scholarly journals NUMERICAL AND EXPERIMENTAL STUDY ON TSUNAMI RUN-UP AND INUNDATION INFLUENCED BY MACRO ROUGHNESS ELEMENTS

2011 ◽  
Vol 1 (32) ◽  
pp. 13 ◽  
Author(s):  
Nils Goseberg ◽  
Torsten Schlurmann

This research study considers long wave run-up experimentally and numerically. At first, an alternative methodology in long wave physical modeling is presented by means of a set of pipe pumps forcing the inflow of a controlled volume of water into a wave channel mimicking a tsunami-like wave shape that is consistently contained by a proportional plus integral plus derivative controller (PID) controller. Arbitrary wave lengths are persistently generated by means of the proposed methodology. First results are compared to tsunami data stemming from conventional experimental configurations with solitary waves as well as with recent numerical modeling results. Comparisons are thoroughly discussed and – in a second step – numerical simulations are accomplished taking the interaction of long wave run-up and macro-roughness elements into account. Four different experimental configurations of macro-roughness elements are carried out while spacing between elements and numbers of obstacle rows are alternated. A fundamental correlation analysis reveals that a correlation of the number of macro-roughness rows, effective area of flow cross section and a grouping factor of different element configurations exists in principle.

2012 ◽  
Vol 1 (33) ◽  
pp. 18 ◽  
Author(s):  
Nils Goseberg ◽  
Torsten Schlurmann

This paper reports experimental results of long wave run-up climbing up a 1:40 sloping beach. The resulting maximum run-up is compared with analytical results and a good agreement is found for single sinusoidal waves with uniform wave period and varying amplitude. Subsequently, the interaction with macro-roughness elements on the beach is investigated for different long-shore obstruction ratios. The reduction in wave run-up is expressed by means of a nomogram relating the wave run-up without macro-roughness elements present to those cases where on-land flow is modified by macro-roughness. The presented results mainly focus on a non-staggered and non-rotated macro-roughness configuration. In addition to the run-up reduction, surface elevation profiles on the shore are presented, that address the shock wave generation when the wave tongue approaches the first row of macro-roughness elements.


1970 ◽  
Vol 41 (3) ◽  
pp. 655-672 ◽  
Author(s):  
Conrad C. Lautenbacher

The refractive influence on tsunami run-up of the offshore bottom topography of islands is analyzed. Shallow water theory is used to treat problems in which the geometry resembles that of individual Hawaiian islands and in which the incident wave is plane and monochromatic.Mathematically, the differential equation for long-wave propagation is converted into an integral equation to which numerical methods are applied. Results of practical importance include the run-up on island coastal areas. The results are used in conjunction with earlier one-dimensional analyses to estimate the total tsunami run-up.


2021 ◽  
Vol 13 (7) ◽  
pp. 1399
Author(s):  
Quang Nguyen Hao ◽  
Satoshi Takewaka

In this study, we analyze the influence of the Great East Japan Earthquake, which occurred on 11 March 2011, on the shoreline of the northern Ibaraki Coast. After the earthquake, the area experienced subsidence of approximately 0.4 m. Shoreline changes at eight sandy beaches along the coast are estimated using various satellite images, including the ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer), ALOS AVNIR-2 (Advanced Land Observing Satellite, Advanced Visible and Near-infrared Radiometer type 2), and Sentinel-2 (a multispectral sensor). Before the earthquake (for the period March 2001–January 2011), even though fluctuations in the shoreline position were observed, shorelines were quite stable, with the averaged change rates in the range of ±1.5 m/year. The shoreline suddenly retreated due to the earthquake by 20–40 m. Generally, the amount of retreat shows a strong correlation with the amount of land subsidence caused by the earthquake, and a moderate correlation with tsunami run-up height. The ground started to uplift gradually after the sudden subsidence, and shoreline positions advanced accordingly. The recovery speed of the beaches varied from +2.6 m/year to +6.6 m/year, depending on the beach conditions.


Author(s):  
Jun Tang ◽  
Yongming Shen

Coastal vegetation can not only provide shade to coastal structures but also reduce wave run-up. Study of long water wave climb on vegetation beach is fundamental to understanding that how wave run-up may be reduced by planted vegetation along coastline. The present study investigates wave period influence on long wave run-up on a partially-vegetated plane slope via numerical simulation. The numerical model is based on an implementation of Morison’s formulation for rigid structures induced inertia and drag stresses in the nonlinear shallow water equations. The numerical scheme is validated by comparison with experiment results. The model is then applied to investigate long wave with diverse periods propagating and run-up on a partially-vegetated 1:20 plane slope, and the sensitivity of run-up to wave period is investigated based on the numerical results.


1991 ◽  
Vol 229 (-1) ◽  
pp. 675 ◽  
Author(s):  
Philip L.-F. Liu ◽  
Costas E. Synolakis ◽  
Harry H. Yeh

Author(s):  
Juh-Whan Lee ◽  
Jennifer L. Irish ◽  
Robert Weiss

Since near-field-generated tsunamis can arrive within a few minutes to coastal communities and cause immense damage to life and property, tsunami forecasting systems should provide not only accurate but also rapid tsunami run-up estimates. For this reason, most of the tsunami forecasting systems rely on pre-computed databases, which can forecast tsunamis rapidly by selecting the most closely matched scenario from the databases. However, earthquakes not included in the database can occur, and the resulting error in the tsunami forecast may be large for these earthquakes. In this study, we present a new method that can forecast near-field tsunami run-up estimates for any combination of earthquake fault parameters on a real topography in near real-time, hereafter called the Tsunami Run-up Response Function (TRRF).Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/tw1D29dDxmY


Author(s):  
Marion Tissier ◽  
Jochem Dekkers ◽  
Ad Reniers ◽  
Stuart Pearson ◽  
Ap Van Dongeren

Several studies have reported the development of undular bores over fringing coral reefs (e.g, Gallagher, 1976; Nwogu and Demirbilek, 2010) but the importance of this phenomenon for reef hydrodynamics has never been studied. Yet, the transformation of a long wave (e.g., swell or infragravity wave) into an undular bore leads to significant modifications of the wave field. The formation of undulations is for example associated to a significant increase of the leading bore height. Moreover, if the undulations have enough time to develop (i.e. if the reef flat is wide enough), the initial long wave will ultimately split into a series of solitons (e.g., Grue et al., 2008). All this is likely to affect wave run-up. As reeffronted coastlines are particularly vulnerable to flooding, a good understanding of long wave transformation over the reef flat, including their possible transformation into undular bores, is crucial. In this study, we investigate undular bore development over reef-type profiles based on a series of laboratory experiments. More specifically, we aim to characterize the conditions under which undular bores develop, and analyse how their development affect the hydrodynamics at the toe of the reef-lined beach and the resulting wave run-up.


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