Wave Run-up Height Research Articles

Numerical modelling of wave run-up heights and loads on heaving buoy wave energy converter under the influence of regular waves

The effect of non-linear phenomenon such as wave run-up and wave impact on the heaving buoy wave energy converter may lead to its efficiency decrease and overtopping. In this study, a hydrodynamic simulation of wave run-up heights and maximum wave loads on a cylindrical heaving buoy is constructed and preliminarily analysed using the Reynolds-averaged Navier–Stokes equations. The numerical results show that kinetic energy is mainly concentrated in the wave-ward and leeward sides of the buoy. Further, the maximum pressure at the bottom of the buoy occurs on the leeward side when the wave hits the buoy, increasing by 47% over the initial pressure and 32% over the maximum pressure at the centre of the buoy. For a heaving buoy with the power take-off mechanism (PTO), the damping coefficient is the main parameter that affects the wave run-up and wave loads. By contrast, for a heaving buoy without PTO, the wave height and the radius of the buoy are the main parameter. The accuracy of the numerical results is verified through model tests of the motion response of the buoy and the wave surface characteristics around it. The computational method can guide future buoy designs in terms of safety and reliability.

Performance of submerged semi-circular breakwater under solitary wave in consideration of porous media

Submerged breakwater as the main structure of coastal engineering to protect coast is widely laid on the seabed because of its significant wave-dissipation performance. To reveal the interaction mechanism between waves and submerged breakwater, the hydrodynamic characteristics of a wave passing over different solid breakwaters were numerically and experimentally studied. Compared with the previous research, considering breakwater made up of porous media and the effects of extreme waves generated by hurricanes or tsunamis, this paper systematically investigates the effects of the semi-circular porous medium breakwater on the breaking solitary wave run-up based on a numerical model with the immersed boundary (IB) method. The computational capability of this model is verified firstly. Then, depending on the model, a series of cases are carried out to research the effects of different breakwaters on the run-up of solitary waves. The results show that the influence of porous breakwater on wave propagation is more significant than that of the solid breakwater. With the increase of the gravel particle median diameter, the maximum run-up height and the horizontal hydrodynamic force on the breakwater decrease, while the vertical hydrodynamic force on the breakwater increases. Increasing the size of the breakwater is beneficial to reducing the wave run-up height and the forces on the sloping beach. Compared with the single breakwater, the impact of the tandem breakwater on the wave propagation is more significant.

Tsunami Squares modeling of the 2007 Dayantang landslide generated waves considering the effects in slide/water interactions

Landslide tsunami in reservoirs can inflict serious consequences and they have aroused social concern worldwide. Herein, we introduce a historical reservoir tsunami that occurred on June 2007 in Shuibuya Reservoir, China. After a progressive failure over 20 days, the Dayantang slope with a volume of 3 million cubic meters slid into the Shuibuya Reservoir and spawned a giant tsunami that ran up ~50 m on the opposite shoreline and caused disastrous consequences. To model the 2007 tsunami, we apply a meshless numerical approach called ‘Tsunami Squares’ (TS) that takes into account the landslide/water interactions. TS simulates both the landslide and its generated tsunami and introduces ‘Push Ahead’ (PA) and ‘Drag Along’ (DA) accelerations to mimic the physical mechanics in the process. The accuracy and efficiency of TS method are verified by a well-designed landslide tsunami experiment that compares the observed wave dynamics with the ones simulated by TS and achieves an excellent match between the two. Landslide simulations indicate a maximum impact velocity of ~20 m/s and that the computed post-slide mass stopped on the near river bed with a shape coinciding with the field observations. Wave simulations present a large region of wave impacts and a maximum wave runup height of 52.9 m at the opposite bank facing the landslide scarp that is comparable to the observation (~50 m). Sensitivity analysis that compares the simulations with, and without, PA and DA accelerations is carried out both for the experimental wave and the 2007 one. This comparison indicates that TS simulations that do not include PA and DA can seriously underestimate landslide tsunami size. • Investigation of the geometric and geological conditions of the 2007 landslide tsunami • Update of the TS method by introducing PA and DA accelerations in landslide/water interactions • TS Model validation by a lab-scale wave experiment and application to the data-rich 2007 event • Sensitivity analysis of PA and DA accelerations that affects the landslide tsunami generation

Field measurements of very oblique wave run-up and overtopping with laser scanners

