scholarly journals PHYSICAL MODEL OF TSUNAMI-LOADS ON A SEASIDE BUILDING ARRAY

2020 ◽  
pp. 2
Author(s):  
Naoto Kihara ◽  
Taro Arikawa ◽  
Masashi Watanabe ◽  
Hideki Kaida ◽  
Fumiya Murase ◽  
...  
Keyword(s):  
Numerical Models ◽  
Benchmark Test ◽  
Tsunami Inundation ◽  
Wave Pressure ◽  
The Past ◽  
Inundation Depth ◽  
Benchmark Tests ◽  
Evaluation Models ◽  
Building Array ◽  
Debris Impact

The devastating damage to buildings and infrastructure caused by the 2011 Tohoku-oki earthquake and tsunami highlighted the importance of evaluating tsunami impacts in areas at risk of tsunami inundation for disaster prevention and mitigation. Evaluation technologies have been vigorously researched and developed over the past decade. A wide variety of numerical models exist that can potentially be applied to evaluate tsunami impacts. Furthermore, several either theoretical or empirical models to evaluate tsunami impacts, such as evaluation models of debris impact force and tsunami wave pressure, have been proposed. To validate these numerical and evaluation models, both experimental and theoretical benchmark tests have been conducted (e.g., Horrillo et al., 2015). Most of these tests have been conducted to validate models of tsunami generation, propagation, and inundation. However, the number of benchmark tests to validate tsunami loads are limited, and especially, those for complex terrains are rare. In this study, as a benchmark test to validate modeling of tsunami inundation and wave pressure, hydraulic experiments of tsunami inundations were conducted over a seaside area model, in which building arrays were installed. The inundation depth, velocity, and pressure were numerically predicted for the condition of the benchmark test, and then compared with the measured data for validation.

scholarly journals DEVELOPMENT OF TSUNAMI INUNDATION EVALUATION METHOD CONSIDERING DAMAGE LEVEL OF SEAWALL

2018 ◽  
pp. 77
Author(s):  
Katsumi Seki ◽  
Taro Arikawa ◽  
Kenichiro Shimosako ◽  
Tomohiro Takagawa ◽  
Yu Chida
Keyword(s):  
Numerical Simulation ◽  
Monte Carlo ◽  
Evaluation Method ◽  
Numerical Models ◽  
Destruction Process ◽  
Tsunami Inundation ◽  
Damage Level ◽  
Inundation Area ◽  
Inundation Depth ◽  
Subduction Zone Earthquake

Against the huge tsunami with the subduction-zone earthquake, structures such as breakwater and seawall are constructed. The expected effects of these structures are to reduce the inundation depth and inundation area. In other words, if we estimate tsunami inundation using numerical simulation accurately, it is necessary to reflect the situation of these structures in the numerical models. However in the present technology, it is difficult to predict while to estimate and reflect the destruction process by earthquake and tsunami attack. In this study, we assume that the damage level of structures are uncertain phenomenon and we develop that evaluated the tsunami inundation stochastically using Monte Carlo method.

scholarly journals Numerical Simulation of Tsunami Inundation in Urban Areas

2006 ◽  
Vol 1 (1) ◽  
pp. 148-156 ◽  
Author(s):  
Tetsuya Hiraishi ◽  
◽  
Tomohiro Yasuda ◽  
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Simulation Model ◽  
Urban Areas ◽  
Tokyo Bay ◽  
Tsunami Inundation ◽  
Model City ◽  
Inundation Depth ◽  
The Pacific ◽  
Potential Damage

The population and property in urban areas facing waterfronts is rapidly increasing together with the probability that a huge tsunami will occur on the Pacific Rim. The huge potential damage reflects the need to develop a highly accurate simulation model for tsunami inundation to help mitigate tsunami effects. We developed a simulation model to estimate the inundation depth and speed of tsunamis in urban areas. The model was applied to calculate the vari- ation of inundation areas in a model city facing Tokyo Bay. Experiments of tsunami inundation in the model city on a 1/50 scale was carried out for validation of the numerical model.

