layer thickness can be calculated by the following formula:

[0022] δ B =0.09A 0.82 k N 0.18

[0023] Where A is the wave orbit amplitude, k N It is the roughness height of the graded sand moving bed.

[0024] Furthermore, the wave track amplitude is calculated by the following formula:

[0025]

[0026] Among them, A ac,at is the wave trajectory amplitude of the onshore acceleration section and the offshore acceleration section, T ac,at is the wave period of the onshore acceleration section and the offshore acceleration section, u c,t is the outer boundary layer velocity at the peak and trough, A dc,dt is the wave trajectory amplitude during the onshore deceleration stage and the offshore deceleration stage, T dc,dt is the wave period of the onshore deceleration section and the offshore deceleration section;

[0027] The roughness height of the graded sand moving bed surface is calculated by the following formula:

[0028]

[0029] Among them, d m is the arithmetic mean particle size of graded sand, f is the wave friction factor, u is the outer boundary layer velocity, s is the ratio of sediment to water density, and g is the gravitational acceleration.

[0030] In a second aspect, the present invention also provides a device for determining the instantaneous sediment transport rate of graded sand under the action of waves, comprising: a data acquisition module for acquiring the sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand; a sediment quantity calculation module for calculating the sediment quantity of different components in the graded sand according to the sediment settling velocity, exposure and concealment factor and phase difference parameter; an instantaneous sediment transport rate calculation module for calculating the instantaneous sediment transport rate of the graded sand based on the sediment quantity of different components in the graded sand and the wave boundary layer thickness.

[0031] In a third aspect, the present invention also provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a method for determining the instantaneous sediment transport rate of graded sand under the action of waves as described in any one of the above-mentioned methods is implemented.

[0032] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a method for determining the instantaneous sediment transport rate of graded sand under the action of waves as described in any one of the above.

[0033] The present invention provides a method for determining the instantaneous sediment transport rate of graded sand under the action of waves, by obtaining the sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand, and calculating the sediment amount of different components in the graded sand according to the sediment settling velocity, exposure and concealment factor and phase difference parameter, and then calculating the instantaneous sediment transport rate of the graded sand based on the sediment amount of different components in the graded sand and the wave boundary layer thickness. The method is designed and calculated by obtaining parameters such as sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness, and the instantaneous sediment transport rate of each component in the graded sand and the total instantaneous sediment transport rate of the graded sand can be calculated. This process can not only reflect the exposure and concealment effect between different components in the instantaneous sediment transport rate, reflect the net flow caused by the asymmetric development of the wave boundary layer, but also reflect the phase drift and phase residue of the instantaneous sediment transport rate relative to the flow velocity, thereby avoiding the wrong estimation of the instantaneous sediment transport rate of the graded sand, and further improving the instantaneous estimation accuracy of the graded sand. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 A schematic flow chart of a method for determining the instantaneous sediment transport rate of graded sand under wave action provided by the present invention;

[0036] Figure 2 A schematic diagram of the change of the Schertz number within a wave period provided by the present invention;

[0037] Figure 3 A schematic diagram of the change of the roughness height of the movable bed surface provided by the present invention within a wave cycle;

[0038] Figure 4 A schematic diagram of the change of the wave track amplitude within the wave period provided by the present invention;

[0039] Figure 5 A schematic diagram of the change of the wave friction factor provided by the present invention within a wave cycle;

[0040] Figure 6 A schematic diagram of the change of the sediment amount of different components in the graded sand provided by the present invention within a wave cycle;

[0041] Figure 7 A schematic diagram of the change of the wave boundary layer thickness within the wave period provided by the present invention;

[0042] Figure 8 A schematic diagram of the instantaneous sediment transport rate of different components in the graded sand provided by the present invention and the change of the instantaneous sediment transport rate of the graded sand within a wave cycle;

[0043] Fig. 9 A schematic diagram of the changes in the sediment amount and instantaneous sediment transport rate of different components in the graded sand with the exposure and concealment effect removed provided by the present invention within a wave cycle;

[0044] Fig.10 A schematic diagram of the structure of a device for determining the instantaneous sediment transport rate of graded sand under the action of waves provided by the present invention;

[0045] Fig.11 This is a schematic structural diagram of an electronic device provided by the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] It should be noted that the instantaneous sediment transport rates widely used in current engineering are derived based on the theory of uniform sand steady flow, but they do not take into account the exposure and hiding effects, the asymmetric development of the wave boundary layer, and the phase difference effect.