This paper presents the first field measurements with an innovative laser scanner system, during an actual severe winter storm with very oblique wave attack. The goal of this paper is to validate this innovative system for measuring wave run-up and wave overtopping parameters during storms with very oblique wave attack. The paper describes the analysis of the run-up and overtopping data obtained during storm Ciara (10 - 12 February 2020) and validates the results with data from overtopping tanks and video recordings. Storm Ciara was a highly unique and complex storm, with offshore-directed wind and alongshore-directed waves at the dike. This posed large challenges for measuring the front velocities. The wave run-up heights and the overtopping discharges could be measured accurately with the laser scanners. Reasonable results were achieved for the run-up depths. This has led to several new insights into the probability distribution of oblique wave run-up and the run-up depths of up-rushing oblique waves. Larger deviations were found for the 2D front velocities and wave angle of incidence, which could not be determined as well for storm Ciara. This arose from the highly complex conditions during Ciara with very oblique wave attack. The mobile system is now ready to be used at several different locations in the measurement campaign in this area over the coming years.

Assessment of natural coastal hazards at Alexandria/Nile Delta interface, Egypt

Recent in situ fine-grid waterfront survey integrated with inland elevation, nearshore depth soundings and wave data are incorporated into procedures for determining natural hazards, which are prevailing or expected at Alexandria/Nile delta interface on the Mediterranean Sea of Egypt. The hazards being assessed include wave runup height, inundation distance, rates of sea-level rise and shoreline change rate. The lateral variation of the hazard values along ~133.8 km which is the total length of the study coast helps with identifying six low-lying vulnerable spots with different potential hazards. Three vulnerable spots [2.3–2.5 m above mean sea level (msl)] are identified at Alexandria, specifically at the Eastern Harbor, Lauran and Mandara-Montaza beaches. In addition, three other low-lying spot areas are distinguished at Idku resort beach (1.0–1.5 m above msl) and on both sides of the western and eastern flanks of the Rosetta Nile promontory (1.0–1.2 m above msl). Detailed analysis of spatial and cross-shore transects generated from near shore/land elevation map marks contrasting elevations that vary from low-lying (− 3 m below msl) to high elevated carbonate ridges parallel to the shore (∼20 m above msl). The high-elevated coastal ridges underlying Alexandria’s seafront—maximum elevation of 12 m above msl—in addition to other protection elements are acting together as a natural quasi-barrier to mitigate sea flooding that may in turn affect the historical low-lying depressions located east and southeast of the city.

Wave Run-Up on Mortar-Grouted Riprap Revetments

The wave run-up height is a crucial design parameter that determines the crest height of a sea dike and is used for estimating the number of overtopping waves. Therefore, a reduction of the wave run-up height is generally aspired in the design of dikes, which can be achieved by mortar-grouted riprap revetments (MGRR). Although MGRRs are widely utilized revetments along the German North Sea coast, no investigations into the wave run-up height on this revetment type are available to date. Full-scale hydraulic model tests were hence conducted to investigate wave run-up heights on partially grouted and fully grouted MGRRs. The wave run-up was determined using 2D-LIDAR measurements, which were validated by video data. Partially grouted MGRRs, due to their roughness, porosity, and permeability, reduce wave run-up heights from 21% to 28%, and fully grouted MGRRs due to their roughness reduce wave run-up heights from 12% to 14% compared to smooth impermeable revetments. Influence factors have been determined for four widely used revetment configurations, which can now be used for design purposes. A comparison and subsequent discussion about the representation of the physics of wave run-up by different parameters is carried out with the results presented.

Characteristic of Wave Run-up on Schematic Precast System (SPS) Revetment

Revetment Sistem Panel Serbaguna (SPS) or Schematic System Precast (SPS) Revetment is latest innovation of SPS technology. It has been applied for various area of civil engineering such as bridge, dams and irrigation channel. For this upgrading, SPS has been tested in Hydraulic Laboratory of Experimental Station for Coastal Engineering Ministry of Public Works and Housing as revetment. SPS is tested with 14 scenarios of various wave steepness and water depth to determine the wave run-up characteristic. All hydraulic performance of SPS for each scenario is recorded with video camera. Using image processing technique, we calculate the wave run-up height for each scenario. From all scenarios, the wave run-up only happen in scenarios with water depth of 0.65 m while the rest only experience wave overtopping. Comparing to the classical Iribarren Number graph, relative wave run-up height on SPS revetment is higher than other type of revetment such as Riprap Arhens, Riprap Gunbak, Batu Pecah, Qudripod, Dolos and Tetrapod but below Sisi Miring. For Sisi Miring Revetment, the maximum relative wave run-up height (Ru/Hm0) is 2.5 for Iribarren Number (Ir) = 2.5 as for SPS revetment, it is approximately 2.4 for Ir = 11.

