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 CHRONIC BEACH EROSION INDUCED BY COASTAL STRUCTURES IN CHELEM, YUCATÁN

2012 ◽  
Vol 1 (33) ◽  
pp. 125 ◽  
Author(s):  
María Alejandra Lira-Pantoja ◽  
Alec Torres-Freyermuth ◽  
Christian Mario Appendini ◽  
Diana Carolina Fernández ◽  
Paulo Salles ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Water Depth ◽  
Beach Erosion ◽  
Wave Transformation ◽  
Coastal Structures ◽  
Erosion Rates ◽  
Wave Conditions ◽  
Alongshore Sediment Transport ◽  
The Waves

The Yucatan coastline has been experiencing beach erosion during the past few decades; the erosion has reached critical points at some locations such as the Chelem beach, located near the Progreso Pier. Despite this problem, only few studies have been devoted in order to investigate the role of coastal structures on explaining the high erosion rates reported at this location. Therefore, the aim of this work is to evaluate the effects of the Progreso Pier on the wave transformation and alongshore sediment transport in the study area. Field surveys were conducted in a monthly basis in order to estimate the erosion rates and wave conditions with an ADCP installed at 8 m water depth. The field information confirmed the high erosional trends (O(1)m/year) that explain coastal infrastructure damage and property losses. The wave measurements were employed as the forcing of a wind-wave numerical model (MIKE 21 SW). The numerical model is implemented in the study area for two different scenarios, with and without the pier; this was to estimate nearshore wave conditions. Subsequently, the nearshore wave climate at 5 m water depth is employed for the calculation of alongshore sediment transport rates in 5 points that are representative of the littoral drift along the study area. The modeling results show that the pier acts as a large scale wave-sheltering structure that induces important alongshore sediment transport gradients under mean wave conditions, decreasing the capacity of the waves to recover the beach. On the other hand, during winter storms, when the direction of the waves is from the NNW, the structure does not seem to play an important role on wave transformation into the study. As a result, the Progreso Pier enhances beach erosion in the Chelem area by inducing algonshore gradients in sediment transport and decreasing the beach recovery capability

Modelling of Periodic and Random Wave Forces on Submarine Pipelines

2006 ◽  
Author(s):  
Francesco Aristodemo ◽  
Giuseppe R. Tomasicchio ◽  
Paolo Veltri
Keyword(s):  
Numerical Model ◽  
Laboratory Investigation ◽  
Time History ◽  
Hydrodynamic Forces ◽  
Random Wave ◽  
Wave Forces ◽  
Random Waves ◽  
Large Wave ◽  
Wave Flume ◽  
History Of

A numerical model for the prediction of the time variation of the flow field and the hydrodynamic forces on bottom submarine pipelines is proposed. The model is an extension for periodic and random waves of the Wake II hydrodynamic forces model (Soedigdo et al., 1999), originally proposed for sinusoidal waves. An extensive laboratory investigation has been carried out in order to calibrate the model. The numerical model is based on an analysis of the time history of the velocity field at each wave semi-cycle. A modified relationship of the wake velocity is introduced and the time history of the drag and lift hydrodynamic coefficients are obtained using a Gauss integration of the start-up function. The laboratory investigation was performed at the large wave flume of the Centro Sperimentale per Modelli Idraulici at Voltabarozzo (Padua, Italy). The tests were carried out by measuring the pressure values at 8 transducers mounted on a cylinder subjected to different periodic and random waves. The experiments refer to the range 4 ÷ 12 of the Keulegan-Carpenter number for periodic waves and to the range 4 ÷ 9 for random waves. The empirical parameters involved in the extended Wake II and in the classical Morison models were calibrated using the results of the sampled velocities and force time histories under different wave conditions. The comparisons between the experimental and numerical results indicate that the extended Wake II model allows an accurate evaluation of the peaks and of the phase shifts of the horizontal and vertical forces and is more accurate than the Morison model.

A numerical model for earthquake-induced hydrodynamic forces and wave forces on inclined circular cylinder

2020 ◽  
Vol 207 ◽  
pp. 107382 ◽  
Author(s):  
Piguang Wang ◽  
Xiaojing Wang ◽  
Mi Zhao ◽  
Xinglei Cheng ◽  
Xiuli Du
Keyword(s):  
Numerical Model ◽  
Circular Cylinder ◽  
Hydrodynamic Forces ◽  
Wave Forces

scholarly journals Wave interaction with Floating platform of different shapes and supports using BEM approach

2017 ◽  
Vol 14 (2) ◽  
pp. 115-133
Author(s):  
Anoop I. Shirkol ◽  
Nasar Thuvanismail
Keyword(s):  
Numerical Model ◽  
Elastic Plate ◽  
Wave Interaction ◽  
Wave Force ◽  
Ocean Waves ◽  
Wave Forces ◽  
Thin Elastic Plate ◽  
Floating Platform ◽  
Floating Elastic Plate ◽  
Different Shapes