[0048] That is to say, the instantaneous sediment transport rate of graded sand calculated by the existing technology cannot reflect the exposure and hiding effects between different components in the graded sand, cannot reflect the net flow caused by the asymmetric development of the wave boundary layer, and cannot reflect the phase drift and phase residue of the sediment transport rate relative to the flow velocity.

[0049] In view of this, the present invention provides a method for determining the instantaneous sediment transport rate of graded sand under wave action, specifically, Figure 1 The schematic diagram shows the flow chart of the method for determining the instantaneous sediment transport rate of graded sand under the action of waves provided by the present invention.

[0050] like Figure 1 As shown, the method includes:

[0051] S110, obtaining sediment settling velocity, exposure and hiding factor, phase difference parameter and wave boundary layer thickness of different components in graded sand.

[0052] It can be understood that in this embodiment, in order to calculate the instantaneous sediment transport rate of graded sand under the action of waves, it is necessary to first execute step S110, that is, to obtain the sediment settling velocity, exposure and hiding factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand.

[0053] By obtaining the sediment settling velocity and exposure-hiding factor of different components in graded sand, the exposure-hiding effect is taken into consideration when calculating the instantaneous sediment transport rate of graded sand. As a result, the instantaneous sediment transport rate of graded sand calculated subsequently can reflect the mutual influence between different components, reflecting the promoting effect of fine components on coarse components, and the inhibiting effect of coarse components on fine components.

[0054] By obtaining the phase difference parameters of different components in graded sand, the phase difference is taken into consideration when calculating the instantaneous sediment transport rate of graded sand, so that the instantaneous sediment transport rate of graded sand calculated subsequently can reflect the phase drift and phase residual of the instantaneous sediment transport rate relative to the flow velocity.

[0055] At the same time, by obtaining the thickness of the wave boundary layer, the asymmetric development of the wave boundary layer is taken into consideration when calculating the instantaneous sediment transport rate of graded sand, so that the instantaneous sediment transport rate of graded sand calculated subsequently can reflect the net flow caused by the asymmetric development of the wave boundary layer.

[0056] Among them, the process of obtaining the sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand will be further expanded in the subsequent embodiments and will not be described in detail here.

[0057] S120, calculating the sediment amount of different components in the graded sand according to sediment settling velocity, exposure and concealment factor, and phase difference parameter;

[0058] S130, calculating the instantaneous sediment transport rate of the graded sand based on the sediment amounts of different components in the graded sand and the thickness of the wave boundary layer.

[0059] It can be understood that, based on the sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand obtained in step S110, step S120 can further calculate the sediment amount of different components in the graded sand according to a part of the parameters obtained in step S110, namely, the sediment settling velocity, exposure and concealment factor and phase difference parameter.

[0060] The process of calculating the sediment amounts of different components in graded sand will be described in subsequent embodiments and will not be described in detail here.

[0061] Next, step S130 calculates the instantaneous sediment transport rate of the graded sand under the action of waves based on the sediment amounts of different components in the graded sand calculated in step S120 and the wave boundary layer thickness obtained in step S110.

[0062] Specifically, first, the instantaneous sediment transport rates corresponding to different components in the graded sand are calculated according to the sediment amounts of different components in the graded sand and the obtained wave boundary layer thickness. Then, based on the instantaneous sediment transport rates of different components in the graded sand, the total instantaneous sediment transport rate of the graded sand under the action of waves is calculated.

[0063] Among them, the calculation process of the instantaneous sediment transport rate of graded sand will be expanded in subsequent embodiments and will not be described in detail here.

[0064] It should be noted that the method for determining the instantaneous sediment transport rate of graded sand under wave action provided in this embodiment is applied to conditions where graded sand exists near the shore, and is particularly suitable for application scenarios such as beach protection and shoreline reconstruction of graded sand coasts.