scholarly journals Anticorrelated observed and modeled trends in dissolved oceanic oxygen over the last 50 years

2012 ◽  
Vol 9 (4) ◽  
pp. 4595-4626 ◽  
Author(s):  
L. Stramma ◽  
A. Oschlies ◽  
S. Schmidtko
Keyword(s):  
Large Scale ◽  
Model Comparison ◽  
Numerical Models ◽  
Regional Patterns ◽  
The Past ◽  
Tropical Oceans ◽  
Model Configuration ◽  
Pattern Correlation ◽  
Increasing Trends ◽  
Global Mean

Abstract. Observations and model runs indicate trends in dissolved oxygen (DO) associated with current and ongoing global warming. However, a large-scale observation-to-model comparison has been missing and is presented here. This study presents a first global compilation of DO measurements covering the last 50 years. It shows declining upper-ocean DO levels in many regions, especially the tropical oceans, whereas areas with increasing trends are found in the subtropics and in some subpolar regions. For the Atlantic Ocean south of 20° N, the DO history could even be extended back to about 70 years, showing decreasing DO in the subtropical South Atlantic. The global mean DO trend between 50° S and 50° N at 300 dbar for the period 1960 to 2010 is −0.063 μmol kg−1 yr−1. Results of a numerical biogeochemical Earth system model reveal that the magnitude of the observed change is consistent with CO2-induced climate change. However, the correlation between simulated and observed patterns of past DO change is negative, indicating that the model does not correctly reproduce the processes responsible for observed regional oxygen changes in the past 50 years. A negative pattern correlation is also obtained for model configurations with particularly low and particularly high diapycnal mixing, for a configuration that assumes a CO2-induced enhancement of the C:N ratios of exported organic matter and irrespective of whether climatological or realistic winds from reanalysis products are used to force the model. Depending on the model configuration the 300 dbar DO trend between 50° S and 50° N is −0.026 to −0.046 μmol kg−1 yr−1. Although numerical models reproduce the overall sign and, to some extent, magnitude of observed ocean deoxygenation, this degree of realism does not necessarily apply to simulated regional patterns and the representation of processes involved in their generation. Further analysis of the processes that can explain the discrepancies between observed and modeled DO trends is required to better understand the climate sensitivity of oceanic oxygen fields and predict potential DO changes in the future.

8. Glaciers of the past

2018 ◽  
pp. 146-152
Author(s):  
David J. A. Evans
Keyword(s):  
Numerical Models ◽  
Ice Core ◽  
Three Dimensional ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Aerial Imagery ◽  
The Past ◽  
Glacial Landforms

To reconstruct the former extent and dynamics of ice sheets and glaciers requires a knowledge of process-form relationships that goes beyond individual landform types. Instead, glacial geomorphologists need to analyse large areas of glaciated terrain in a more holistic way, combining the whole range of glacial landforms and sediments to reconstruct glacier systems of the past, a subject now known as palaeoglaciology. ‘Glaciers of the past’ explains how the combination of aerial imagery and landform analysis is used in palaeoglaciological reconstruction. Increasingly powerful computers are making it possible to compile sophisticated numerical models that use our knowledge of glaciological processes and ice-core-derived palaeoclimate data to create three-dimensional glacier and ice sheet reconstructions.

Analysis of Global Stability, Anchor Spacing, and Support Cable Loads in Wire Mesh and Cable Net Slope Protection Systems

2005 ◽  
Vol 1913 (1) ◽  
pp. 205-213 ◽  
Author(s):  
Navaratnarajah Sasiharan ◽  
Balasingam Muhunthan ◽  
Shanzhi Shu ◽  
Thomas C. Badger
Keyword(s):  
Numerical Models ◽  
Wire Mesh ◽  
System Failures ◽  
Design Elements ◽  
The Past ◽  
Protection Systems ◽  
Vertical Support ◽  
Stability Of Slope ◽  
The Stability ◽  
Horizontal Support