Wave interaction with a floating thin elastic plate which can be used as floating platform is analyzed using Boundary Element Method (BEM) for different shapes such as rectangular, circular and triangular. Different support conditions are considered and the performance of the floating platform under the action of ocean waves is explored. The study is performed under the assumption of linearized water wave theory and the floating elastic plate is modelled based on the Euler-Bernoulli beam theory. Using Galerkin’s approach, a numerical model has been developed and the hydrodynamic loading on the floating elastic plate of shallow draft (thickness) is investigated. The wave forces are generated by the numerical model for the analysis of the floating plate. The resulting bending moment and optimal deflection due to encountering wave force is analysed. The present study will be helpful in design and analysis of the large floating platform in ocean waves.

SIMULATION OF WAVE DYNAMICS AND SCOURING NEAR COASTAL STRUCTURES BY A NUMERICAL MODEL

2003 ◽  
Author(s):  
Thanh Ca VU ◽  
Yoshimichi YAMAMOTO ◽  
Katsutoshi TANIMOTO ◽  
Junichi ARIMURA
Keyword(s):  
Numerical Model ◽  
Coastal Structures ◽  
Wave Dynamics

Numerical Modelling of Breaking Wave Interaction With a Group of Four Vertical Slender Cylinders in Square Arrangements

2016 ◽  
Author(s):  
Mayilvahanan Alagan Chella ◽  
Hans Bihs ◽  
Arun Kamath ◽  
Dag Myrhaug ◽  
Øivind Asgeir Arnsten
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Numerical Model ◽  
Numerical Modelling ◽  
Wave Interaction ◽  
Wave Force ◽  
Wave Forces ◽  
Breaking Wave ◽  
Square Configuration ◽  
Breaking Wave Forces

The main purpose of the study is to investigate the breaking wave interaction with a group of four circular cylinders. The physical process of wave breaking involves many parameters and an accurate numerical modelling of breaking waves and the interaction with a structure remain a challenge. In the present study, the open-source (Computational Fluid Dynamics) CFD model REEF3D is used to simulate the breaking wave interaction with the multiple cylinders. The numerical model is based on the incompressible Reynolds Averaged Navier-Stokes (RANS) equations, the level set method for the free surface and the k–ω model for turbulence. The model uses a 5th-order conservative finite difference WENO scheme for the convective discretization and a 3rd-order Runge-Kutta scheme for time discretization. The numerical model is validated with experimental data of large-scale experiments for the free surface elevation and the breaking wave force on a single cylinder. A good agreement is seen between the numerical results and experimental data. Two different configurations with four cylinders are examined: in-line square configuration and diamond square configuration. The breaking wave forces on each cylinder in the group are computed for the two cases and the results are compared with the breaking wave force on a single isolated cylinder. Further, the study investigates the water surface elevations and the free surface flow features around the cylinders. In general, the cylinders in both configurations experience the maximum forces lower than the maximum force on a single cylinder. The results of the present study show that the interference effects from the neighbouring cylinders in a group strongly influence the kinematics around and the breaking wave forces on them.

Tsunami-Like Wave Forces on an Elevated Coastal Structure: Effects of Flow Shielding and Channeling

2020 ◽  
Vol 146 (4) ◽  
pp. 04020021 ◽  
Author(s):  
Andrew O. Winter ◽  
Mohammad S. Alam ◽  
Krishnendu Shekhar ◽  
Michael R. Motley ◽  
Marc O. Eberhard ◽  
...  
Keyword(s):  
Wave Forces ◽  
Coastal Structure

Prediction of Water Wave Breaking Height and Depth Using ANFIS

2011 ◽  
Author(s):  
Ehsan Delavari ◽  
Ahmad Reza Mostafa Gharabaghi ◽  
Mohammad Reza Chenaghlou
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Fuzzy Inference System ◽  
Wave Breaking ◽  
Fuzzy Inference ◽  
Breaking Point ◽  
Empirical Equations ◽  
Anfis Model ◽  
Inference System ◽  
Semi Empirical

Wave height as well as water depth at the breaking point are two basic parameters which are necessary for studying coastal processes. In this paper, the application of Fuzzy Inference System (FIS) and Adaptive Neuro-Fuzzy Inference System (ANFIS) and semi-empirical models are investigated. The data sets used in this study are published laboratory data obtained from regular wave breaking on plane, impermeable slopes collected from 22 sources. Results indicate that the developed ANFIS model provides more accurate and reliable estimation of breaking wave height, compared to semi-empirical equations. However, some of semi-empirical equations provide better predictions of water depth at the breaking point compared to the ANFIS model.

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