[0065] It should also be noted that the method for determining the instantaneous sediment transport rate of graded sand under wave action provided in this embodiment can assist in determining the vertical sediment exchange intensity in related issues such as nearshore sediment transport and beach evolution, and accurately reflect the vertical sediment exchange of different sand layers (such as free sand-containing layers, sand storage layers, and immobile sand-containing layers).

[0066] In this embodiment, the sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand are obtained, and the sediment amount of different components in the graded sand is calculated according to the sediment settling velocity, exposure and concealment factor and phase difference parameter, and then the instantaneous sediment transport rate of the graded sand is calculated based on the sediment amount of different components in the graded sand and the wave boundary layer thickness. This method is designed and calculated by obtaining parameters such as sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness, and can calculate the instantaneous sediment transport rate of each component in the graded sand and the total instantaneous sediment transport rate of the graded sand. This process can not only reflect the exposure and concealment effect between different components in the instantaneous sediment transport rate, reflect the net flow caused by the asymmetric development of the wave boundary layer, but also reflect the phase drift and phase residue of the instantaneous sediment transport rate relative to the flow velocity, avoiding the wrong estimation of the instantaneous sediment transport rate of the graded sand, and further improving the instantaneous estimation accuracy of the graded sand.

[0067] On the basis of the above-mentioned embodiment, the sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand are further obtained. This embodiment will expand the calculation process of this series of parameters.

[0068] For example, in a specific embodiment, the sediment settling velocity of different components in the graded sand is obtained, specifically, the sediment settling velocity w i It can be calculated by the following formula:

[0069]

[0070] Among them, σ g is the geometric standard deviation of graded sand, d m is the arithmetic mean particle size of graded sand, d i is the particle size of component i in the graded sand, ν is the kinematic viscosity coefficient of water, s is the ratio of the density of sediment to water, and g is the acceleration of gravity.

[0071] For example, in another specific embodiment, the exposure hidden factors of different components in the graded sand are obtained, specifically, the exposure hidden factor η i It can be calculated by the following formula:

[0072]

[0073] Among them, η i is the interaction factor of component i in the graded sand, N is the number of sediment components in the graded sand, p j is the proportion of sediment in component j in graded sand, d i is the particle size of component i in the graded sand, d j The sediment particle size of component j in the graded sand, i and j are two different components in the graded sand.

[0074] For example, in another specific embodiment, the phase difference parameters of different components in the graded sand are obtained. Specifically, the phase difference parameters can be calculated by the following formula:

[0075]

[0076]

[0077] β 2i =3.2-β 1i (5)

[0078] Among them, φ i , β 1i , β 2i is the phase difference parameter of component i in graded sand, σ=2π / T is the frequency, Θ miis the Sheartz number Θ of component i in graded sand i The maximum value, w i is the sediment settling velocity of component i in graded sand, u m is the maximum value of the outer boundary layer velocity u, η i is the exposure and hiding factor of component i in graded sand, d i is the particle size of sediment of component i in the graded sand.

[0079] Among them, w i and η i They can be calculated by the above formulas (1) and (2) respectively.

[0080] In formula (3), θ mi is the Sheartz number Θ of component i in graded sand i The maximum value of the Scherz number Θ i It can be calculated by the following formula:

[0081]

[0082] Among them, f is the wave friction factor, u is the outer boundary layer velocity, s is the ratio of sediment to water density, and g is the gravitational acceleration.

[0083] In formula (6), the wave friction factor can be calculated by the following formula:

[0084]

[0085] Among them, A ac,at is the wave trajectory amplitude of the onshore acceleration section and the offshore acceleration section, T ac,at is the wave period of the onshore acceleration section and the offshore acceleration section, k N is the roughness height of the graded sand moving bed, T c,t is the wave period at the peak and trough, f ac,at is the wave friction factor in the onshore acceleration section and the offshore acceleration section, A dc,dt is the wave trajectory amplitude during the onshore deceleration stage and the offshore deceleration stage, T dc,dt is the wave period of the onshore deceleration section and the offshore deceleration section, f dc,dt is the wave friction factor in the onshore deceleration section and the offshore deceleration section.

[0086] According to formula (7), the subscripts c and t represent the peak and trough moments; the subscripts ac, at, dc and dt represent the onshore acceleration segment, the offshore acceleration segment, the onshore deceleration segment and the offshore deceleration segment.

