• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.2
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• pp.91-107
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• 1992

A numerical formulation is developed to solve the linear three-dimensional hydrodynamic equations which describes wind induced flows in a homogeneous shelf sea. The hydmdynamic equations are at the outset separated into two systems. namely, an equation containing the gradient of sea surface elevation and the mean flow (external mode) and an equation describing the deviation from the mean flow (internal mode). The Galerkin method is then applied to the internal mode equation. The eigenvalues are determined from the eigenvalue problem involving the vertical eddy viscosity subject to a homogeneous boundary condition at the surface and a sheared boundary condition at the sea bed. The model is tested in a one-dimensional channel with uniform depth under a steady, uniform wind. The analytical velocity profile by Cooper and Pearce (1977) using a constant vertical eddy viscosity in channels of infinite and finite length is chosen as a benchmark solution. The model is also tested in a homogeneous, rectangular basin with constant depth under a steady, uniform wind field (the Heaps' Basin of the North Sea scale).

• Journal of Environmental Science International
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• v.5 no.4
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• pp.453-462
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• 1996

This study was conducted to evaluate the level of atmospheric heavy metals and the relationship of that concentration with weather conditions. This research monitored the concentration of Total Suspended Particulates (TSP) at every three hours by using High Volume Air Sampler from December 24th, of 1995 to Febuary 20th, 1996 in Kimhae area, which recently became a rapidly growing residential and industrial sitc. The items such as air-temperature, relative humidity, radition, wind speed, and wind direction were monitored by using Atmospheric Weather System at the same time. From the collected TSP, the concentration of heavy metals were analyzed by using the Atomic Absorption Spcetrophotometry. The mean concentration of TSP was 110.4 $\mu\textrm{g}$/$m^3$, and the mean concentration of lead (Pb), copper(Cu), chromium (Cr), manganese (Mn), cadmium (Cd), were 0.837 $\mu\textrm{g}$/$m^3$, 0486 $\mu\textrm{g}$/$m^3$, 0.264$\mu\textrm{g}$/$m^3$). The concentration of Pb and Mn was higher in the moring and that of Cu, Cr and Cd was higher in the afternoon and the evening. Regarding the relationship between the concentration of pollutants and weather condition, the-concentration TSP revealed positive correlation with temperature, humidity, wind speed, but negative correlation with tradition (p<0.01). The concentration of Mn revealed positive correlation with temperature and humidity, but negative correlation with wind speed (p<0.01). And the the concentration of pollutants and weather condition revealed higher correlation within the same time period. In summary, the paralleled mornitoring of air conditions and weather condition should be recommended to. get the correct informations concerning the pollution and to prevent the deterioration of air conditions.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.183.3-183.3
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• 2010

This is the research of wind turbine that is designed to supply power to offshore buoy system. In order to reach maximum efficiency in limited space, vertical axis wind turbine was used. Vertical axis wind turbine system that was applied in this research has the form of lift and drag blade combined to achieve high efficiency at both high and low speed. In addition, support system was designed and developed to suit the offshore condition.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.184.1-184.1
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• 2010

Floating wind turbines have been suggested as a feasible solution for going further offshore into deeper waters. However, floating platforms cause additional unsteady motions induced by wind and wave conditions, so that it is difficult to predict annual energy output of wind turbines by using conventional power prediction method. That is because sectional inflow condition on a rotor plane is varied by unsteady motion of floating platforms. Therefore, aerodynamic simulation using Vortex Lattice Method(VLM) were used to investigate the influence of motion on the aerodynamic performance of a floating offshore wind turbine. Simulation with individual motion of offshore platform were compared to the case of onshore platform and carried out according to the wave height and the wave angular frequency.

• The KSFM Journal of Fluid Machinery
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• v.15 no.2
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• pp.63-68
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• 2012

This paper deals with the aerodynamic analysis and structural test under estimated loading condition for small composite blade, which is utilized in dual rotor wind turbine system. Firstly, the front and rear blades of dual rotor wind turbine system were modeled using reverse engineering method. And using finite volume method, the aerodynamic forces were analyzed at the rated and cutout wind speed to identify the pressure distribution on blades. And then, the full scale structural tests were conducted according to load and strength based methodology in IEC 61400-2 to identify the structural integrity of composite blade.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.29-30
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• 2007

This paper deals with effect of wind forces and moment acting on the training ship SAE NUR/. The results of drift angle and counter rudder angle due to wind effect are calculated by using the static equilibrium method especially with nonlinear mathematical expression, and then the critical wind velocity is found out. The given results am be applied directly to T/S SAE NURI in handling under the wind condition and used for merchant ships as a referential tool.

• Wind and Structures
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• v.30 no.3
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• pp.245-260
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• 2020

Wind load and responses are the major factors which govern the design norms of tall buildings. Corner modification is one of the most commonly used minor shape modification measure which significantly reduces the wind load and responses. This study presents a comparison of wind load and pressure distribution on different corner modified (chamfered and rounded) Y plan shaped buildings. The numerical study is done by ANSYS CFX. Two turbulence models, k-epsilon and Shear Stress Transport (SST), are used in the simulation of the building and the data are compared with the previous experimental results in a similar flow condition. The variation of the flow patterns, distribution of pressure over the surfaces, force and moment coefficients are evaluated and the results are represented graphically to understand the extent of nonconformities due to corner modifications. Rounded corner shape is proving out to be more efficient in comparing to chamfered corner for wind load reduction. The maximum reduction in the maximum force and moment coefficient is about 21.1% and 19.2% for 50% rounded corner cut.

• Wind and Structures
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• v.30 no.1
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• pp.29-35
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• 2020

This paper presents a comparative structural analysis of lattice hybrid tower with six legs with conventional tubular steel tower for an onshore wind turbine using finite element method. Usually a lattice hybrid tower will have a conventional industry standard 'L' profile section for the lattice construction with four legs. In this work, the researcher attempted to identify and analyze the strength of six legged lattice hybrid tower designed with a special profile instead of four legged L profile. And to compare the structural benefits of special star profile with the conventional tubular tower. Using Ansys, a commercial FEM software, both static and dynamic structural analyses were performed. A simplified finite element model that represents the wind turbine tower was created using Shell elements. An ultimate load condition was applied to check the stress level of the tower in the static analysis. For the dynamic analysis, the frequency extraction was performed in order to obtain the natural frequencies of the tower.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.1
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• pp.111-119
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• 2013

This paper present stabilization control of fixed speed wind generator by using variable speed permanent magnet wind generator in a wind farm connected with multi-machine power system. A novel direct-current based d-q vector control technique of back to back converter integrated with Fuzzy Logic Controller for optimal control configuration is proposed, in which both active and reactive powers delivered to a power grid system are controlled effectively. Simulation analyses have been performed using PSCAD/EMTDC. Simulation results show that the proposed control scheme is very effective to enhance the voltage stability of the wind farm during fault condition.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1152-1157
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• 2007

Anemometers to examine the characteristics of the natural wind in the vicinity of the railway track has been installed in two spots, one at the Cheon-Asan station of the Seoul-Busan high-speed line, and the other at the Daechon station of the Changhang conventional railway line in 2006 to examine the characteristics of the natural wind around the railway track to estimate the actual wind speed acting on the train and to develop the wind gust model consisting with the Korean climate condition. The measured data shows that the instant wind velocity frequently exceeds the velocity of train speed restriction, 20m/s, and the actual wind velocities measured in the vicinity of the track are larger than the that measured by the Korean Meteorological Administration(KMA) because the anemometers are installed on the highly-elevated bridges.