Wire mesh and cable net slope protection have been in use for more than 50 years along North American highways to control rockfall on actively eroding slopes. The basic design of these systems is comparatively similar throughout North America. It consists of a top horizontal cable suspended by regularly spaced anchors, typically a perimeter or widely spaced grid of horizontal and vertical support cables, and double-twisted, hexagonal wire mesh laced to the support ropes. To date, the design of the slope protection systems has been based primarily on empirical methods, engineering judgment, and experience. Although these systems generally perform well, there is some consensus among geotechnical specialists that some elements in the system may be overdesigned or even unnecessary. In addition, system failures under a variety of loading conditions within the past few decades indicate that certain design elements may in fact be underdesigned for their desired application. Analytical and numerical models to evaluate the stability of slope protection systems are presented. The inclusion of interior horizontal support ropes in addition to the top horizontal rope does not reduce the stress within the mesh and accordingly provides no mechanical benefit. Results also show that the stresses on the vertical support rope are much smaller than the top horizontal support rope. Therefore, the vertical ropes do not need to be as strong as the top horizontal rope. Further, some useful design charts for the design of slope protection system are presented.

Numerical Study on Spatial Correlation Characteristics of Tsunami Inundation Depth

2020 ◽  
Author(s):  
Yo Fukutani
Keyword(s):  
Risk Assessment ◽  
Spatial Correlation ◽  
Numerical Study ◽  
Material Strength ◽  
Initial Water ◽  
Earthquake Parameters ◽  
Tsunami Inundation ◽  
Inundation Depth ◽  
Fault Parameters ◽  
Tsunami Risk

<p>For a probabilistic tsunami risk assessment of multiple sites, it is important to consider the spatial correlation between tsunami inundation depth and the sites because it affects the aggregated probability distribution of site damages. Various uncertainties such as ground motion, building response characteristics, and material strength are considered in the probabilistic seismic risk assessment. However, any research that evaluates the spatial correlation characteristics of tsunamis is yet to be reported. In this study, we evaluate the macro spatial correlation coefficient of the tsunami inundation depth according to the relative distance in the tsunami run-up region. We firstly constructed the fault parameters of the Sagami trough earthquake which has a large slip off the Kanto area in Japan. The moment magnitude of the earthquake is 8.7, and there are 6,149 small faults. Using the initial water level calculated from the earthquake parameters as input data, we solved the continuous equation and 2D linear long wave equation, targeting Zushi city, Kanagawa Prefecture. The maximum tsunami inundation depth was 8.71 m. We regressed the exponential function (<em>ρ(x) = aexp(bx) + cexp(dx)</em>) for the relationship between the distance from the coastline and the tsunami inundation depth. As a result, we obtained an evaluation formula with a relatively high accuracy. The coefficient were a = 0.4555, b = −0.1653, c = 0.5434, d = −0.007345 and the determination coefficient was 0.992. The results of this study can be used for a probabilistic tsunami risk assessment for multiple sites.</p>

Addressing the siphoning effect in new shunt designs by decoupling the activation pressure and the pressure gradient across the valve

2013 ◽  
Vol 11 (2) ◽  
pp. 181-187 ◽  
Author(s):  
Tobias A. Mattei ◽  
Martin Morris ◽  
Kathleen Nowak ◽  
Daniel Smith ◽  
Jeremy Yee ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Flow Rate ◽  
Fluid Velocity ◽  
Component System ◽  
The Past ◽  
Benchmark Tests ◽  
Final Design ◽  
Actual Flow Rate ◽  
Actual Flow ◽  
Labview Program

