• Journal of Industrial Technology
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• v.28 no.B
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• pp.199-207
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• 2008

A linear wind prediction program, WAsP, was employed to predict wind speed at two different sites located in complex terrain in South Korea. The reference data obtained at locations more than 7 kilometers away from the prediction sites were used for prediction. The predictions from the linear model were compared with the measured data at the two prediction sites. Two compensation methods such as a self-prediction error method and a delta ruggedness index (RIX) method were used to improve the wind speed prediction from WAsP and showed a good possibility. The wind speed prediction errors reached within 3.5 % with the self prediction error method, and within 10% with the delta RIX method. The self prediction error method can be used as a compensation method to reduce the wind speed prediction error in WAsP.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.268-273
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• 2008

A linear wind prediction program, WAsP, was employed to predict wind speed at two different sites located in complex terrain in South Korea. The reference data obtained at locations more than 7 kilometers away from the prediction sites were used for prediction. The predictions from the linear model were compared with the measured data at the two prediction sites. Two compensation methods such as a self-prediction error method and a delta ruggedness index (RIX) method were used to improve the wind speed prediction from WAsP and showed a good possibility. The wind speed prediction errors reached within 3.5 % with the self prediction error method, and within 10% with the delta RIX method. The self prediction error method can be used as a compensation method to reduce the wind speed prediction error in WAsP.

• Journal of Environmental Science International
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• v.8 no.5
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• pp.555-558
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• 1999

A sea/land breeze circulation system and a regional scale circulation system are formed at a region which has complex terrain around coastal area and affect to the dispersion and advection of air pollutants. Therefore, it is important that atmospheric circulation model should be well designed for the simulation of regional dispersion of air pollutants. For this, Local Circulation Model, LCM which has an ability of high resolution is used. To verify the propriety of a LCM, we compared the simulation result of LCM with an exact solution of a linear theory over a simple topography. Since they presented almost the same value and pattern of a vertical velocity at the level of 1 km, we had a reliance of a LCM. For the prediction of dispersion and advection of air pollutants, the wind filed should be calculated with high accuracy. A numerical simulation using LCM will provide more accurate results over a complex terrain around coastal area.

• Wind and Structures
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• v.30 no.6
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• pp.547-558
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• 2020

With the development of economy and construction technology, more and more bridges are built in complex mountainous areas. Accurate assessment of wind parameters is important in bridge construction at complex terrain. In order to investigate the wind characteristics in the high-altitude difference area, a complex mountain terrain model with the scale of 1:2000 was built. By using the method of wind tunnel tests, the study of wind characteristics including mean wind characteristics and turbulence characteristics was carried out. The results show: The wind direction is affected significant by the topography, the dominant wind direction is usually parallel to the river. Due to the sheltering effect of the mountain near the bridge, the wind speed and wind attack angle along the bridge are both uneven which is different from that at flat terrain. In addition, different from flat terrain, the wind attack angle is mostly negative. The wind profiles obey exponential law and logarithmic law. And the fitting coefficient is consistent with the code which means that it is feasible to use the method of wind tunnel test to simulate complex terrain. As for turbulence characteristics, the turbulence intensity is also related to the topography. Increases sheltering effect of mountain increases the degree of breaking up the large-scale vortices, thereby increasing the turbulence intensity. Also, the value of turbulence intensity ratio is different from the recommended values in the code. The conclusions of this study can provide basis for further wind resistance design of the bridge.

• Wind and Structures
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• v.38 no.4
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• pp.231-244
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• 2024

As wind farms expand into low wind speed areas, an increasing number are being established in mountainous regions. To fully utilize wind energy resources, it is essential to understand the details of mountain flow fields. Reconstructing the wind speed field in complex terrain is crucial for planning, designing, operation of wind farms, which impacts the wind farm's profits throughout its life cycle. Currently, wind speed reconstruction is primarily achieved through physical and machine learning methods. However, physical methods often require significant computational costs. Therefore, we propose a Full Convolutional Neural Network (FCNN)-based reconstruction method for mountain wind velocity fields to evaluate wind resources more accurately and efficiently. This method establishes the mapping relation between terrain, wind angle, height, and corresponding velocity fields of three velocity components within a specific terrain range. Guided by this mapping relation, wind velocity fields of three components at different terrains, wind angles, and heights can be generated. The effectiveness of this method was demonstrated by reconstructing the wind speed field of complex terrain in Beijing.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.10
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• pp.499-506
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• 2001

Terrain Following means that a mobile object, such a user's avatar, must follow terrain, remaining in contact with the ground at all times in virtual environments. This makes a virtual environment have the effects of gravity. Terrain Following is often done using collision detection: however this is inefficient, because general collision detection solves a problem that is inherently more complex than merely determining terrain contact points. Many virtual environments avoid the expense by utilizing a flat terrain with a constant altitude everywhere. This makes a terrain following trivial, but lacks realism. This paper provides as algorithm and a data structure for a terrain following using a neighboring area search as a way to search neighboring polygons. Because this algorithm uses a pre-processing step that stores the terrain polygons for calculating, it results in reducing overheads to workstations that is used to construct and maintain a virtual environment. Consequently, workstation can be used to apply not only a terrain following but also other things.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.6
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• pp.827-841
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• 1999

The air quality simulation models in wide use for air quality impact assessmetns are reviewed. After an intensive survey and comparative study upon the environmental impact assessment reports submitted to Ministry of Environment during 1990~1998, we could identify the major common problems with the air quality impact assessment procedures. Several remedies are presented here, including use of the screening models applicable to the complex terrain.

• International Journal of CAD/CAM
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• v.8 no.1
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• pp.37-40
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• 2009

Based on the study of Digital Elevation Simplification Model and fractal theory, this paper put forward a new method to simulate complex terrain. That use simplified DEM data to construct terrain frame based on the quad tree at first, and then use fractal to generate the details of every node of the tree. In the process of construction, the LOD theory is used to simplify the terrain and get its typical data. According to the change of view position and direction, the paper gives a new way to judge the visibility of the surface patch. Experimental results show that this algorithm is simple, efficient and supports the real time dynamic simulation of terrain model.

• Journal of Environmental Science International
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• v.10 no.5
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• pp.343-350
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• 2001

To investigate air quality away from the coastal urban source region, we used a hybrid Eulerian - Lagrangian method which can describe the formation, transport, transform and deposition processes in complex terrain, with inclusion of shipping sources that were considered to be important emission in the coastal urban region. The result of the Eulerian advection - diffusion prediction was quite similar to that of the Lagrangian particle diffusion prediction. It showed that pollutants emitted from Sasang and Janglim industrial complexes can affect Hwamyeong and the coastal, respectively. During the daytime the concentration was low due to large deposition flux and terrain effect.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.6
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• pp.643-650
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• 1998

Many atmospheric dispersion models have been based on the Gaussian distribution concept of plume spread. In application of Gaussian plume dispersion models, vertical dispersion coefficient 3 has been known as a sensitive variable. Vertical diffusivity K2 (=Oz2/2t) tends to increase with surface roughness, and the value of K3 in urban area is larger than that in rural area due to heat emission as well as increased roughness. Though Pasquill proposed a modification scheme for qz vs x system of Pasquill-Gifford under consideration of roughness effect in 1976, there appears not to be realistic reexamination on the modification scheme. In this study literature review on the effect of terrain or roughness on venical plume dispersion has been carried out in order to improve the prediction results of atmospheric pollution concentration. Again a few research objectives on vertical atmospheric dispersion in complex terrain were Proposed.