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1.
Reconstructing tsunami run-up from the characteristics of tsunami deposits on the Thai Andaman Coast
Tsunamis can leave deposits on the land surface they inundate. The characteristics of tsunami deposits can be used to calculate tsunami run-up height and velocity. This paper presents a reconstruction of tsunami run-up from tsunami deposit characteristics in a simple mathematical model. The model is modified and applied to reconstruct tsunami run-ups at Ao Kheuy beach and Khuk Khak beach, Phangnga province, Thailand. The input parameters are grain-size and maximum run-up distance of the sediment. The reconstructed run-up heights are 4.16–4.91 m at Ao Kheuy beach and 5.43–9.46 m at Khuk Khak beach. The estimated run-up velocities (maximum velocity) at the still water level are 12.78–19.21 m/s. In the area located 70–140 m inland to the end of run-up inundation, estimated mean run-up velocities decrease from approximately 1.93 m/s to 0 m/s. Reasonably good agreements are found between reconstructed and observed run-up heights. The tsunami run-up height and velocity can be used for risk assessment and coastal development programs in the tsunami affected area. The results show that the area from 0 to 140 m inland was flooded by high velocity run-ups and those run-up energies were dissipated mainly in this area. The area should be designated as either an area where settlement is not permitted or an area where effective protection is provided, for example with flood barriers or forest. 相似文献
2.
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
3.
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
4.
Measuring run-up on a natural beach 总被引：1，自引：0，他引：1
Field experiments have been performed to evaluate and intercompare two techniques for measuring run-up on natural beaches, resistance wires and films. Simultaneous deployment of wire sensors shows a low error (< 5%) in electronics gain, but a strong sensitivity to the elevation of the wires above the beach face. On a low slope (β ～ 0.02) beach, with incident wind waves of moderate height (H ～ 1 m), differences of only a few cm in the wire elevation cause variance differences as large as 25%, in otherwise identical sensors. Replicate digitizations of the same run-up film show variance differences as large as 20%, with an average deviation from the mean variance of 8%.Use of the film and resistance wire sensors on the same run-up field showed small differences in the mean swash elevation (i.e., set-up), but an 83% difference in swash variance. Much further work is needed to determine the dependence of sensor differences on beach slope, porosity, camera elevation and other factors. 相似文献
5.
Reliable estimation of wave run-up is required for the effective and efficient design of coastal structures when flooding or wave overtopping volumes are an important consideration in the design process. In this study, a unified formula for the wave run-up on bermed structures has been developed using collected and existing data. As data on berm breakwaters was highly limited, physical model tests were conducted and the run-up was measured. Conventional governing parameters and influencing factors were then used to predict the dimensionless run-up level with 2% exceedance probability. The developed formula includes the effect of water depth which is required in understanding the influence of sea level rise and consequent changes of wave height to water depth ratio on the future hydraulic performance of the structures. The accuracy measures such as RMSE and Bias indicated that the developed formula is more accurate than the existing formulas. Additionally, the new formula was validated using field measurements and its superiority was observed when compared to the existing prediction formulas. Finally, the new design formula incorporating the partial safety factor was introduced as a design tool for engineers. 相似文献
6.
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
7.
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
8.
《中国海洋工程》2021,(4)
This study numerically and experimentally investigates the effects of wave loads on a monopile-type offshore wind turbine placed on a 1: 25 slope at different water depths as well as the effect of choosing different turbulence models on the efficiency of the numerical model. The numerical model adopts a two-phase flow by solving Unsteady Reynolds-Averaged Navier-Stokes(URANS) equations using the Volume Of Fluid(VOF) method and three different turbulence models. Typical environmental conditions from the East China Sea are studied. The wave run-up and the wave loads applied on the monopile are investigated and compared with relevant experimental data as well as with mathematical predictions based on relevant theories. The numerical model is well validated against the experimental data at model scale. The use of different turbulence models results in different predictions on the wave height but less differences on the wave period. The baseline turbulence model and Shear-Stress Transport(SST) turbulence model exhibit better performance on the prediction of hydrodynamic load, at a model-scale water depth of 0.42 m, while the laminar model provides better results for large water depths. The SST turbulence model performs better in predicting wave run-up for water depth 0.42 m, while the laminar model and standard model perform better at water depth 0.52 m and 0.62 m, respectively. 相似文献
9.