Operational monitoring and forecasting of wave run-up on seawalls

In this work, a wave run-up monitoring system and a model for forecasting the wave run-up height on a seawall were developed. Electrical conductivity sensors were installed on the seaward slopes of seawalls to measure the wave run-up heights. The general packet radio service protocol was used to transmit the measured data in real time to the desired remote location. The Princeton Ocean Model and WAVEWATCH III were used to predict the water levels and ocean waves, respectively, by using the available wind fields. The empirical formulas recommended in the Coastal Engineering Manual (2011) and EurOtop (2018) were adopted to estimate the run-up height. The wave run-up heights were forecasted 72 h in advance and were renewed at 6-h intervals as new wind fields became available. The developed monitoring system and forecasting model were combined for operational monitoring and forecasting of wave run-up on seawalls. The wave run-up monitoring system was set up at three seawalls along the southwestern coast of Taiwan from 2013 to 2016. Consistency between the forecasted and measured wave run-up heights during typhoon periods demonstrated the feasibility of using the proposed method for monitoring and forecasting wave run-up heights. Furthermore, the multi-model ensemble approach was adopted to improve the unsatisfactory run-up forecasting performance during typhoon periods, and the forecasted run-up heights were eventually presented as a band with upper and lower limits as opposed to single values. The forecast results can be used to provide advance warning of possible wave overtopping and associated coastal flooding during typhoon periods.

Extreme Inundation Statistics on a Composite Beach

The runup of initial Gaussian narrow-banded and wide-banded wave fields and its statistical characteristics are investigated using direct numerical simulations, based on the nonlinear shallow water equations. The bathymetry consists of the section of a constant depth, which is matched with the beach of constant slope. To address different levels of nonlinearity, time series with five different significant wave heights are considered. The selected wave parameters allow for also seeing the effects of wave breaking on wave statistics. The total physical time of each simulated time-series is 1000 h (~360,000 wave periods). The statistics of calculated wave runup heights are discussed with respect to the wave nonlinearity, wave breaking and the bandwidth of the incoming wave field. The conditional Weibull distribution is suggested as a model for the description of extreme runup heights and the assessment of extreme inundations.

Tsunamiopasnost' Krymskogo poberezh'ya Chernogo morya i Kerchenskogo proliva pri katastroficheskih tsunamigennyh zemletryaseniyah, blizkih po lokalizatsii k istoricheskomu YAltinskomu zemletryaseniyu 12 sentyabrya 1927 goda

Purpose. The main purpose of the work is to assess a possible tsunami hazard for the region of location of the Crimean Bridge constructed across the Kerch Strait, since up to present, numerical simulations of the tsunamigenic earthquakes in the Black Sea have never taken the Kerch Strait region (except for the water area at the strait entrance) into consideration as a possible object for a tsunami hazard. Methods and Results. To assess a tsunami hazard for the Kerch Strait and, particularly, for the region of location of the constructed Crimean Bridge, the present paper considers the historical catastrophic tsunamigenic earthquake in the southeastern part of the Crimea Peninsula on September 12, 1927 as well as possible strong earthquakes, the source locations and magnitudes of which can be close to those of the above-mentioned one. The available data on localization and intensity of the earthquake on September 12, 1927 allowed to model the source of such an earthquake. Besides, within the framework of the nonlinear shallow water equations, simulated were the tsunami generation and the tsunami waves’ propagation from the single- and two-block seismic sources in the Black Sea along the Crimea Peninsula, at the Kerch Strait entrance and in its water area. The seismic sources of close localization were similarly simulated for two possible tsunamigenic earthquakes in the southeastern part of the Crimea Peninsula. Conclusions. For all the considered scenarios, generation and propagation of the tsunami waves over the water area regions under study were numerically simulated, the histograms of distribution of the wave run-up maximum heights along the Crimea Peninsula and the Kerch Strait coasts were constructed. It is shown that for all the scenarios, in the region of the Crimean Bridge western pillars the tsunami wave heights do not exceed 0.3–0.5 m, whereas in the region of its eastern pillars, possible wave heights are within the range 0.6–1.95 m. The results represented in the paper are compared with the available data on the wave heights in a number of settlements of the Crimea Peninsula coast and at the Kerch Strait entrance, obtained by the other authors.

Numerical Study of the Impact of Climate Change on Irregular Wave Run-up Over Reef-Fringed Coasts

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 back-reef 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.