[0087] In formula (7), the wave track amplitude A ac,at , A dc,dt It can be calculated by the following formula:

[0088]

[0089] Among them, u c,t is the outer boundary layer velocity at the peak and trough moments.

[0090] Roughness height k of graded sand moving bed N It can be obtained by the following calculation formula:

[0091]

[0092] For another example, in another specific embodiment, the wave boundary layer thickness is obtained, specifically, the wave boundary layer thickness δ B It can be calculated by the following formula:

[0093] δ B =0.09A 0.82 k N 0.18 (10)

[0094] Where A is the orbital amplitude of the wave, k N It is the roughness height of the graded sand moving bed.

[0095] A and K N They can be calculated by the above formulas (8) and (9) respectively.

[0096] According to the above formulas (1)-(10), the sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand can be calculated. Furthermore, the sediment amount of different components in the graded sand can be calculated according to the sediment settling velocity, exposure and concealment factor and phase difference parameter. Therefore, based on the sediment amount of different components in the graded sand and the wave boundary layer thickness, the instantaneous sediment transport rate of the graded sand can be calculated.

[0097] In this embodiment, the sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand are obtained, and the sediment amount of different components in the graded sand is calculated according to the sediment settling velocity, exposure and concealment factor and phase difference parameter, and then the instantaneous sediment transport rate of the graded sand is calculated based on the sediment amount of different components in the graded sand and the wave boundary layer thickness. This method is designed and calculated by obtaining parameters such as sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness, and can calculate the instantaneous sediment transport rate of each component in the graded sand and the total instantaneous sediment transport rate of the graded sand. This process can not only reflect the exposure and concealment effect between different components in the instantaneous sediment transport rate, reflect the net flow caused by the asymmetric development of the wave boundary layer, but also reflect the phase drift and phase residue of the instantaneous sediment transport rate relative to the flow velocity, avoiding the wrong estimation of the instantaneous sediment transport rate of the graded sand, and further improving the instantaneous estimation accuracy of the graded sand.

[0098] On the basis of the above embodiments, further, according to the sediment settling velocity, exposure hiding factor and phase difference parameter of different components in the graded sand, the sediment amount of different components in the graded sand is calculated, and based on the sediment amount of different components in the graded sand and the thickness of the wave boundary layer, the instantaneous sediment transport rate of the graded sand is calculated.

[0099] Specifically, the amount of sediment corresponding to different components in graded sand is Δ i It can be calculated by the following formula:

[0100]

[0101] Among them, σ = 2π / T is the frequency, t is the time, φ i , β 1i , β 2i is the phase difference parameter of component i in graded sand, Θ i is the Sheartz number of component i in graded sand, Θ mi is the Sheartz number Θ of component i in graded sand i The maximum value of u m is the maximum value of the outer boundary layer velocity u, w i is the sediment settling velocity of the graded sand components, η i is the exposure and hiding factor of component i in graded sand, d i is the particle size of sediment of component i in the graded sand.

[0102] Calculate the sediment volume Δ corresponding to different components in the graded sand i Afterwards, according to the sediment volume Δ corresponding to different components in the graded sand i and wave boundary layer thickness, and calculate the instantaneous sediment transport rate of different components in the graded sand.

[0103] It should be emphasized here that, in a specific embodiment, according to the sediment amount Δ corresponding to different components in the graded sand i and wave boundary layer thickness, before calculating the instantaneous sediment transport rate of different components in the graded sand, in order to more accurately reflect the vertical exchange of sediment among the free sand-bearing layer, sand storage layer and immovable sand-bearing layer, the moving bed surface of the graded sand was divided into free sand-bearing layer, sand storage layer and immovable sand-bearing layer.

[0104] For the free sand layer, it satisfies z>-Δ; for the sand storage layer, it satisfies -max(Δ i )<z≤-Δ; For the immovable sandy layer, it satisfies z≤-max(Δ i ).

[0105] Among them, Δ i is the sediment content of component i in the graded sand, Δ is the erosion depth of the graded sand moving bed, max(Δi ) for all Δ i The maximum value in .