Object Although several improvements have been observed in the past few years in shunt technology, currently available systems still present several associated problems. Among these, overdrainage along with its complications remains one of the great challenges for new shunt designs. To address the so-called siphoning effect, the authors provide a practical example of how it is possible to decouple the activation pressure and the pressure gradient across the valve through a 3–key component system. In this new shunt design, the flow is expected to depend only on the intracranial pressure and not on the pressure gradient across the valve, thus avoiding the so-called siphoning effect. Methods The authors used computer models to theoretically evaluate the mechanical variables involved in the operation of the newly designed valve, such as the fluid's Reynolds number, proximal pressure, distal pressure, pressure gradient, actual flow rate, and expected flow rate. After fabrication of the first superscaled model, the authors performed benchmark tests to analyze the performance of the new shunt prototype, and the obtained data were compared with the results predicted by the previous mathematical models. Results The final design of the new paddle wheel valve with the 3–key component antisiphoning system was tested in the hydrodynamics laboratory to prove that the siphoning effect did not occur. According to the calculations obtained using the LabVIEW program during the experiments, each time the distal pressure decreased without an increase in the proximal pressure (despite the range of the pressure gradient), the pin blocked the spinning of the paddle wheels, and the calculated fluid velocity through the system tended to zero. Such a situation was significantly different from the expected flow rate for such a pressure gradient in a siphoning situation without the new antisiphon system. Conclusions The design of this new prototype with a 3–key component antisiphoning system demonstrated that it is possible to decouple the activation pressure and the pressure gradient across the valve, avoiding the siphoning effect. Although further developments are necessary to provide a model compatible to clinical use, the authors believe that this new prototype illustrates the possibility of successfully addressing the siphoning effect by using a simple 3–key component system that is able to decouple the activation pressure and the pressure gradient across the valve by using a separate pressure chamber. It is expected that such proof of concept may significantly contribute to future shunt designs attempting to address the problem of overdrainage due to the siphoning effect.

scholarly journals Review of Sand Production Prediction Models

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Hossein Rahmati ◽  
Mahshid Jafarpour ◽  
Saman Azadbakht ◽  
Alireza Nouri ◽  
Hans Vaziri ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Prediction Models ◽  
Numerical Models ◽  
Element Model ◽  
Reservoir Rock ◽  
Sand Production ◽  
The Past ◽  
Short Period ◽  
Analytical Formulae ◽  
The Continuum

Sand production in oil and gas wells can occur if fluid flow exceeds a certain threshold governed by factors such as consistency of the reservoir rock, stress state and the type of completion used around the well. The amount of solids can be less than a few grams per cubic meter of reservoir fluid, posing only minor problems, or a substantial amount over a short period of time, resulting in erosion and in some cases filling and blocking of the wellbore. This paper provides a review of selected approaches and models that have been developed for sanding prediction. Most of these models are based on the continuum assumption, while a few have recently been developed based on discrete element model. Some models are only capable of assessing the conditions that lead to the onset of sanding, while others are capable of making volumetric predictions. Some models use analytical formulae, particularly those for estimating the onset of sanding while others use numerical models, particularly in calculating sanding rate. Although major improvements have been achieved in the past decade, sanding tools are still unable to predict the sand mass and the rate of sanding for all field problems in a reliable form.

Accretion of continental crust: thermal and geochemical consequences

1981 ◽  
Vol 301 (1461) ◽  
pp. 347-357 ◽  
Keyword(s):  
Continental Crust ◽  
Numerical Models ◽  
Granulite Facies ◽  
Vapour Phase ◽  
Controlled Processes ◽  
Sialic Crust ◽  
Partial Melt ◽  
The Past ◽  
Profound Influence ◽  
Mineral Assemblages

The irreversible chemical differentiation of the Earth’s mantle to produce sialic crust over the past 3900 Ma has most probably occurred during widely separated, but short-lived, accretion episodes. These episodes involved the massive addition of juvenile sialic magma to the Earth’s surface, thickening pre-existing crust. Simple numerical simulations, based on tectonic, petrological and geochemical observations on Archaean high-grade orthogneiss terranes, have been used to explore the metamorphic and geochemical consequences of massive thickening of sialic crust during short-lived accretion episodes. The location of the main sites of magmatic addition within the crust exert a profound influence on the thermal régimes. Geochemical differentiation of the continental crust by partial-melt and vapour-phase-controlled processes, and the development of granulite facies mineral assemblages can be integrated with the simple numerical models. Finally, the survival of thick Archaean continental crust imples the contemporaneous stabilization of thick lithospheric substructures to the newly formed continental masses.

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