scholarly journals WAVE INTERACTION WITH SINGLE AND TWIN VERTICAL AND SLOPED SLOTTED WALLS

2018 ◽  
pp. 40
Author(s):  
Noor Al Anjari ◽  
Mohamad Al Khalidi ◽  
Subramaniam Neelamani
Keyword(s):  
Energy Dissipation ◽  
Wave Energy ◽  
Wave Reflection ◽  
Wave Interaction ◽  
Wave Structure ◽  
Wave Transmission ◽  
Random Wave ◽  
Wave Energy Dissipation ◽  
Structure Interaction ◽  
Wave Structure Interaction

The performance of single and twin slotted walls of varying porosity and slope angles is experimentally investigated, in order to understand the wave-structure interaction and to asses the characteristics of wave transmission, wave reflection, and wave energy dissipation under random wave conditions.

scholarly journals Wave Interaction with Single and Twin Vertical and Sloped Slotted Walls

2020 ◽  
Vol 8 (8) ◽  
pp. 589
Author(s):  
Mohamad Alkhalidi ◽  
Noor Alanjari ◽  
S. Neelamani
Keyword(s):  
Energy Dissipation ◽  
Transmission Coefficient ◽  
Wave Height ◽  
Wave Reflection ◽  
Wave Length ◽  
Wave Interaction ◽  
Wave Transmission ◽  
Random Wave ◽  
Dissipation Coefficient ◽  
Energy Dissipation Coefficient

The interaction between waves and slotted vertical walls was experimentally studied in this research to examine the performance of the structure in terms of wave transmission, reflection, and energy dissipation. Single and twin slotted barriers of different slopes and porosities were tested under random wave conditions. A parametric analysis was performed to understand the effect of wall porosity and slope, the number of walls, and the incoming relative wave height and period on the structure performance. The main focus of the study was on wave transmission, which is the main parameter required for coastal engineering applications. The results show that reducing wall porosity from 30% to 10% decreases the wave transmission by a maximum of 35.38% and 38.86% for single and twin walls, respectively, increases the wave reflection up to 47.6%, and increases the energy dissipation by up to 23.7% on average for single walls. For twin-walls, the reduction in wall porosity decreases the wave transmission up to 26.3%, increases the wave reflection up to 40.5%, and the energy dissipation by 13.3%. The addition of a second wall is more efficient in reducing the transmission coefficient than the other wall parameters. The reflection and the energy dissipation coefficients are more affected by the wall porosity than the wall slope or the existence of a second wall. The results show that as the relative wave height increases from 0.1284 to 0.2593, the transmission coefficient decreases by 21.2%, the reflection coefficient decreases by 15.5%, and the energy dissipation coefficient increases by 18.4% on average. Both the transmission and the reflection coefficients increase as the relative wave length increases while the energy dissipation coefficient decreases. The variation in the three coefficients is more significant in deep water than in shallower water.

scholarly journals To study impact level of dominat parameters and propose estimate methodology for wave transmission efficiency of unconventional complex pile submerged breakwater

2020 ◽  
Vol 19 (4) ◽  
pp. 611-625
Author(s):  
Nguyen Anh Tien
Keyword(s):  
Energy Dissipation ◽  
Wave Energy ◽  
Complex Structure ◽  
Transmission Efficiency ◽  
Wave Transmission ◽  
Random Wave ◽  
Submerged Breakwater ◽  
Dissipation Process ◽  
Wave Energy Dissipation ◽  
Major Factors

This article proposes semi-empirical equations to estimate wave transmission coefficient through submerged complex with solid pile breakwater based on theories of random wave energy conservation of perpendicular wave transmission incorporated with physical hydraulic experiments in wave flume applied on both types of submerged breakwater with and without piles. These equations are able to describe interactions and energy dissipation process for each element of this complex structure which are foundation block and pile rows. Energy dissipation process depends on three major factors which are [relative submerge depth (Rc/Hm0), relative crest width (B/Hm0), wave slope at construction location (sm=Hm0/Lm)] and wave energy dissipation process through pile rows is determined by two major factors [relative submerged depth or submerged length of piles (Rc/Hm0), relative pile row width (Xb/Lm)].

scholarly journals Investigation of Higher-Harmonic Wave Forces and Ringing Using CFD Simulations

2018 ◽  
Author(s):  
Arun Kamath ◽  
Hans Bihs ◽  
Csaba Pakozdi
Keyword(s):  
Structural Response ◽  
Vertical Cylinder ◽  
Wave Interaction ◽  
Wave Structure ◽  
Higher Order ◽  
Wave Forces ◽  
Numerical Wave Tank ◽  
Cfd Model ◽  
Structure Interaction ◽  
Wave Structure Interaction

Typical offshore structures are designed as tension-leg platforms or gravity based structures with cylindrical substructures. The interaction of waves with the vertical cylinders in high sea states can result in a resonant response called ringing. Here, the frequency of the structural response is close to the natural frequency of the structure itself and leads to large amplitude motions. This is a case of extreme wave loading in high sea states. This understanding of higher-order wave forces in extreme sea states is an essential parameter for obtaining a safe, reliable and economical design of an offshore structure. The study of such higher-order effects needs detailed near-field modelling of the wave-structure interaction and the associated flow phenomena. In such cases, a Computational Fluid Dynamics (CFD) model that can accurately represent the free surface and further the wave-structure interaction problem can provide important insights into the wave hydrodynamics and the structural response. In this paper, the open source CFD model REEF3D is used to simulate wave interaction with a vertical cylinder and the wave forces on the cylinder are calculated. The harmonic components of the wave force are analysed. The model employs higher-order discretisation schemes such as a fifth-order WENO scheme for convection discretisation and a third-order Runge-Kutta scheme for time advancement on a staggered Cartesian grid. The level set method is used to obtain the free surface, providing a sharp interface between air and water. The relaxation method is used to generate and absorb the waves at the two ends of the numerical wave tank. This method provides good quality wave generation and also the wave reflected from the cylinder are absorbed at the wave generation zone. In this way, the generated waves are not affected by the wave interaction process in the numerical wave tank. This is very essential in the studies of higher-order wave interaction problems which are very sensitive to the incident wave characteristics. The numerical results are compared to experimental results for higher-order forces on a vertical cylinder to validate the numerical model.

