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1.
本文采用圆柱体阵列来模拟珊瑚礁面的大糙率,通过波浪水槽实验研究礁面糙率对孤立波传播变形及岸滩爬高的影响。结果表明,粗糙礁面的存在显著削弱了礁坪上孤立波的首峰和礁后岸滩反射造成的次峰,同时降低了波浪在珊瑚礁面的传播速度;垂直于岸线方向沿礁相对波高随着入射波增大而减小,随着礁坪水深的增大而增大,粗糙礁面上波高沿礁的衰减更为显著;礁前斜坡的无量纲反射波高随无量纲入射波高的变化与礁坪水深有关,当入射波高足够大时其趋于常值,粗糙礁面略微增大了礁前斜坡的反射;无量纲透射波高和岸滩爬高随着无量纲入射波高的增大而减小,特别是礁坪水深较大时更为显著,粗糙礁面时的无量纲岸滩爬高相对于光滑礁面平均减小46%;通过回归分析得出了同时适合于光滑和粗糙礁面的预测孤立波岸滩爬高的经验关系式。 相似文献
2.
I. I. Didenkulova E. N. Pelinovsky O. I. Didenkulov 《Izvestiya Atmospheric and Oceanic Physics》2014,50(5):532-538
We study the run-up of long solitary waves of different polarities on a beach in the case of composite bottom topography: a plane sloping beach transforms into a region of constant depth. We confirm that nonlinear wave deformation of positive polarity (wave crest) resulting in an increase in the wave steepness leads to a significant increase in the run-up height. It is shown that nonlinear effects are most strongly pronounced for the run-up of a wave with negative polarity (wave trough). In the latter case, the run-up height of such waves increases with their steepness and can exceed the amplitude of the incident wave. 相似文献
3.
The influence of the incident wave form on the extreme (maximal) characteristics of a wave at a beach (run-up and draw-down heights, run-up and draw-down velocities, and the breaking parameter) is studied. It is suggested to use in the calculations the definition of wavelength at a level of 2/3 of the maximal height, which to a certain degree correlates with the definition of the significant wavelength accepted in oceanology. Such a definition allows us to unify the relations for extreme run-up characteristics so that the influence of the incident wave form becomes insignificant. The obtained universal relations can be used for the estimates of run-up characteristics when the exact information about the form of the incident wave is not available. 相似文献
4.
This paper presents new laboratory experiments carried out in a supertank (300 m × 5 m × 5.2 m) of breaking solitary waves evolution on a 1:60 plane beach. The measured data are employed to re-examine existing formulae that include breaking criterion, amplitude evolution and run-up height. The properties of shoreline motion, underwater particle velocity and scale effect on run-up height are briefly discussed. Based on our analyses, it is evidently found that there exist five zones during a wave amplitude evolution course on the present mild slope. A simple formula which is capable of predicting maximum run-up height for a breaking solitary wave on a uniform beach with a wide range of beach slope (1:15–1:60) is also proposed. The calculated results from the present model agree favorably with available laboratory data, indicating that our method is compatible with other predictive models. 相似文献
5.
Extreme value statistics for wave run-up on a natural beach 总被引：1，自引：0，他引：1
R. A. Holman 《Coastal Engineering》1986,9(6)
Statistics of wave run-up maxima have been calculated for 149 35-minutes data runs from a natural beach. During the experiment incident wave height varied from 0.4 to 4.0 m, incident wave period from 6 to 16 s, and beach face slope from 0.07 to 0.20. Four extreme statistics were calculated; the maximum run-up height during each run, the 2% exceedence level of shoreline elevation, the 2% exceedence height for individual run-up peaks, and the 2% exceedence level for swash height as determined by the zero-upcrossing method. These statistics were best parameterized when normalized by the incident significant wave height and plotted against the Iribarren number, ξ = β/(H/L0)1/2. The swash data (with set-up removed) showed less scatter than total run-up (with set-up included). For Iribarren number greater than 1.5 the run-up was dominated by the incident frequencies, for lower Iribarren number longer period motions dominated the swash. A reasonable value of wave steepness for a fully developed storm sea is 0.025 so that a storm Iribarren number can be estimated as 6.3 times the beach slope. Using this and an offshore design wave height, the included graphs may provide guidance in determining a design run-up height. 相似文献
6.