S. F. Dotsenko 《Physical Oceanography》2000,10(6):485-493
We perform the numerical analysis of the intensification of tsunami waves in the course of their propagation from the open
part of the Black Sea to the shelf zone. For this purpose, we use a one-dimensional model of nonlinear long waves taking into
account the effect of bottom friction. We study four profiles of the bottom corresponding to the south coast of the Crimean
Peninsula and establish the predominant role of the bottom pattern and insignificant contribution of nonlinearity to the transformation
of waves in the process of their propagation in the direction of the coast. Down to depths of 50 m, all changes in the height
of waves are described by the Green law. For the evaluation of vertical run-up of waves, it is important to take into account
nonlinear effects. The highest vertical run-ups of waves are observed in the parts of the shelf zone located near Yalta and
Alushta.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
10.
The ∼8.15 ka Storegga submarine slide was a large (∼3000 km3), tsunamigenic slide off the coast of Norway. The resulting tsunami had run-up heights of around 10–20 m on the Norwegian coast, over 12 m in Shetland, 3–6 m on the Scottish mainland coast and reached as far as Greenland. Accurate numerical simulations of Storegga require high spatial resolution near the coasts, particularly near tsunami run-up observations, and also in the slide region. However, as the computational domain must span the whole of the Norwegian-Greenland sea, employing uniformly high spatial resolution is computationally prohibitive. To overcome this problem, we present a multiscale numerical model of the Storegga slide-generated tsunami where spatial resolution varies from 500 m to 50 km across the entire Norwegian-Greenland sea domain to optimally resolve the slide region, important coastlines and bathymetric changes. We compare results from our multiscale model to previous results using constant-resolution models and show that accounting for changes in bathymetry since 8.15 ka, neglected in previous numerical studies of the Storegga slide-tsunami, improves the agreement between the model and inferred run-up heights in specific locations, especially in the Shetlands, where maximum run-up height increased from 8 m (modern bathymetry) to 13 m (palaeobathymetry). By tracking the Storegga tsunami as far south as the southern North sea, we also found that wave heights were high enough to inundate Doggerland, an island in the southern North Sea prior to sea level rise over the last 8 ka. 相似文献
11.
12.
This paper provides an overview of a new large scale laboratory data set on the kinematics of breaking tsunami wavefronts. The aim of the experiments was to provide an open access data set for model testing, calibration and verification, with particular emphasis on fluid kinematics in the wave breaking and run-up (swash) zones. The experiments were performed over a composite slope in the tsunami wave basin at the O. H. Hinsdale Wave Research Laboratory at Oregon State University. Data for ten different wave conditions were collected, including non-breaking and breaking waves, and both shore breaks and fully developed long bores.Surface elevation and fluid kinematics were measured with a closely spaced array of surface piercing wave gauges, non-contact ultrasonic wave gauges and four 3-D side-looking Acoustic Doppler Velocimeters. The array was traversed from the nearshore (depth = 0.2 m) to the middle and upper run-up zone, providing kinematic data at 30 cross-shore locations. Video was also recorded from 4 cameras covering the propagation, breaking and run-up zones. Surface elevation, flow velocities and the wave maker displacement were also recorded to provide offshore boundary conditions.The experiments include conditions with wave heights up to 0.55 m, notional wave periods up to 20 s and run-up lengths of up to 15.2 m on a 1/30 slope. In terms of the slope in the shoaling and breaker zones, the data correspond to Iribarren numbers in the range of 0.26–5.6. Raw, calibrated and processed data are stored with open access within the OSU Tsunami Wave Basin Experiment Notebook, which provides full access to all the wave maker control signals, data, instrument coordinates, and processing and plotting software. This paper serves as an introduction to the data set, demonstrates data quality and provides an initial analysis of some key parameters that govern the impact of tsunami events, including run-up versus offshore wave conditions and nearshore bore height, the maximum inundation depths at the original shoreline position, and the time to maximum inundation depth and flow reversal. Examples of temporal and convective accelerations and turbulent flow components are also presented to illustrate further details of the kinematics. 相似文献
13.
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
14.
Dune erosion is shown to occur at the embayment of beach mega-cusps O(200 m alongshore) that are associated with rip currents. The beach is the narrowest at the embayment of the mega-cusps allowing the swash of large storm waves coincident with high tides to reach the toe of the dune, to undercut the dune and to cause dune erosion. Field measurements of dune, beach, and rip current morphology are acquired along an 18 km shoreline in southern Monterey Bay, California. This section of the bay consists of a sandy shoreline backed by extensive dunes, rising to heights exceeding 40 m. There is a large increase in wave height going from small wave heights in the shadow of a headland, to the center of the bay where convergence of waves owing to refraction over the Monterey Bay submarine canyon results in larger wave heights. The large alongshore gradient in wave height results in a concomitant alongshore gradient in morphodynamic scale. The strongly refracted waves and narrow bay aperture result in near normal wave incidence, resulting in well-developed, persistent rip currents along the entire shoreline.
