scholarly journals Offshore disasters: wave forces on offshore and coastal structures due to Tsunamis

2009 ◽  
Author(s):  
A. R. Foroughi ◽  
W. Sleeman ◽  
R. Scott
Keyword(s):  
Wave Forces ◽  
Coastal Structures

scholarly journals EXPERIMENTAL MODELING OF WAVE FORCES AND HYDRODYNAMICS ON ELEVATED COASTAL STRUCTURES SUBJECT TO WAVES, SURGE OR TSUNAMIS: THE EFFECT OF BREAKING, SHIELDING AND DEBRIS

2018 ◽  
pp. 53
Author(s):  
Pedro Lomonaco ◽  
Mohammad Shafiqual Alam ◽  
Pedro Arduino ◽  
Andre Barbosa ◽  
Daniel T. Cox ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
Tsunami Wave ◽  
Coastal Communities ◽  
Accurate Estimation ◽  
Coastal Protection ◽  
Wave Forces ◽  
Coastal Structures ◽  
Critical Variable ◽  
Large Numbers ◽  
Recreational Services

Coastal communities provide important economic, transport, and recreational services to large numbers of people worldwide. However, these coastal communities are vulnerable to damage by extreme events such as tropical cyclones or tsunamis. Waves and surge, as well as tsunami-wave events, may cause extensive damage to elevated structures through a combination of horizontal and vertical wave and surge-induced forces. Structural elevation has been shown to be a critical variable affecting damage and loss. Recent efforts have been made to retrofit structures or improve coastal protection and damage mitigation plans in coastal communities to increase community resilience. However, to effectively retrofit old structures or design new structures to resist damage due to hurricanes or tsunamis, engineers require an accurate estimation of both the wave hydrodynamics and the resulting loads.

scholarly journals The Reproduction Ability of a Numerical Model for Simulating the Outflow Rate of Backfilling Materials from a Coastal Structure

2019 ◽  
Vol 7 (12) ◽  
pp. 447
Author(s):  
Kornvisith Silarom ◽  
Yoshimichi Yamamoto
Keyword(s):  
Numerical Model ◽  
Water Depth ◽  
Fluid Motion ◽  
Wave Forces ◽  
Empirical Equations ◽  
Coastal Structures ◽  
Large Wave ◽  
Coastal Structure ◽  
Outflow Rate ◽  
Shallow Area

In very shallow areas, the frequency by which coastal structures (like dikes and seawalls) are directly broken by large wave forces is low because large waves are broken in deeper areas. The main cause for such destruction is ground scour in front of the structures and outflow of backfilling materials by middle-scale waves; therefore, the scour and the outflow should be considered when designing a coastal structure in a very shallow area. In this paper, a numerical model consisting of CADMAS-SURF, which can calculate fluid motion in porous media, and empirical equations for simulating the outflow phenomena are introduced; thereafter, practical calculations on field cases in Thailand and Japan are demonstrated. Additionally, since the effects of wave periods and water depth to the outflow rate have never been clarified, hydraulic model experiments, empirical calculations using an existing formula, and numerical simulations are performed in order to examine these effects on the outflow rate. The simulated results using the numerical model align well with the experimental results. Moreover, both results show that the outflow rate is proportional to the wave period and inversely proportional to water depth.

scholarly journals AN EXPERIMENTAL STUDY OF A SOLITARY WAVE IMPACTING A VERTICAL SLENDER CYLINDER

2020 ◽  
pp. 8
Author(s):  
Bing Tai ◽  
Yuxiang Ma ◽  
Guohai Dong ◽  
Marc Perlin
Keyword(s):  
Solitary Wave ◽  
Structural Response ◽  
Equation Of Motion ◽  
Temporal Variations ◽  
Wave Forces ◽  
Wave Loads ◽  
Coastal Structures ◽  
High Wave ◽  
Wave Kinematics ◽  
Structural Responses

Solitary waves can evolve into plunging breakers during shoaling, inducing high wave loads on coastal structures. Meanwhile, plunging waves propagate with rapid spatial-temporal variations both in wave geometry and wave kinematics, causing varying forces on structures for different breaking stages (Chan et al., 1995). Although there have been numerous experiments for wave forces on cylinders, to our knowledge no experiments have studied the forces at different breaking stages of a plunging solitary wave. Thus, in our study, experiments are conducted to investigate the force due to a plunging solitary wave impacting a circular cylinder as a function of the wave's phase. Due to these forces, as expected structural responses are induced (Paulsen et al., 2019); to eliminate the effect of the structural response, the equation of motion is proposed to facilitate extracting only the isolated hydrodynamic forces.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/P07Cdlnxe7s

scholarly journals CFD Simulations of Multi-Directional Irregular Wave Interaction With a Large Cylinder

2018 ◽  
Author(s):  
Weizhi Wang ◽  
Arun Kamath ◽  
Hans Bihs
Keyword(s):  
Wave Field ◽  
Ocean Waves ◽  
Irregular Waves ◽  
Wave Forces ◽  
Good Prediction ◽  
Wave Steepness ◽  
Coastal Structures ◽  
Regular Waves ◽  
Irregular Wave ◽  
Large Cylinder

