scholarly journals Numerical Investigations of Tsunami Run-Up and Flow Structure on Coastal Vegetated Beaches

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1776 ◽  
Author(s):  
Hongxing Zhang ◽  
Mingliang Zhang ◽  
Tianping Xu ◽  
Jun Tang
Keyword(s):  
Wave Propagation ◽  
Numerical Model ◽  
Peak Flow ◽  
Tsunami Wave ◽  
Coastal Vegetation ◽  
Coastal Forest ◽  
Governing Equations ◽  
Tsunami Waves ◽  
Run Up ◽  
Sloping Beach

Tsunami waves become hazardous when they reach the coast. In South and Southeast Asian countries, coastal forest is widely utilized as a natural approach to mitigate tsunami damage. In this study, a depth-integrated numerical model was established to simulate wave propagation in a coastal region with and without forest cover. This numerical model was based on a finite volume Roe-type scheme, and was developed to solve the governing equations with the option of treating either a wet or dry wave front boundary. The governing equations were modified by adding a drag force term caused by vegetation. First, the model was validated for the case of solitary wave (breaking and non-breaking) run-up and run-down on a sloping beach, and long periodic wave propagation was investigated on a partially vegetated beach. The simulated results agree well with the measured data. Further, tsunami wave propagation on an actual-scale slope covered by coastal forest Pandanus odoratissimus (P. odoratissimus) and Casuarina equisetifolia (C. equisetifolia) was simulated to elucidate the influence of vegetation on tsunami mitigation with a different forest open gap. The numerical results revealed that coastal vegetation on sloping beach has significant potential to mitigate the impacts from tsunami waves by acting as a buffer zone. Coastal vegetation with open gaps causes the peak flow velocity at the exit of the gap to increase, and reduces the peak flow velocity behind the forest. Compared to a forest with open gaps in a linear arrangement, specific arrangements of gaps in the forest can increase the energy attenuation from tsunami wave. The results also showed that different cost-effective natural strategies in varying forest parameters including vegetation collocations, densities, and growth stages had significant impacts in reducing the severity of tsunami damage.

scholarly journals Tsunami wave propagation by voronoi diagram

2018 ◽  
Vol 7 (3) ◽  
pp. 1233
Author(s):  
V Yuvaraj ◽  
S Rajasekaran ◽  
D Nagarajan
Keyword(s):  
Wave Propagation ◽  
Voronoi Diagram ◽  
Tsunami Wave ◽  
Fast Marching Method ◽  
Coastal Regions ◽  
Fast Marching ◽  
Tsunami Waves ◽  
The Finite Difference Method ◽  
Run Up ◽  
Marching Method

Cellular automata is the model applied in very complicated situations and complex problems. It involves the Introduction of voronoi diagram in tsunami wave propagation with the help of a fast-marching method to find the spread of the tsunami waves in the coastal regions. In this study we have modelled and predicted the tsunami wave propagation using the finite difference method. This analytical method gives the horizontal and vertical layers of the wave run up and enables the calculation of reaching time.  

scholarly journals Estimates of Amplitude Characteristics of Tsunami Wave Run-Up in Various Areas of the Black Sea Coast

2021 ◽  
Author(s):  
A. Yu. Belokon ◽  
Keyword(s):  
Wave Propagation ◽  
Sea Level ◽  
Black Sea ◽  
Tsunami Wave ◽  
Computational Modelling ◽  
Wave Model ◽  
The Black Sea ◽  
Tsunami Propagation ◽  
Tsunami Waves ◽  
Run Up