[0106] It should also be noted that the graded sand transport rate only exists in the free sand-bearing layer, but its movement can cross the free sand-bearing layer to reach the sand storage layer.

[0107] Since different components in graded sand move in different forms in different sand layers, the calculation formula for the instantaneous sand transport rate of different components in graded sand is a piecewise function.

[0108] Specifically, the instantaneous sediment transport rate of different components in the graded sand is φ i The preliminary calculation formula is as follows:

[0109]

[0110] Among them, C m is the maximum volume concentration, which is 0.6 in this embodiment, U is the velocity of the outer boundary layer, N is the number of sediment components in the graded sand, and p i is the proportion of sediment in component i in the graded sand, Δ i is the amount of sediment corresponding to component i in the graded sand, δ B is the thickness of the wave boundary layer, α is the phase advance parameter of the moving bed surface velocity and shear stress relative to the outer boundary layer velocity, and V is the kinematic viscosity coefficient of water.

[0111] In formula (12), U and V can be calculated by the following formulas:

[0112]

[0113]

[0114] Among them, U 0 is the velocity amplitude of the outer boundary layer, r is the nonlinear index, σ=2π / T is the frequency, t is the time, t 0 The parameters that make u(0) = 0, is the waveform parameter.

[0115] Because U 0 , r, t 0 as well as are all known values. α is generally ignored when calculating the instantaneous sediment transport rate in engineering. Therefore, formula (12) used to calculate the instantaneous sediment transport rate of different components in graded sand can be simplified to the following formula:

[0116]

[0117] Among them, φ i is the instantaneous sediment transport rate of component i in the graded sand, C mis the maximum volume concentration, U is the velocity of the outer boundary layer, Δ i is the sediment content of component i in the graded sand, p i is the proportion of sediment in component i in the graded sand, N is the number of sediment components in the graded sand, δ B is the wave boundary layer thickness.

[0118] After calculating the instantaneous sediment transport rates of different components in the graded sand, the instantaneous sediment transport rate φ of the graded sand under the action of waves can be calculated according to the instantaneous sediment transport rates of different components in the graded sand. Specifically, it can be calculated by the following formula:

[0119]

[0120] In this embodiment, the instantaneous sediment transport rate of different components in the graded sand is calculated according to the sediment amount of different components in the graded sand and the thickness of the wave boundary layer, and then the instantaneous sediment transport rate of the graded sand under the action of waves is calculated according to the instantaneous sediment transport rate of different components in the graded sand. This method is designed and calculated by obtaining parameters such as sediment settling velocity, exposure and concealment factor, phase difference parameter, and wave boundary layer thickness, and can calculate the instantaneous sediment transport rate of each component in the graded sand and the total instantaneous sediment transport rate of the graded sand. This process can not only reflect the exposure and concealment effect between different components in the instantaneous sediment transport rate, reflect the net flow caused by the asymmetric development of the wave boundary layer, but also reflect the phase drift and phase residue of the instantaneous sediment transport rate relative to the flow velocity, avoid the wrong estimation of the instantaneous sediment transport rate of the graded sand, and further improve the estimation accuracy of the instantaneous sediment transport rate of the graded sand.

[0121] In addition, in a specific embodiment, an application example of a method for determining the sediment transport rate of graded sand under wave action is provided.

[0122] Expanded, given a standard atmospheric pressure, 20℃ water temperature, T = 5s, N = 2, d 1 =0.15mm,d 2 =0.51mm, p 1 =0.5, p 2 =0.5,d m =0.33mm,σ g =2.29, s=2.65, g=9.8m / s2, ν=1.0*10-6m2 / s, using the second-order Strokes reciprocating flow velocity, that is, u(t)=1.2cos[2π(t / T-0.214)]+0.3cos[4π(t / T-0.214)].

[0123] First, calculate d 1 and d 2 The corresponding sediment settling velocity w i and expose the hidden factor η i .

[0124] Specifically, according to the above formula (1), w can be calculated as 1 =0.018m / s, w 2 =0.059m / s; According to the above formula (2), η can be calculated 1 =0.71,η 2 =1.40.

[0125] Then, calculate the wave track amplitude A and the roughness k of the moving bed surface N d 1 and d 2 The corresponding Scherz number Θ i and the wave friction factor f.

