Reflection of oblique ocean water waves by a vertical rectangular porous structure placed on an elevated horizontal bottom

2014 ◽  
Vol 82 ◽  
pp. 135-143 ◽  
Author(s):  
S. Das ◽  
S.N. Bora
Author(s):  
John T. Imamura ◽  
Alaa Mansour

This paper proposes a design concept in the area of overtopping ocean wave energy devices. Current models of overtopping devices are limited to locations which experience large wave activity. The high energy associated with large waves enables the ocean water waves to overtop the device ramp into the collection reservoir which discharges through a power generating turbine. The ramp height is necessarily large to establish a sufficient collection reservoir head. The proposed design concept can utilize small waves by implementing a gearing system which can transfer water to the collection reservoir. This allows for greater access to the wave energy resource at more locations than currently possible. A simplified model of this design concept is presented and applied to varying wave conditions off the coast of California.


2020 ◽  
Author(s):  
Souheil Ezzedine ◽  
Luke Oman ◽  
David Dearborn ◽  
Paul Miller ◽  
Megan Syal

<p>Despite that the annual probability of an asteroid impact on earth is low, but over time, such catastrophic events are inevitable and can have negative global consequences. Several institutions around the world have come together to address global consequences of asteroids impacting earth. For example, interest in assessing the tsunami generation and impact consequences has led us to develop a physics-based framework to seamlessly simulate the event from source (asteroid entry) to ocean impact (splash) to long wave generation, propagation, and their catastrophic risk to people and infrastructure in coastal regions such inundation of the shoreline. The non-linear effects of the asteroid impact on the ocean surface are simulated using the hydrocode GEODYN to create the impact source for the shallow water wave propagation code, SWWP. The GEODYN-SWWP coupling is based on the structured adaptive mesh refinement infrastructure; SAMRAI developed at LLNL. Another consequence of ocean impact is the potentially global effects of an event that would otherwise be of only regional or local importance, should it occur on land. Only a fraction of the total impact energy is converted into water waves that have the ability to globally propagate in the oceans. The remaining energy is consumed by the “evaporation” of the asteroid, the ocean water being transformed into vapor and mist and the fractionization of ocean water and vapor into chlorine and bromine which alter the atmospheric chemistry, therefore impacting globally the Ozone layer and earth temperature. In this paper, we present our scheme of creating the source -- including nonlinear transient cratering and nearfield waves, generating the vapor cloud and the chemical speciation source load of chlorine and bromine to assess the global circulation of those plumes and their effects on the climate. We also present our coupling scheme of the hydrodynamic source using GEODYN with the global atmospheric circulation code GEOSCCM and illustrate the scheme on the PDC 2017 and PDC 2019 asteroid impact scenarios. We illustrate the coupling scheme for asteroids impact along the US, Europe and Asia shorelines. We illustrate, by examples, how the predictions of these numerical tools can help international, state and local government agencies reduce the risks and prepare and implement a  response and recovery plan.  This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.</p>


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liang Yang ◽  
Andrew Buchan ◽  
Dimitrios Pavlidis ◽  
Alan Jones ◽  
Paul Smith ◽  
...  

Purpose This paper aims to propose a three-phase interpenetrating continua model for the numerical simulation of water waves and porous structure interaction. Design/methodology/approach In contrast with one-fluid formulation or multi-component methods, each phase has its own characteristics, density, velocity, etc., and each point is occupied by all phases. First, the porous structure is modelled as a phase of continua with a penalty force adding on the momentum equation, so the conservation of mass is guaranteed without source terms. Second, the adaptive unstructured mesh modelling with P1DG-P1 elements is used here to decrease the total number of degree of freedom maintaining the same order of accuracy. Findings Several benchmark problems are used to validate the model, which includes the Darcy flow, classical collapse of water column and water column with a porous structure. The interpenetrating continua model is a suitable approach for water wave and porous structure interaction problem. Originality/value The interpenetrating continua model is first applied for the water wave and porous structure interaction problem. First, the structure is modelled as phase of non-viscous fluid with penalty force, so the break of the porous structure, porosity changes can be easily embedded for further complex studies. Second, the mass conservation of fluids is automatically satisfied without special treatment. Finally, adaptive anisotropic mesh in space is employed to reduce the computational cost.


2020 ◽  
Vol 218 ◽  
pp. 108159
Author(s):  
Guohai Dong ◽  
Xiang Gao ◽  
Xiaozhou Ma ◽  
Yuxiang Ma

1960 ◽  
Vol 9 (3) ◽  
pp. 430-444 ◽  
Author(s):  
E. V. Laitone

The expansion method introduced by Friedrichs (1948) for the systematic development of shallow-water theory for water waves of large wavelength was used by Keller (1948) to obtain the first approximation for the finite-amplitude solitary wave of Boussinesq (1872) and Rayleigh (1876), as well as for periodic waves of permanent type, corresponding to the cnoidal waves of Korteweg & de Vries (1895).The present investigation extends Friedrich's method so as to include terms up to the fourth order from shallow-water theory for a flat horizontal bottom, and thereby obtains the complete second approximations to both cnoidal and solitary waves. These second approximations show that, unlike the first approximation, the vertical motions cannot be considered as negligible, and that the pressure variation is no longer hydrostatic.


1975 ◽  
Vol 70 (4) ◽  
pp. 663-671 ◽  
Author(s):  
G. Keady ◽  
J. Norbury

Steady plane periodic waves on the surface of an ideal liquid above a horizontal bottom are considered. The flow is irrotational. LetQdenote the volume flow rate,Rthe total head andSthe flow force for the wave train. Bounds on wave properties are obtained in terms of the properties of (i) the conjugate streams with the sameQandR, and (ii) the conjugate streams with the sameQandS.


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