This paper is devoted to computational modelling of tsunami wave propagation and runup to the shore for some points on the Russian, Turkish, Bulgarian and Ukrainian coasts of the Black Sea. The nonlinear long wave model was used to solve the problem of wave propagation from hydrodynamic tsunami sources, which can constitute the greatest potential danger for the studied coast areas. The hydrodynamic sources were set in the form of an elliptical elevation, the parameters of which were chosen according to the sea level response to an underwater earthquake of magnitude 7. All the sources were located in seismically active areas, where tsunamigenic earthquakes had already occurred, along the 1500 m isobath. Near each of the studied points in the area above 300 m depths, we calculated marigrams, i.e. time-series of sea level fluctuations caused by the passage of waves. Then, a one-dimensional problem of tsunami propagation and run-up on the coast was solved for each of the points under study, where the obtained marigrams were used as boundary conditions. Peculiarities of tsunami wave propagation have been shown depending on the bottom and land relief in the studied areas of the Black Sea. Estimates have been obtained of the sea level maximum rise and fall during surge and subsequent coastal drainage for the characteristic scales of relief irregularity at different points. For possible tsunamigenic earthquakes, the largest splashes may occur in the region of Yalta (2.15 m), Cide (1.9 m), Sevastopol (1.4 m), and Anapa (1.4 m). Tsunami propagation in the Feodosiya and Varna coastal areas is qualitatively similar, with maximum wave heights of 0.64 m and 0.46 m, respectively. The coastlines of Evpatoriya (0.33 m) and Odessa (0.26 m) are least affected by tsunami waves due to the extended shelf.

scholarly journals Physical and Numerical Modelling of Tsunami Run-up on Seawall at Sloping Beach

2019 ◽  
Vol 5 (2) ◽  
pp. 139
Author(s):  
Ma'ruf Hadi Sutanto
Keyword(s):  
Numerical Model ◽  
Water Depth ◽  
Tsunami Wave ◽  
Peak Height ◽  
Initial Water ◽  
Tsunami Mitigation ◽  
Run Up ◽  
Tsunami Run Up ◽  
Sloping Beach ◽  
Reduction Percentage

Tsunami run-up on land has a large destructive power. Further studies are deemed necessary to understand the process and characteristics of tsunami run-up in coastal areas. Seawall structures can reduce the run-up of a tsunami depending on the height of the seawall crest. Physical modeling shows that seawall may significantly reduce run-up (𝑅) and inundation (𝑋𝑖). The highest reduction up to 55% where the seawall peak height is 7 cm and the water depth is 15 cm. With the same scenario in numerical modeling, the percentage reduction is 67.53%. The highest inundation (Xi) in the scenario without seawall structure is 6.081 m when the initial water depth (d0) equals to 30 cm. The result of the numerical model for the same scenario is 6.970 m. Seawall as tsunami mitigation structure is only effective when the tsunami wave is relatively low compared to the seawall height (H/ sw). Reduction percentage > 25%, with conditions that H/ sw is < 0.856 (physical model) and < 0.802 (numerical model).

Two-Layer Non-Hydrostatic Scheme for Simulations of Wave Runup

2019 ◽  
Vol 13 (05n06) ◽  
pp. 1941004 ◽  
Author(s):  
M. A. Ginting ◽  
S. R. Pudjaprasetya ◽  
D. Adytia
Keyword(s):  
Wave Propagation ◽  
Solitary Wave ◽  
Water Waves ◽  
Tsunami Wave ◽  
Harmonic Wave ◽  
Laboratory Data ◽  
Analytical Formula ◽  
Wave Simulation ◽  
Run Up ◽  
Sloping Beach