The alongshore variations of the cuspate shoreline are found significantly correlated with the alongshore variations in rip spacing at 95% confidence. The alongshore variations of the volume of dune erosion are found significantly correlated with alongshore variations of the cuspate shoreline at 95% confidence. Therefore, it is concluded the mega-cusps are associated with rip currents and that the location of dune erosion is associated with the embayment of the mega-cusp. 相似文献
15.
Lou Jing P.V. Ridd C.L. Mayocchi M.L. Heron 《Estuarine, Coastal and Shelf Science》1996,42(6):787-802
Waves propagating from deep water into shallow coastal areas produce oscillatory currents near the sea bottom. The magnitude of these currents depend upon the period and amplitude of the incoming waves, and the dissipation mechanism such as wave breaking and bottom friction. Field experiments in a gently shoaling bay, i.e. Cleveland Bay, Northern Australia, showed that there is a broad band of water at around 6 m depth, where the benthic surge velocities are maximum. Both further inshore and offshore, the bottom velocities were less than at 6 m depth, contrary to the normal expectation that the velocities should increase as the water becomes shallower. A new and computationally efficient wave model was developed and was able to reproduce experimental results for waves above 50 cm wave height, but not for small waves (wave height about 30 cm). One implication of this higher band of benthic surge velocities may be to produce high water turbidities in this region. Turbidity data from Cleveland Bay is consistent with this hypothesis. 相似文献
16.
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
17.
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
18.
I. I. Didenkulova A. A. Kurkin E. N. Pelinovsky 《Izvestiya Atmospheric and Oceanic Physics》2007,43(3):384-390
The problem of sea-wave run-up on a beach is discussed within the framework of exact solutions of a nonlinear theory of shallow water. Previously, the run-up of solitary waves with different forms (Gaussian and Lorentzian pulses, a soliton, special-form pulses) has already been considered in the literature within the framework of the same theory. Depending on the form of the incident wave, different formulas were obtained for the height of wave run-up on a beach. A new point of this study is the proof of the universality of the formula for the maximum height of run-up of a solitary wave on a beach for the corresponding physical choice of the determining parameters of the incident wave, so that the effect of difference in form is eliminated. As a result, an analytical formula suitable for applications, in particular, in problems related to tsunamis, has been proposed for the height of run-up of a solitary wave on a beach. 相似文献
19.
This paper presents the results of a parametric study of irregular wave run-up over fringing reefs using the shock-capturing Boussinesq wave model Funwave-TVD to better understand the role of fringing reefs in the mitigation of wave-driven flooding. Laboratory experiments were newly performed with a typical fringing reef profile and typical hydrodynamic conditions to validate the model. Experimental data shows irregular wave run-ups are dominated by the low-frequency motions and confirms the run-up resonant phenomenon over the back-reef slope, which has been revealed in previous numerical studies. It is demonstrated that irregular wave evolution and run-up over fringing reefs are reasonably reproduced by the present model with a proper grid size. However, the infragravity run-up height and highest 2% run-up height over the back-reef slope are under-predicted due to the underestimation of the infragravity wave height over the reef flat. The validated model was then utilized to model irregular wave transformations and run-ups under different conditions. Through a series of numerical experiments, the effects of key hydrodynamic and reef geometry parameters, including the reef flat width, water depth over the reef flat, fore-reef slope angle and back-reef slope angle, on the irregular wave run-up were investigated. Variations of spectral components of irregular wave run-ups were examined to better understand the physical process underlying the effect of each parameter. 相似文献
20.
The benthic fauna was studied in the Blagopoluchiya Bay (Kara Sea, Novaya Zemlya Archipelago) during an expedition of the R/V Professor Shtokman in autumn 2013. The inner basin of the bay, with depths of around 150 m, is separated from the outer slope of Novaya Zemlya by a shoal 30 m in depth. Six macrobenthic communities were described at nine stations (25 bottom grab samples) taken along a transect from the inner part of the bay to the outer part of the slope. The depths, position on the transect axis and sediment types were the major factors influencing the distribution of the communities. The benthic abundance and biomass in the inner and outer parts of the bay did not differ significantly. The diversity of macrobenthic organisms (α-diversity as the number of species in the sample and β-diversity as the rate of increase in species number in the area) was lower in the inner part of the bay. The intertidal zone (littoral) has been described. The littoral fauna was very poor; it comprised only the amphipods Gammarus setosus inhabiting the near-surface area. 相似文献