Ocean waves are random by nature and can be regarded as a superposition of a finite number of regular waves travelling in different directions with different frequencies and phases. Cylinder-shaped objects are commonly present in most coastal structures. An irregular bottom topography has a significant influence on the wave behaviours and therefore the wave forces on the coastal structures. A numerical approach that is able to calculate the wave forces on a cylinder in a multi-directional irregular wave field over an irregular bottom is desired. As Computational Fluid Dynamics (CFD) is able to represent most of the wave behaviour with few assumptions, it is considered to be an attractive option to address these issues. The open-source CFD wave model REEF3D has shown good performances in simulating wave propagation over irregular bottoms and a good prediction of wave forces on a cylinder in a uni-directional wave field, yet the ability to calculate the wave force in a multi-directional irregular sea needs to be validated. Therefore, this paper attempts to simulate the multi-directional random sea interaction with a large cylinder using REEF3D and validate the results. A novel approach of multi-directional irregular wave generation method in a CFD-based numerical wave tank is introduced. Only even-bottom tanks are considered in this study, leaving the irregular bottom simulation for future studies. Furthermore, among many factors that influence the wave forces, this paper focuses particularly on the effect of the wave steepness. The effects of wave steepness in regular waves, uni-directional irregular waves and multi-directional irregular waves are investigated. Goda’s JONSWAP frequency spectrum and the frequency-independent Mitsuyasu directional spreading function are used to generate the multi-directional irregular waves. The wave forces due to the multi-directional irregular waves in the numerical tank are compared with experimental data. The performance of the CFD simulation is analysed and discussed.

scholarly journals PHYSICAL AND NUMERICAL MODELLING OF THE FLOW STRUCTURE BEHIND STRUCTURE IN TSUNAMI-LIKE FLOW

2018 ◽  
pp. 17
Author(s):  
Hidenori Ishii ◽  
Tomoya Shibayama ◽  
Jacob Stolles
Keyword(s):  
Wave Force ◽  
Flow Fields ◽  
Shielding Effect ◽  
Structure Stability ◽  
Wave Forces ◽  
Coastal Structures ◽  
Three Dimensional Model ◽  
Vertical Column ◽  
Measured Velocity ◽  
Plane Flow

Coastal structures are expected to play a role as evacuation buildings. Numerous studies have been examined tsunami-induced wave force acting on an inland building (Shigihara et al., 2009; Arimitsu et al., 2014). In addition, coastal structures have the potential to obstruct inundating tsunami waves, protecting structure further from the coastline. Hydraulic experiments and numerical calculations on shielding effect are being carried out. Alternatively, the vortices from these structures can result in significant scour downstream, influencing downstream structure stability. In the 2011 Tohoku Region Pacific Offshore Earthquake, many cases were reported that the structure was scrubbed and the structure fallen down. Skakiyama et al. (2007) and Sakakiyma et al. (2008) pointed out that the standing vortex generated around the structure winds sand and causes scouring. Therefore, understanding the vortices generated around the structure is also important in predicting the scouring phenomenon. As such, the flow properties around coastal structures must be considered and acknowledged within the design process. However, there are a few studies focusing on the flow fields behind structure.Arnason et al. (2009) measured velocity fields of dam-break flow around/in the wake of a vertical column. Wei et al. (2015) reproduced the experiment performed using SPH. However, in the experiment, vortexes are not considered and the influence of the existence of structures on the surroundings has not been sufficiently considered. Therefore, in this study, the flow fields of a tsunami-like wave around structures were examined through hydraulic experiments. This experiment was performed to clarify the local vortex structure behind structures by measuring the plane flow velocity field. Also, the effect of obstructing protecting the land side structure is assessed by measuring the wave force behind structures. Furthermore, a three-dimensional model (OpenFOAM) was used to further analyze the flow, focusing on water-level and wave forces behind the structure.

scholarly journals DYNAMIC FORCES DUE TO WAVES BREAKING AT VERTICAL COASTAL STRUCTURES

1988 ◽  
Vol 1 (21) ◽  
pp. 186 ◽  
Author(s):  
Hans-Werner Partenscky
Keyword(s):  
Breaking Waves ◽  
Wave Forces ◽  
Test Results ◽  
Coastal Structures ◽  
Design Wave Height ◽  
Dynamic Forces ◽  
The Difference ◽  
Almost All ◽  
The Impact ◽  
Empirical Approaches

In the past 20 years, considerable effort has been devoted to replacing the widely used approaches of HIROI, MINIKIN, NAGAI, PLAKIDA and others /1,2,3,4/, for the design of vertical breakwaters under the impact of breaking waves, with improved and more exact calculation methods. However, almost all new theoretical and empirical approaches lacked the support of prototype measurements or test results from model measurements at a larger scale. The difference between the proposed design criteria and classical approaches is sometimes so great that engineers do not have a reliable method for the design of a vertical or composite breakwater. Figure 1 shows the resulting wave forces per unit width due to different theories as a function of the design wave height H.

Design wave loads for a jetty at Plymouth, Montserrat

1995 ◽  
Vol 22 (6) ◽  
pp. 1084-1091
Author(s):  
Michael Isaacson ◽  
Norman Allyn ◽  
Colleen Ackermann
Keyword(s):  
Wave Breaking ◽  
Wave Forces ◽  
Impact Loads ◽  
Wave Loads ◽  
Coastal Structures ◽  
Wave Impact ◽  
Wave Effects ◽  
Wave Shoaling ◽  
Inertia Forces ◽  
Hurricane Hugo

This paper describes the assessment of waves and wave effects with respect to the design of a jetty at Plymouth, Montserrat, in the eastern Caribbean Sea. A previous jetty was destroyed in 1989 by Hurricane Hugo, and a critical part of the new jetty's design relates to the effects of waves. Particular attention is given to the establishment of design wave conditions. This includes both hurricane and non-hurricane conditions and requires a consideration of wave shoaling and refraction, as well as wave breaking in the vicinity of the jetty. The prediction of design wave loads includes the calculation of drag and inertia forces and an assessment of impact loads due to waves on the underside of the jetty and waves breaking onto the deck. Key words: coastal engineering, coastal structures, hydrodynamics, wave forces, wave impact, waves.

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