There are indisputable research supporting scientific argument that propagation of (tsunami) wave from intermediate depth towards shallower coastal area needs dispersive wave model. For tsunami wave simulation, efficiency of the numerical scheme is an important issue. In this paper, the two-layer non-hydrostatic model as developed previously in Pudjaprasetya et al. [2017] “A non-hydrostatic two-layer staggered scheme for transient waves due to anti-symmetric seabed thrust,” J. Earthquake Tsunami  11, 1–17, to study tsunami generation and propagation, is adopted. Restricting to 1+1 dimension, here, we focus on the performance of the scheme in simulating wave propagation in coastal areas, in particular predicting the run-up height. First, we conducted a simulation of harmonic wave over a sloping beach to conform the analytical shoreline motion by Carrier and Greenspan [1958] “Water waves of finite amplitude on a sloping beach,” J. Fluid Mech.  4, 97–109. The ability of the scheme in accommodating dispersion and non-linearity were shown via simulation of a solitary wave that propagates over a flat bottom. This solitary wave simulation provides an evaluation of the convergence aspect of the model. Further, several benchmark tests were conducted; a solitary wave over a sloping beach to mimic the experimental data by Synolakis [1986] “The run-up of solitary waves,” J. Fluid Mech.  185, 523–545, as well as solitary wave over a composite beach. Good agreement with laboratory data was obtained in terms of wave signal, whereas for relatively low amplitude, the solitary run-up height conforms the analytical formula. Moreover, the scheme is tested for simulating the Beji–Battjes experiment Beji, S. and Battjes, J. A. [1993] “Experimental investigation of wave propagation over a bar,” Coast. Eng.  19, 151–162. As well as wave focusing experiment by Kurnia et al. [2015] “Simulations for design and reconstruction of breaking waves in a wavetank,” Proc. ASME 2015 34th Int. Conf. Ocean, Offshore and Arctic Engineering, Newfoundland, Canada, 31 May–5 June 2015, pp. 2–7.

scholarly journals Multi-method observation and analysis of an impulse wave and tsunami caused by glacier calving

2015 ◽  
Vol 9 (6) ◽  
pp. 6471-6493 ◽  
Author(s):  
M. P. Lüthi ◽  
A. Vieli
Keyword(s):  
Tsunami Wave ◽  
Tide Gauge ◽  
Impulse Wave ◽  
West Greenland ◽  
Tsunami Waves ◽  
The Future ◽  
History Of ◽  
Impulse Waves ◽  
Run Up

Abstract. Glacier calving can cause violent impulse waves which, upon landfall, can lead to destructive tsunami-like waves. Here we present data acquired during a calving event from Eqip Sermia, an ocean-terminating glacier in West Greenland. During an exceptionally well documented event, the collapse of 9 × 105 m3 ice from a 200 m high ice cliff caused an impulse wave of 50 m height, traveling at a speed of 25–30 m s-1. This wave was filmed from a tour boat in 800 m distance from the calving face, and simultaneously measured with a terrestrial radar interferometer and a tide gauge. Tsunami wave run-up height on the steep opposite shore in 4 km distance was 10–15 m, destroying infrastructure and eroding old vegetation. These observations indicate that such high tsunami waves are a recent phenomenon in the history of this glacier. Analysis of the data shows that only moderately bigger tsunami waves are to be expected in the future, even under rather extreme scenarios.

scholarly journals Tsunami Intrusion and River Ice Movement

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1290 ◽  
Author(s):  
Jiajia Pan ◽  
Hung Tao Shen
Keyword(s):  
Wave Propagation ◽  
Tsunami Wave ◽  
Water Pressure ◽  
Time Integration ◽  
Boussinesq Equations ◽  
Wave Model ◽  
Hybrid Technique ◽  
Ice Dynamics ◽  
Tsunami Waves ◽  
Surface Ice

A two-dimensional wave model coupled with ice dynamics is developed to evaluate ice effects on shallow water wave propagation on a beach and in a channel. The nonlinear Boussinesq equations with ice effects are derived and solved by the hybrid technique of the Godunov-type finite volume method and finite difference method with the third-order Runge–Kutta method for time integration. The shock capturing method enables the model to simulate complex flows over irregular topography. The model is capable of simulating wave propagations accurately, including non-hydrostatic water pressure and wave dispersions. The ice dynamic module utilizes a Lagrangian discrete parcel method, based on smoothed particle hydrodynamics. The Boussinesq wave model is validated with an analytical solution of water surface oscillation in a parabolic container, an analytical solitary wave propagation in a flat channel, and experimental data on tsunami wave propagations. The validated model is then applied to investigate the interaction between ice and tsunami wave propagation, in terms of ice attenuation on tsunami wave propagations over a beach, ice deposition on the beach driven by the tsunami wave, and ice jam formation and release in a coastal channel with the intrusion of the tsunami wave. The simulated results demonstrated the interactions between tsunami waves and surface ice, including the maximum run up, ice movement along the beach, and ice jamming in a channel.