Effect of wave steepness to relative wave run-up on OWEC breakwater

OWEC (Overtopping Wave Energy Converter) breakwater is a coastal structure model concept. The concept is to integrate the breakwater and the overtopping wave energy converter. This coastal protection model concept is equipped with a reservoir at the top of the structure to collect water that overflows from the top of the structure (overtopping). Many factors influence the amount of wave overtopping discharge; one of them is the run-up height. The height of wave run-up that occurs is influenced by many factors, one of which is the steepness of the incoming wave. The effect of the wave steepness to the relative wave run-up on OWEC breakwater is investigated experimentally. The study is carried out in wave flume with regular waves. The OWEC breakwater model is simulated with slope variations and freeboard variations. The results of the study show that small wave steepness value produces a large relative wave run-up value and vice versa. For a review of the structure slope, the results showed that the largest relative run-up value was obtained in the largest slope of the variation of the slope studied, namely 1: 2, at all different freeboard heights.

Indication of Holocene sea-level stability in the southern Laptev Sea recorded by beach ridges in north-east Siberia, Russia

The rapid warming of the Arctic may affect the stability of coastal geomorphological systems. Prograded sequences of wave-built deposits, so-called beach-ridge systems, preserve a proxy record of the long-term variability in the drivers of coastal evolution. Information on relative sea level (RSL), climate forcing and sediment supply can be reconstructed from these archives. Buor Khaya Bay is one of the few places along the Siberian Arctic coast where wide beach-ridge systems exist. A previously undescribed field site was surveyed in order to obtain information on the geomorphological processes along the modern shoreline under the current environmental conditions, and the characteristics of the Holocene beach-ridge deposits (e.g., elevation, sediment and age). Our data show that the system formed under storm wave/surge conditions. The beach ridges prograded ca. 1100 m between 6200 and 2600 cal yr BP, with only minor variations in surface elevation. This suggests a continuous and high sediment supply and similar storm wave run-up heights during that time. This relationship is interpreted as indicating RSL stability at a similar-to-present elevation during the period of beach-ridge formation. The hiatus in coastal progradation is concurrent with a deteriorating climate (cooling) in the Laptev Sea area and our data hence suggest increased rates of coastal change during periods of warmer climate conditions. Our study illustrates the potential of coastal sedimentary archives to provide a more complete view of the forcing, resilience and long-term evolution of unconsolidated Arctic coasts in a changing environment.

Numerical investigation of breaking solitary wave runup on permeable sloped beach using a nonhydrostatic model

The wave profile of solitary wave has been widely used as a tsunami paradigm for decades to capture the main features of actual tsunamis. Since most of the fatalities were attributed to overland flow of tsunamis, the runup and rundown processes of solitary waves have been extensively studied experimentally and numerically. Comparing to previous research, this paper systematically investigates the hydrodynamic characteristics of breaking solitary wave runup on a permeable sloped beach using a nonhydrostatic model. Firstly, the computational capabilities of present numerical model in predicting solitary wave runup process and flow field in permeable media are well validated with experimental data. Then, a series of computational runs have been performed to study the breaking solitary wave on permeable sloped beach. Effects of three prominent factors on the maximum runup height of breaking solitary wave are considered in detail: the thickness (B), median diameter (d50), and porosity (n) of the permeable layers. The porosity of the beach has a substantial impact on the flow field for breaking waves running up a sloped beach. The maximum wave runup height can be substantially reduced if the permeability of the beach is considered. It is also found that the maximum wave runup height decreases with permeable layer thickness. However, the reduction rate gradually decreases. The influences of median diameter are very limited and can be ignored. In addition, based on our results, we also proposed a new empirical formula to calculate the maximum wave runup height of breaking solitary wave on permeable sloped beach. The findings of this paper are expected to be useful for developing an improved understanding on the runup processes of breaking solitary wave on sloped beach with some permeability.

Run-up of nonlinear monochromatic wave on a plane beach in presence of a tide

The nonlinear problem of long wave run-up on a plane beach in a presence of a tide is solved within the shallow water theory using the Carrier-Greenspan approach. The exact solution of the nonlinear problem for wave run-up height is found as a function of the incident wave amplitude. Influence of tide on characteristics of wave run-up on a beach is studied.

Characteristics of wave attenuation due to roughness of stepped obstacles

ABSTRACT In this study, we investigated the energy dissipation characteristics of stepped obstacles by using both the regular and irregular waves in a physical wave flume. The stepped obstacle used in this study is different from those of traditional stepped dikes with fixed horizontal and vertical stage surfaces; here, the angle of the stepped surface varies with the slope of the embankment surface, with various interaction angles between the incident waves and the rough stepped surfaces. The stepped embankments were composed of six types of stepped arrangements and were used to analyse the wave run-up heights and reflection coefficients; in addition, the variations in energy dissipation effects were also studied. The results identify two of the six roughness types that have better mitigation effects on the investigated the energy dissipation characteristics of stepped obstacles. The reflection coefficient is larger for a submerged dike with a rough surface than for one with a smooth surface.