[0126] Specifically, according to the above formulas (6)-(9), we can know f, θ i , A and k N The calculation result of .

[0127] Expanded, Figure 2 A schematic diagram showing the change of the Schertz number provided by the present invention within a wave period is shown; Figure 3 A schematic diagram showing the variation of the roughness height of the moving bed surface provided by the present invention (i.e., the roughness height of the graded sand moving bed surface described above) within a wave cycle; Figure 4 A schematic diagram showing the variation of the wave track amplitude provided by the present invention within a wave period is shown; Figure 5 A schematic diagram showing the variation of the wave friction factor provided by the present invention within a wave period is shown.

[0128] exist Figure 2-5 In this case, t / T is the dimensionless time, Θ 1 and θ 2 They are d 1 and d 2 The corresponding Scherz number.

[0129] Then, calculate d 1 and d 2 The corresponding phase difference parameter φ i , β 1i and β 2i .

[0130] Specifically, according to the above formula (3), φ can be calculated 1 =0.51,φ 2 =0.20; According to the above formula (4), β can be calculated 11 =2.16, β 12 =1.17; According to the above formula (5), β can be calculated 21 =1.04,β 22=2.03.

[0131] Next, calculate d 1 and d 2 The corresponding sediment volume Δ i and the wave boundary layer thickness δ B .

[0132] Specifically, according to the above formulas (10)-(11), corresponding calculation results can be obtained.

[0133] Expanded, Figure 6 A schematic diagram showing the change of the sediment amount of different components in the graded sand provided by the present invention during a wave cycle is shown, and Figure 7 A schematic diagram showing the variation of the wave boundary layer thickness provided by the present invention within a wave period is shown.

[0134] exist Figure 6-7 In this case, t / T is the dimensionless time, Δ 1 and Δ 2 They are d 1 and d 2 The corresponding amount of sediment.

[0135] Finally, calculate d 1 and d 2 The corresponding instantaneous sediment transport rate φ i , and the instantaneous sediment transport rate φ of graded sand.

[0136] Specifically, according to the above formulas (15)-(16), the corresponding calculation results can be obtained.

[0137] Expanded, Figure 8 A schematic diagram showing the instantaneous sediment transport rates of different components in the graded sand provided by the present invention and the change of the instantaneous sediment transport rate of the graded sand within a wave cycle is shown.

[0138] exist Figure 8 In, φ 1 and φ 2 They are d 1 and d 2 The corresponding instantaneous sediment transport rate.

[0139] in addition, Fig. 9 Also shown is a schematic diagram of the changes in the sediment amounts and instantaneous sediment transport rates of different components in the graded sand provided by the present invention with the exposure and concealment effects removed within a wave cycle.

[0140] It should be emphasized that, by adopting the method for determining the instantaneous sediment transport rate of graded sand under wave action provided by the present invention, the sediment transport rate of graded sand fully considers the exposure and concealment effect, the asymmetric development of the wave boundary layer and the phase difference effect.

[0141] Compared with the existing method for determining the instantaneous sediment transport rate of graded sand, the present invention has the following advantages:

[0142] On the one hand, the present invention is able to calculate the instantaneous sediment transport rate of different components in graded sand.

[0143] That is, the present invention can accurately calculate the size and direction of net sand transport of different particle sizes of graded sand coast under the action of waves by respectively calculating the instantaneous sand transport rate of each component in the graded sand and the instantaneous sand transport rate of the graded sand.

[0144] On the other hand, the present invention can reflect the interaction of different components in graded sand.

[0145] That is, the present invention takes into account the exposure and concealment effect by calculating the sediment amounts of different components in graded sand, and can reflect the promoting effect of fine components on the movement of coarse components and the inhibiting effect of coarse components on the movement of fine components.

[0146] By comparison Figure 6 , Figure 8 and Fig. 9 It can be seen that under the influence of the exposure and hiding effect, the amount of moving sediment in the fine component decreases, while the amount of moving sediment in the coarse component increases, which further leads to the instantaneous sediment transport rates of the two being very close, and at the peak moment, the sediment amount and instantaneous sediment transport rate of the coarse component will be larger than those of the fine component.