The run-up and back-wash processes of single and double solitary waves on a slope were studied experimentally. Experiments were conducted in three different wave flumes with four different slopes. For single solitary wave, new experimental data were acquired and, based on the theoretical breaking criterion, a new surf parameter specifically for breaking solitary waves was proposed. An equation to estimate maximum fractional run-up height on a given slope was also proposed. For double solitary waves, new experiments were performed by using two successive solitary waves with equal wave heights; these waves were separated by various durations. The run-up heights of the second wave were found to vary with respect to the separation time. Particle image velocimetry measurements revealed that the intensity of the back-wash flow generated by the first wave strongly affected the run-up height of the second wave. Showing trends similar to that of the second wave run-up heights, both the back-wash breaking process of the first wave and the reflected waves were strongly affected by the wave–wave interaction. Empirical run-up formula for the second solitary wave was also introduced. 相似文献
7.
I. I. Didenkulova A. V. Sergeeva E. N. Pelinovsky S. N. Gurbatov 《Izvestiya Atmospheric and Oceanic Physics》2010,46(4):530-532
A run-up of irregular long sea waves on a beach with a constant slope is studied within the framework of the nonlinear shallow-water
theory. This problem was solved earlier for deterministic waves, both periodic and pulse ones, using the approach based on
the Legendre transform. Within this approach, it is possible to get an exact solution for the displacement of a moving shoreline
in the case of irregular-wave run-up as well. It is used to determine statistical moments of run-up characteristics. It is
shown that nonlinearity in a run-up wave does not affect the velocity moments of the shoreline motion but influences the moments
of mobile shoreline displacement. In particular, the randomness of a wave field yields an increase in the average water level
on the shore and decrease in standard deviation. The asymmetry calculated through the third moment is positive and increases
with the amplitude growth. The kurtosis calculated through the fourth moment turns out to be positive at small amplitudes
and negative at large ones. All this points to the advantage of the wave run-up on the shore as compared to a backwash at
least for small-amplitude waves, even if an incident wave is a Gaussian stationary process with a zero mean. The probability
of wave breaking during run-up and the applicability limits for the derived equations are discussed. 相似文献
8.
Wave hydrodynamics over fringing reefs is largely controlled by the reef surface roughness and hydrodynamic forcing. It is believed that climate change will result in a net increase in the water depth over the reef flat, a degrading of the surface roughness of coral reefs and changes in extreme incident wave heights. For an accurate assessment of how climate change affects the safety of reef-fringed coasts, a numerical study of the impact of climate change on irregular wave run-up over reef-fringed coasts was carried out based on a Boussinesq wave model,FUNWAVE-TVD. Validated with experimental data, the present model shows reasonable prediction of irregular wave evolution and run-up height over fringing reefs. Numerical experiments were then implemented based on the anticipated effects of climate change and carried out to investigate the effects of sea level rise, degrading of the reef surface roughness and increase of extreme incident wave height on the irregular wave run-up height over the backreef beach respectively. Variations of run-up components(i.e., spectral characteristics of run-up and mean water level) were examined specifically and discussed to better understand the influencing mechanism of each climate change-related effect on the run-up. 相似文献
9.
Vegetation damping effects on propagating water waves have been investigated by many researchers. This paper investigates the effects of damping due to vegetation on solitary water wave run-up via numerical simulation. The numerical model is based on an implementation of Morison's formulation for vegetation induced inertia and drag stresses in the nonlinear shallow water equations. The numerical model is solved via a finite volume method on a Cartesian cut cell mesh. The accuracy of the numerical scheme and the effects of the vegetation terms in the present model are validated by comparison with experiment results. The model is then applied to simulate a solitary wave propagating on a plane slope with vegetation. The sensitivity of solitary wave run-up to plant height, diameter and stem density is investigated by comparison of the numerical results for different patterns of vegetation. The numerical results show that vegetation can effectively reduce solitary wave propagation velocity and that solitary wave run-up is decreased with increase of plant height in water and also diameter and stem density. 相似文献
10.