Wave Run-up Modeling with Adaptive Mesh Refinement (AMR) Method in the Busan Marine City during Typhoon Chaba (1618)

Park, J.H.; Yuk, J.H.; Joo. W.K. and Lee. H.S., 2019. Wave run-up modeling with adaptive mesh refinement (AMR) method in the Busan Marine City during typhoon Chaba (1618). In: Lee, J.L.; Yoon, J.-S.; Cho, W.C.; Muin, M., and Lee, J. (eds.), The 3rd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 91, pp. 56-60. Coconut Creek (Florida), ISSN 0749-0208.The accuracy of numerical calculations is highly dependent on the grid spacing, and the smaller the grid spacing the better the accuracy. However, the portion requiring high accuracy often corresponds to only a part of the entire model domain. Setting a small grid interval for the entire model domain to study the calculation region is undesirable from the viewpoint of computation load and computation time. In this study, we illustrate the efficiency of the adaptive mesh refinement method for wave run-up modelling in terms of computational time and accuracy using numerical experiments. In this study, we conducted numerical experiments of wave run-up to verify the efficacy of the Adaptive Mesh Refinement (AMR) method in terms of accuracy and computation load for typhoon Chaba (1618). We determined that wave propagation modelling with storm surge height using the AMR method might be a good alternative to calculated wave run-up height. The difference between the observed and AMR model values for wave run-up height was calculated to be less than 1 m. Compared to the results of non-adaptive experiments with fixed spatial resolutions, those with the AMR method produced highly accurate results, while requiring only 75% of the computation time. The estimation of wave run-up height using AMR is expected to allow the accurate estimation of coastal inundation if more accurate topography and input conditions are given.

Numerical simulation of maximum wave loads and run-up heights on offshore wind turbine foundations influenced by the instability of bichromatic wave groups

In this paper, maximum wave loads and run-up heights around the columns of Offshore Wind Turbine (OWT) foundations for different types by adopting a normalized modulation parameter δˆ were preliminarily analyzed. In order to simulate the evolution of modulated wave groups, bichromatic waves were selected and validated by the experimental data of Tainan Hydraulics Laboratory. The accuracy of wave-structure interaction was also examined by comparing with the model tests of wave loads for the jacket support structure in the wave flume. The quasi-static force and the dynamic force would be separated by using the band-pass filter. In terms of the quasi-static force, it can be estimated by the monochromatic wave and be calibrated in the Morison's load formula. By means of the deconvolution method, the maximum force is well calculated for further obtaining the impact coefficient. The impact coefficients subject to δˆ for different OWT foundations were also summarized. Meanwhile, the normalized run-up heights around the columns of OWT foundations would be discussed qualitatively and quantitatively. Eventually, the impact coefficient and the normalized run-up height would be discussed according to the variation of the curling factor in different wave conditions.

Run-Up of a Nonlinear Monochromatic Wave on a Plane Beach in Presence of a Tide

The nonlinear problem of long wave run-up on a plane beach in a presence of a tide is solved within the shallow water theory using the Carrier-Greenspan approach. The exact solution of the nonlinear problem for wave run-up height is found as a function of the incident wave amplitude. Influence of tide on characteristics of wave run-up on a beach is studied.

The influence of climate change on tsunami-like solitary wave inundation over fringing reefs

ABSTRACTThe protective capability of fringing reefs against tsunami hazards has been reported in numerous post-disaster surveys. It is believed that global warming is changing the water level over the reef flat and reef surface roughness by sea-level rise and coral bleaching. For a better understanding of the influence of climate change on tsunami hazards over fringing reefs, this study utilized a shock-capturing Boussinesq wave model, FUNWAVE-TVD, to simulate the tsunami-like solitary wave propagation and run-up over fringing reefs. Calibrated and validated by the newly obtained experimental data, the present model with shock-capturing scheme, in which only the ratio of wave height to water depth is used to trigger wave breaking, shows reasonable prediction of solitary wave transformation and run-up height over sharply varying reef bathymetry. Numerical experiments were then carried out to investigate the effects of sea-level rise and degrading of the reef surface roughness on the solitary wave inundation distance and fluid force distribution in the inundation zone. Numerical results clearly demonstrate how tsunami hazards change within the inundation zone in response to higher water levels and lower reef roughness and suggest climate change, especially sea-level rise, will significantly increase tsunami hazards in the low-lying areas of the reef-lined coasts. Presented results are discussed for the effects of sea-level rise and coral bleaching on the solitary wave process and implications to further improve the resilience under the threat of climate change.