[0147] In addition, the present invention can also reflect the asymmetric development and phase difference effect of the wave boundary layer.

[0148] The present invention takes into account the asymmetric development of the boundary layer by calculating the thickness of the wave boundary layer, thereby being able to reflect the net flow caused by the asymmetric development of the wave boundary layer. At the same time, by calculating the phase difference parameter, the phase drift and phase residue of the instantaneous sediment transport rate relative to the flow velocity are reflected.

[0149] Fig.10 The schematic diagram of the structure of the device for determining the instantaneous sediment transport rate of graded sand under the action of waves provided by the present invention is shown.

[0150] like Fig.10 As shown, the device includes: a data acquisition module 1010, which is used to obtain the sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand; a sediment amount calculation module 1020, which is used to calculate the sediment amount of different components in the graded sand according to the sediment settling velocity, exposure and concealment factor, and phase difference parameter; an instantaneous sediment transport rate calculation module 1030, which is used to calculate the instantaneous sediment transport rate of the graded sand based on the sediment amount of different components in the graded sand and the wave boundary layer thickness.

[0151] In this embodiment, the sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand are obtained by the data acquisition module 1010, and the sediment amount calculation module 1020 calculates the sediment amount of different components in the graded sand according to the sediment settling velocity, exposure and concealment factor and phase difference parameter, and then the instantaneous sediment transport rate calculation module 1030 calculates the instantaneous sediment transport rate of the graded sand based on the sediment amount of different components in the graded sand and the wave boundary layer thickness. The device is designed and calculated by obtaining parameters such as sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness, and can calculate the instantaneous sediment transport rate of each component in the graded sand and the total instantaneous sediment transport rate of the graded sand. This process can not only reflect the exposure and concealment effect between different components in the instantaneous sediment transport rate, reflect the net flow caused by the asymmetric development of the wave boundary layer, but also reflect the phase drift and phase residue of the instantaneous sediment transport rate relative to the flow velocity, avoid the wrong estimation of the instantaneous sediment transport rate of the graded sand, and further improve the instantaneous estimation accuracy of the graded sand.

[0152] It should be noted that the device for determining the instantaneous sediment transport rate of graded sand under the action of waves provided in this embodiment and the method for determining the instantaneous sediment transport rate of graded sand under the action of waves described above can correspond to each other and will not be repeated here.

[0153] Fig.11 An example of a physical structure diagram of an electronic device is shown in FIG. Fig.11 As shown, the electronic device may include: a processor 1110, a communication interface 1120, a memory 1130 and a communication bus 1140, wherein the processor 1110, the communication interface 1120 and the memory 1130 communicate with each other through the communication bus 1140. The processor 1110 may call the logic instructions in the memory 1130 to execute a method for determining the instantaneous sediment transport rate of graded sand under the action of waves, the method comprising: obtaining sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand; calculating the sediment amount of different components in the graded sand according to the sediment settling velocity, exposure and concealment factor and phase difference parameter; calculating the instantaneous sediment transport rate of the graded sand based on the sediment amount of different components in the graded sand and the wave boundary layer thickness.

[0154] In addition, the logic instructions in the above-mentioned memory 1130 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0155] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the method for determining the instantaneous sediment transport rate of graded sand under the action of waves provided by the above-mentioned methods, the method comprising: obtaining the sediment settling velocity, exposure and hiding factor, phase difference parameter and wave boundary layer thickness of different components in the graded sand; calculating the sediment amount of different components in the graded sand according to the sediment settling velocity, exposure and hiding factor and phase difference parameter; calculating the instantaneous sediment transport rate of the graded sand based on the sediment amount of different components in the graded sand and the wave boundary layer thickness.

[0156] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Those of ordinary skill in the art may understand and implement it without creative effort.

[0157] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the instantaneous sediment transport rate of graded sand under wave action, characterized in that: include: Obtain sediment settling velocity, exposure and hiding factors, phase difference parameters and wave boundary layer thickness of different components in graded sand; Calculate the sediment amounts of different components in the graded sand according to the sediment settling velocity, exposure and concealment factor, and phase difference parameter; Based on the sediment amounts of different components in the graded sand and the thickness of the wave boundary layer, the instantaneous sediment transport rate of the graded sand is calculated.