Wang Liang
Du Heng Lecturer Hohai University Nanjing Engineer Jiangsu Communication Planning Design Institute Nanjing 《中国海洋工程》1993,(1)
- Engineers in coastal engineering have been paying much attention to the research subject on wave breaking. In this paper, previous research results on the calculating methods of wave breaking depth and height are enumerated, the laws of wave transformation before and after wave breaking are investigated, an adequate supposition is made, and the effect of beach slope, bed friction and breaking turbulence on wave breaking is considered. By applying the theory of wave energy dissipation rate and combining with proper formulas of solitary waves, a new calculating formula of wave breaking depth and height on the movable bed is derived and examined with the data from experimental pools of different sizes, and it is proved to be of practicability. 相似文献
11.
This paper considers the numerical simulation of nonlinear wave run-up within a highly accurate Boussinesq-type model. Moving wet–dry boundary algorithms based on so-called extrapolating boundary techniques are utilized, and a new variant of this approach is proposed in two horizontal dimensions. As validation, computed results involving the nonlinear run-up of periodic as well as transient waves on a sloping beach are considered in a single horizontal dimension, demonstrating excellent agreement with analytical solutions for both the free surface and horizontal velocity. In two horizontal dimensions cases involving long wave resonance in a parabolic basin, solitary wave evolution in a triangular channel, and solitary wave run-up on a circular conical island are considered. In each case the computed results compare well against available analytical solutions or experimental measurements. The ability to accurately simulate a moving wet–dry boundary is of considerable practical importance within coastal engineering, and the extension described in this work significantly improves the nearshore versatility of the present high-order Boussinesq approach. 相似文献
12.
基于非静压单相流模型NHWAVE建立了高精度二维数值波浪水槽,采用日本2011年实测真实海啸波型系统研究了海啸波在岛礁上传播变形的规律,并且分析了波高、礁坪淹没水深和礁前斜坡坡度等因素对孤立波和真实海啸传播变形的影响。结果表明,相比孤立波,类海啸波的波长明显大于孤立波波长,在测点处引起的水面变化持续时间更长,同等波高情况下真实海啸波型比孤立波能够携带更多的能量,与岛礁的相互作用也更为复杂,在礁坪上形成的淹没水深约为孤立波的两倍。礁前斜坡坡度和礁坪淹没水深均对类海啸波的反射和透射系数有显著影响。随着礁前斜坡坡度的增加,反射系数和透射系数均逐渐增加。随着礁坪淹没水深的增加,反射系数逐渐减小,而透射系数逐渐增大。但是,反射系数和透射系数均随着入射波高的增加而逐渐减小。 相似文献
13.
14.
A series of hydraulic model tests has been carried out in a glass wave flume to investigate the influences of wave height, wave period, wave steepness, surf similarity parameter, roughness, layer thickness and porosity on wave run-up and overtopping of 1:2 sloped impermeable and permeable breakwaters fronted by a 1:10 gentle, smooth beach slope. The analysis of results involves the correlation between the overtopping energy transfer with the relative wall height and the relationship between wave run-up and overtopping rate. Further, measured wave run-up and overtopping rates are compared with the results given in the Shore Protection Manual (1984), Automated Coastal Engineering System (1992)and results of other investigators. 相似文献
15.
Benchmark computations of wave run-up on single cylinder and four cylinders by naoe-FOAM-SJTU solver
The benchmark simulations of wave run-up on a fixed single truncated circular cylinder and four circular cylinders are presented in this paper. Our in-house CFD solver naoe-FOAM-SJTU is adopted which is an unsteady two-phase CFD code based on the open source package OpenFOAM. The Navier-Stokes equations are employed as the governing equations, and the volume of fluid (VOF) method is applied for capturing the free surface. Monochromatic incident waves with the specified wave period and wave height are simulated and wave run-up heights around the cylinder are computed and recorded with numerical virtual wave probes. The relationship between the wave run-up heights and the incident wave parameters are analyzed. The numerical results indicate that the presented naoe-FOAM-SJTU solver can provide accurate predictions for the wave run-up on one fixed cylinder and four cylinders, which has been proved by the comparison of simulated results with experimental data. 相似文献
16.