scholarly journals Study on Analytical Modelling of Tsunami Wave Propagation

2020 ◽  
Author(s):  
Yasmin Regina M ◽  
Syed Mohamed E
Keyword(s):  
Wave Propagation ◽  
Arrival Time ◽  
Tsunami Wave ◽  
Wave Train ◽  
Deep Ocean ◽  
Vital Role ◽  
The People ◽  
Run Up ◽  
Short Time ◽  
Tsunami Amplitude

Modelling of tsunami wave propagation plays a vital role in forecasting of disastrous tsunami. The earlier identification and prediction of tsunami provides more time for taking preventive measures and evacuation. On December 26, 2004, massive destruction of lives and properties due to tsunami increases the needs to develop a fast and accurate modelling of tsunami wave propagation. The modelling of waves provide the amplitude of tsunami, speed, arrival time and power of the wall of water and also run up distance and height. It also used to predict vulnerable buildings to tsunami. In this paper describes the modelling of tsunami wave propagation from generation to run-up. Numerical and analytical methods used for modelling and simulation. Tsunami is serious of wave (wave train) which has a long wavelength >500 km and celerity of wave more than 800 km/hr in deep ocean and in shallow coast, their wavelength and celerity diminishes but the amplitude of wave increases above 30m. The scope of this study is to determine the areas which are going to hit by tsunami, amplitude of wave and their arrival time for early forecasting and alert the people within a short time after an earthquake happened.

scholarly journals Staggered Conservative Scheme for 2-Dimensional Shallow Water Flows

Fluids ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 149
Author(s):  
Novry Erwina ◽  
Didit Adytia ◽  
Sri Redjeki Pudjaprasetya ◽  
Toni Nuryaman
Keyword(s):  
Wave Propagation ◽  
Numerical Model ◽  
Solitary Wave ◽  
Shallow Water ◽  
Threshold Value ◽  
Staggered Grid ◽  
Conservative Scheme ◽  
Shallow Water Flows ◽  
Run Up ◽  
N Wave

Simulating discontinuous phenomena such as shock waves and wave breaking during wave propagation and run-up has been a challenging task for wave modeller. This requires a robust, accurate, and efficient numerical implementation. In this paper, we propose a two-dimensional numerical model for simulating wave propagation and run-up in shallow areas. We implemented numerically the 2-dimensional Shallow Water Equations (SWE) on a staggered grid by applying the momentum conserving approximation in the advection terms. The numerical model is named MCS-2d. For simulations of wet–dry phenomena and wave run-up, a method called thin layer is used, which is essentially a calculation of the momentum deactivated in dry areas, i.e., locations where the water thickness is less than the specified threshold value. Efficiency and robustness of the scheme are demonstrated by simulations of various benchmark shallow flow tests, including those with complex bathymetry and wave run-up. The accuracy of the scheme in the calculation of the moving shoreline was validated using the analytical solutions of Thacker 1981, N-wave by Carrier et al., 2003, and solitary wave in a sloping bay by Zelt 1986. Laboratory benchmarking was performed by simulation of a solitary wave run-up on a conical island, as well as a simulation of the Monai Valley case. Here, the embedded-influxing method is used to generate an appropriate wave influx for these simulations. Simulation results were compared favorably to the analytical and experimental data. Good agreement was reached with regard to wave signals and the calculation of moving shoreline. These observations suggest that the MCS method is appropriate for simulations of varying shallow water flow.

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