2. The method for determining the instantaneous sediment transport rate of graded sand under wave action according to claim 1, characterized in that: The step of calculating the instantaneous sediment transport rate of the graded sand based on the sediment amounts of different components in the graded sand and the thickness of the wave boundary layer comprises: Calculating the instantaneous sediment transport rate of different components in the graded sand according to the sediment amount of different components in the graded sand and the thickness of the wave boundary layer; According to the instantaneous sediment transport rates of different components in the graded sand, the instantaneous sediment transport rate of the graded sand under the action of waves is calculated.

3. The method for determining the instantaneous sediment transport rate of graded sand under wave action according to claim 2, characterized in that: The instantaneous sediment transport rate of different components in the graded sand is calculated by the following formula: Among them, φ i is the instantaneous sediment transport rate of component i in the graded sand, C m is the maximum volume concentration, U is the velocity of the outer boundary layer, Δ i is the sediment content of component i in the graded sand, p i is the proportion of sediment in component i in the graded sand, N is the number of sediment components in the graded sand, δ B is the wave boundary layer thickness.

4. The method for determining the instantaneous sediment transport rate of graded sand under wave action according to claim 1, characterized in that: The sediment settling velocity is calculated by the following formula: Among them, σ g is the geometric standard deviation of graded sand, d m is the arithmetic mean particle size of graded sand, d i is the particle size of component i in the graded sand, ν is the kinematic viscosity coefficient of water, s is the ratio of the density of sediment to water, and g is the acceleration of gravity.

5. The method for determining the instantaneous sediment transport rate of graded sand under wave action according to claim 1, characterized in that: The phase difference parameter is calculated by the following formula: β 2i ＝3.2-β 1i Among them, φ i , β 1i , β 2i is the phase difference parameter of component i in graded sand, σ=2π / T is the frequency, Θ mi is the Sheartz number Θ of component i in graded sand i The maximum value, w i is the sediment settling velocity of component i in graded sand, u m is the maximum value of the outer boundary layer velocity u, η i is the exposure and hiding factor of component i in graded sand, d i is the particle size of sediment of component i in the graded sand.

6. The method for determining the instantaneous sediment transport rate of graded sand under wave action according to claim 1, characterized in that: The wave boundary layer thickness can be calculated by the following formula: d B =0.09A 0.82 k N 0.18 Among them, A is the wave orbit amplitude, k N It is the roughness height of the graded sand moving bed.

7. The method for determining the instantaneous sediment transport rate of graded sand under wave action according to claim 6, characterized in that: The wave track amplitude is calculated by the following formula: Among them, A ac,at is the wave trajectory amplitude of the onshore acceleration section and the offshore acceleration section, T ac,at is the wave period of the onshore acceleration section and the offshore acceleration section, u c,t is the outer boundary layer velocity at the peak and trough, A dc,dt is the wave trajectory amplitude during the onshore deceleration stage and the offshore deceleration stage, T dc,dt is the wave period of the onshore deceleration section and the offshore deceleration section; The roughness height of the graded sand moving bed surface is calculated by the following formula: Among them, d m is the arithmetic mean particle size of graded sand, f is the wave friction factor, u is the outer boundary layer velocity, s is the ratio of sediment to water density, and g is the gravitational acceleration.

8. A device for determining the instantaneous sediment transport rate of graded sand under wave action, characterized in that: include: Data acquisition module, used to obtain sediment settling velocity, exposure and concealment factor, phase difference parameter and wave boundary layer thickness of different components in graded sand; A sediment volume calculation module is used to calculate the sediment volume of different components in the graded sand according to the sediment settling velocity, exposure and concealment factor, and phase difference parameter; The instantaneous sediment transport rate calculation module is used to calculate the instantaneous sediment transport rate of the graded sand based on the sediment amounts of different components in the graded sand and the thickness of the wave boundary layer.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method for determining the instantaneous sediment transport rate of graded sand under the action of waves as described in any one of claims 1 to 7 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for determining the instantaneous sediment transport rate of graded sand under the action of waves as described in any one of claims 1 to 7 is implemented.

Images