《Coastal Engineering》1999,36(3):219-242
This paper presents numerical simulations and analytical predictions of key aspects of swash oscillations on a steep beach. Simulations of the shoreline displacement based on bore run-up theory are found to give excellent agreement with recent experimental data for regular waves, wave groups and random waves. The theory is used to derive parameters that predict the onset of swash saturation and the spectral characteristics of the saturated shoreline motion. These parameters are again in good agreement with the measured laboratory data and are also consistent with previous experimental data. Simulation of irregular wave run-up using a series of overlapping monochromatic swash events is found to reproduce typical features of swash oscillations and can accurately describe both the low and high frequency spectral characteristics of the swash zone. In particular, the low frequency components of the run-up can be modelled directly using a sequence of incident short wave bores, with no direct long wave input to the numerical simulations. This suggests that wave groupiness must be accounted for when modelling shoreline oscillations. 相似文献
17.
本文通过波浪水槽试验研究了大糙率礁面影响下波浪沿礁的演化和爬高规律,测试了一系列规则波工况并对比了光滑礁面和粗糙礁面的情况。结果分析表明：二次谐波是礁坪上透射波的重要组成成分,粗糙礁面使主频波和二次谐波减小,对更高阶波的影响不显著;相对礁坪水深是描述礁坪上波浪透射的关键参数,礁面从光滑变为粗糙时海岸附近透射系数显著减小,能量衰减系数平均增大了8%,但礁前反射系数与礁面糙率之间无明显关系;礁后岸滩爬高随着透射波高的增大而增长,最后拟合了本文试验条件下珊瑚礁大糙率礁面预测规则波爬高的关系式。 相似文献
18.
为了探究岛屿周围珊瑚礁在抵御海啸灾害中的作用,采用激波捕捉类Boussinesq模型FUNWAVE-TVD,对孤立波在理想化三维岛礁地形上的传播及爬坡开展了现场尺度的平面二维数值模拟,分析了入射波高、礁坪水深、礁坪宽度、礁前斜坡坡度、礁后斜坡坡度、珊瑚礁糙率对岛屿四周孤立波爬高分布的影响。结果表明,珊瑚礁的存在总体上可有效降低岛屿四周孤立波的最大爬坡高度;入射波高、礁坪水深、礁坪宽度、珊瑚礁糙率是影响珊瑚岛礁四周孤立波爬坡分布的主要因素,岛礁四周最大爬坡高度会随入射波高和礁坪水深的增大、礁坪宽度和珊瑚礁糙率的减小而不断增大;当礁坪水深增大到一定程度时,珊瑚礁主要会对岛屿背浪面的爬高失去影响,而当礁坪宽度和珊瑚礁糙率减小至一定程度时,会出现岛礁四周最大爬高高于无珊瑚礁时爬高的现象;礁后斜坡的变缓会使岛礁周围的最大爬高有所减小,而礁前斜坡坡度对珊瑚岛礁周围的最大爬高几乎没有影响。 相似文献
19.
Oceanology - Abstract—The nonlinear problem of run-up of a long wave on a plane beach in presence of a tide is solved within nonlinear shallow water theory using the Carrier–Greenspan... 相似文献
20.
《Coastal Engineering》1988,12(2):175-189
The time series of shoreline variations (run-up variations) due to random waves have been measured on uniform sloping beaches with slopes ranging from to and the energy spectra of the variations (run-up spectra) have been examined. The main characteristics of run-up spectra obtained from the experimental results are as follows: (1) a phenomenon of energy saturation is seen in a high frequency region; and (2) the spectral energy densities are independent of offshore incident wave energy. In the saturation region, the run-up spectra show f−4 dependence and tan 4θ dependence (f: frequency, tanθ: beach slope). Only in a low frequency region, the energy densities increase with increasing incident wave energy. In addition to the experimental study, it is shown by numerical simulations that if run-up variations are formed by parabolas induced by bores running up and down on the beach surface, the spectra of the variations show f−4 dependence, and the low frequency run-up energy densities increase with increasing running-up velocities of bores. 相似文献