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In underwater wireless optical communications (UWOC), impulse response is important to characterize channel properties. In this paper, we consider the impulse response for UWOC multiple-input single-output (MISO) links with a uniform circular array (UCA) of light sources. The Monte Carlo approach is adopted to achieve the impulse response of UWOC MISO links for the turbid water environment. We propose...
Intensive cultures of shrimps produce more than 10 individuals per square meters with the use of hatchery reared post-larvae and the supply of compounded diets. The paddle wheel aerators are usually installed in the pond to supply oxygen and collect the sludge generated from the excretion of shrimps and the rest of the compounded food. The operation of paddlewheel aerators consume plenty of oil or...
An underwater wireless sensor network (UWSN) has multiple functions in ocean survey. A kind of UWSN has been proposed by Zhejiang University. In this paper the CFD method is utilized to verify the ability of a node to adjust its posture in deploying and recovering process. The minimum depth and the minimum time for a node to adjust itself to vertical were obtained in different initial inclined angles...
In this study we try to identify the thermal dispersion characteristics of coastal waters to consider their physical properties using a field observation and a three-dimensional numerical modeling with CFD (Computational Fluid Dynamics). A plume model and observed CTD data was used to predict the mixing behavior of thermal discharges in coastal waters of Tarawa, Kiribati. The elevation, current, temperature...
Research on the influence of specific hydrological environment change on current velocity and water exchange has a long history in oceanography; however, the majority of previous work has been based on traditional ocean models such as POM and FVCOM. This paper presents a stable joint method that combines a support vector machine with a hydrological model to predict current velocity in different hydrological...
In this article we present an approach to the description of Magnetohydrodynamic Propulsion. Preliminarly, an analytical model which includes an electromagnetic model and a thermal model is presented. Successively, in order to move beyond the analytical model, a 3-D MHD modeling tool and a Runge Kutta method based solver are presented and they are used to investigate an alternative MHD solutions....
Damutu Bay in eastern Zhejiang, China has abundant tidal flat resources for years of silt deposition in the wide open seas, making it an ideal place for mudflat reclamation. In this study we set up a two-dimensional hydrodynamic and sediment transport model based on Mike 21 FM to investigate changes in suspended sediment concentration (SSC) after reclaiming to 1 m and 3 m depth contours in the seas...
In response to the growing energy needs and the global trend on renewable energy development, we are also dedicated to harvesting marine energy from Kuroshio Current, which flows through the eastern waters of Taiwan. However, due to the lack of the offshore technological experience of constructing and deploying floating turbines with permanent mooring system in deep water, the deployment and recovery...
Sediment transport at the Yellow river delta is affected by many different factors, including tide, waves and river flows. With the change of river exit in 1996, a new delta is rapidly growing which leads to a new sediment transport regime. Most existing computer modelling work at the site is yet to take such changes into account. In addition, the wave action at the river mouth is often ignored in...
The aim of this study is to conduct a hydrodynamic analysis of a point absorber-type floating hemisphere with Power take-off(PTO) system for an optimum design of wave energy converter(WEC). In general, to predict the behavior of WEC, the equation of floating body motion can be solved in the frequency-domain analysis. A numerical model of PTO system is usually expressed as a linear damper-spring type...
Tidal stream offers divinable and regular electricity generation at higher power densities than other renewable energy sources. With an increasing concern over the potential of harnessing ocean energy for electricity generation by marine current turbine (MCT) and its impact on water environment, the exploration and assessment works are required. Based on a three-dimensional ocean model with a developed...
We examined characteristics of material transport and a tidal front formation in a semi-enclosed bay, Korea, based on numerical experiment results. Pollutant diffusion resulted in a relatively high concentration in the northwest part of the bay compared to the other area, because of inactive flow and topographic factor. The diffusion area of pollutant appeared 3.25km2 in the spring, 4.62km2 in the...
Model-based passive source localization is known to be quite sensitive to model mismatch. In this paper, we present a new implementation based on matched-mode processing. Specifically we formulate mode filtering as a convex optimization problem, and ℓ1-regularized least squares is applied, which is robust in terms of the numerical implementation. Simulations with respective full-depth and partially-spanned...
From field data of the Kuroshio Current near Miyake Island, the shear flow profile is discovered. To study its hydrodynamic effect, a nearly linear shear flow was obtained in a circulating tank by inserting grids of parallel rods with varying spacing. The results of the circulating tank test on an 880mm diameter model of a marine current turbine in the shear flow generated are presented. The experimental...
The proliferation of data coming in daily from ocean remote sensing observational networks is getting bigger and will likely to get a lot bigger. This fact makes it natural to search for methods and strategies that can make the best use of this wealth of information. In this work, we investigate the utility of historical datasets to missing data interpolation issues. We state missing data interpolation...
The effect of stanchion and reverse flow on turbine power performance is studied based on Computational Fluid Dynamics (CFD). The turbine in this paper is developed by National Ocean Technology Center (NOTC), the experiment study has been carried out in year 2014. The simulation model is validated based on experimental results. The CFD model can simulate the marine current conditions up to an acceptable...
Nearshore wave model was established based on the enhanced Boussinesq equations, which were dispersed into orthogonal grids on spatial distribution and solved using alternating direction implicit (ADI) algorithm. There are three kind of boundary conditions which are absorbing boundary, reflecting boundary and wave-generating boundary in the model, while the wave on open boundary was driven by the...
Precise and efficient numerical simulation of tracer transport processes in the marine environment is critical for environmental problems. Particle tracking method has the advantages over Eulerian method by overcome the problem of numerical diffusion but the concentration from typical particle tracking methods is affected by the number of particles used and the size of the volume cell. DREAM model...
When tsunami occurs and approaches land, wave heights in tens of meters can be generated and their destructive power could be enormous as shown in the 2011 earthquake off the Pacific coast of Tohoku, Japan. Most of the damages, such as inland flooding and destruction of structures, by tsunami are closely related to wave run-up near shoreline and its impact on the structures. However, it is not so...
The first and a crucial step in development of tidal current power is to make a comprehensive assessment at potential sites. In order to obtain the features of tidal current and properly site tidal current energy converter, the Regional Ocean Modeling System (ROMS) was employed to simulate tidal current in this region. Favorable comparison with the previous research indicates that this model has essential...
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