Assessment of random wave energy dissipation due to submerged aquatic plants in shallow water using deep water wave conditions

2021 ◽  
pp. 147509022110399
Author(s):  
Dag Myrhaug ◽  
Pierre-Yves Henry
Keyword(s):  
Energy Dissipation ◽  
Shallow Water ◽  
Deep Water ◽  
Aquatic Plants ◽  
Wave Energy ◽  
Water Wave ◽  
Random Wave ◽  
Wave Energy Dissipation ◽  
Submerged Aquatic Plants ◽  
Deep Water Wave

This article addresses the random wave energy dissipation due to submerged aquatic plants in shallow water based on deep water wave conditions including estimation of wave damping. The motivation is to provide a simple engineering tool suitable to use when assessing random wave damping due to small patches of plants in shallow water. Examples of application for typical field conditions are provided. The present method versus common practice is discussed. A possible application of the outcome of this study is that it can be used as a parameterization of wave energy dissipation due to vegetation patches of limited size in operational estuarine and coastal circulation models.

scholarly journals UPDATE OF THE EUROTOP NEURAL NETWORK TOOL: IMPROVED PREDICTION OF WAVE OVERTOPPING

2017 ◽  
pp. 2
Author(s):  
Barbara Zanuttigh ◽  
Sara Mizar Formentin ◽  
Jentsje Wouter Van der Meer
Keyword(s):  
Wave Reflection ◽  
Extreme Values ◽  
Wave Structure ◽  
The Internet ◽  
Reflection Coefficients ◽  
Wave Overtopping ◽  
Structure Interaction ◽  
Interaction Processes ◽  
The Mean ◽  
Wave Structure Interaction

The goal of this work is to present a synthesis of the improvements and updates developed to deliver the final version of the ANN tool adopted by the second edition of the wave overtopping manual, EurOtop, released on the internet in 2016. This tool consists of three identical but independent ANNs able to predict the main parameters representative of the wave-structure interaction processes, i.e. the mean wave overtopping discharge, the wave transmission and the wave reflection coefficients. The contribution focuses on the modifications of the ANN architecture carried out since the last ICCE conference to achieve an optimized representation of the wave overtopping, especially in case of low and extreme values of the overtopping discharge. The consistency of the ANN predictions is assessed through an artificial dataset including geometrical and climate input parameters that are varied with continuity, while the robustness of the tool is checked by applying the ANN to selected geometries excluded from the training database.

A New Coupled Model for the Assessment of Offshore Structures in Non-Gaussian Seas

2020 ◽  
Author(s):  
Griet Decorte ◽  
Alessandro Toffoli ◽  
Geert Lombaert ◽  
Jaak Monbaliu
Keyword(s):  
Coupled Model ◽  
Wave Interaction ◽  
Wave Structure ◽  
Offshore Structures ◽  
Higher Order ◽  
Structure Interaction ◽  
Cfd Models ◽  
Non Gaussian ◽  
Wave Structure Interaction ◽  
Interaction Phenomena

Abstract Although wave-wave interaction phenomena in random seas have shown to lead to a departure from Gaussian statistics and therefore to a higher occurrence of extreme waves, they are usually not taken along in the assessment of the dynamic behaviour of offshore structures. Supported by a rapid increase of computational resources, the use of Computational Fluid Dynamics (CFD) models has become viable for studying the above mentioned wave-structure interaction phenomena. Still, these models remain computationally expensive, which impedes their use for the large domains and the long periods of time necessary for studying non-Gaussian seas. Therefore, a one-way domain decomposition strategy is proposed, which takes advantage of the recent advances in CFD as well as of the computational benefits of the higher-order spectral (HOS) models previously used to assess non-Gaussian seas. The unidirectional non-Gaussian sea obtained by this coupled HOS-CFD model shows excellent agreement with the target wave field generated by the higher-order spectral numerical wave tank. In addition, the wave-structure interaction for a simplified monopile, which is excited by a non-Gaussian sea, seems to be captured well.

scholarly journals Investigation of a Stochastic Inverse Method to Estimate an External Force: Applications to a Wave-Structure Interaction

2012 ◽  
Vol 2012 ◽  
pp. 1-25 ◽  
Author(s):  
S. L. Han ◽  
Takeshi Kinoshita
Keyword(s):  
External Force ◽  
Inverse Method ◽  
Inverse Function ◽  
Wave Structure ◽  
Dynamic Responses ◽  
Structure Interaction ◽  
External Forces ◽  
Interaction Problem ◽  
Wave Structure Interaction

The determination of an external force is a very important task for the purpose of control, monitoring, and analysis of damages on structural system. This paper studies a stochastic inverse method that can be used for determining external forces acting on a nonlinear vibrating system. For the purpose of estimation, a stochastic inverse function is formulated to link an unknown external force to an observable quantity. The external force is then estimated from measurements of dynamic responses through the formulated stochastic inverse model. The applicability of the proposed method was verified with numerical examples and laboratory tests concerning the wave-structure interaction problem. The results showed that the proposed method is reliable to estimate the external force acting on a nonlinear system.

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