• Journal of architectural history
• /
• v.7 no.2 s.15
• /
• pp.49-62
• /
• 1998

The character of spatial organization in rtaditional house is found through the analysis of field survey and measure of its micro climate in hot weather period of summer. The mean temperature of interior space is higher than outside space of the house. In the point of structural conditions, inside of Choga in caustal and mountain area is cooler than any other houses. In inland area, slate roof house is cooler than Choga. In mountain area, the thermal difference of inside and outside in Kyubjib is higher than Hotjib. In the point of spatial conditions, kitchen is the coolest space and very suitable for spatial organization. Anbang is the hottest space because of its centeral position in the house. In wind condition, mountain area is windy and caustal area is calm. Around the house the rear side of the house is windy and left side is calm.

• Atmosphere
• /
• v.16 no.4
• /
• pp.359-370
• /
• 2006

Terrain height variance spectra for the Korean mountain region are calculated in order to determine an adequate grid size required to resolve terrain forcing on mesoscale model simulation. One-dimensional spectral analysis is applied to specifically the central-eastern part of the Korean mountain region, where topographical-scale forcing has an important effect on mesoscale atmospheric flow. It is found that the terrain height variance spectra in this mountain region has a wavelength dependence with the power law exponents of 1.5 at the wavelength near 30 km, but this dependence is steeply changed to 2.5 at the wavelength less than 30 km. For the adequate horizontal grid size selection on mesoscale simulation two-dimensional terrain height spectral analysis is also performed. There is no directionality within 50% of spectral energy region, so one-dimensional spectral analysis can be reasonably applied to the Korea Peninsula. According to the spectral analysis of terrain height variance, the finer grid size which is higher than 6 km is required to resolve a 90% of terrain variance in this region. Numerical simulation using WRF (Weather Research and Forecasting Model) was performed to evaluate the effect of different terrain resolution in accordance with the result of spectral analysis. The simulated results were quantitatively compared to observations and there was a significant improvement in the wind prediction across the mountain region as the grid space decreased from 18 km to 2 km. The results will provide useful guidance of grid size selection on mesoscale topographical simulation over the Korean mountain region.

• Atmosphere
• /
• v.17 no.4
• /
• pp.349-364
• /
• 2007

The main purpose of this study is to examine the sensitivity of the WRF (Weather Research and Forecasting) in the wind field to the steepness of mountains in the case with a strong downslope wind occurred in the Yeongdong province. We conducted WRF simulations for February 13 2006. The initial and boundary data are from the NCEP/NCAR $1^{\circ}{\times}1^{\circ}$ GDAS. Arbitrary terrains of the mountains with a symmetric orography and an asymmetric one with steeper leeward slope, were introduced to examine the sensitivity of the shape of the mountains. The simulation with an asymmetric terrain results in stronger maximum surface wind by about $10ms^{-1}$ than with a symmetric terrain, especially in the narrow region from the peak to ~ 4 km away in the downstream. However, the maximum surface wind speed is weaker by $20ms^{-1}$ than with a symmetric terrain away from the narrow peak region. This indicates that the steeper slope leads to the intensification of downslope wind in the narrower region leeward. In addition, for the simulation with an asymmetric terrain, the strength of wave breaking is greater and the Lee wave is more dominant than for that with a symmetric terrain.

• Wind and Structures
• /
• v.31 no.4
• /
• pp.363-371
• /
• 2020

Proper understanding of offshore wind speed variability is of essential importance in practice, which provides useful information to a wide range of coastal and marine activities. In this paper, long-term wind speed data recorded at various offshore stations are analyzed in the framework of fractal dimension analysis. Fractal analysis is a well-established data analysis tool, which is particularly suitable to determine the complexity in time series from a quantitative point of view. The fractal dimension is estimated using the conventional box-counting method. The results suggest that the wind speed data are generally fractals, which are likely to exhibit a persistent nature. The mean fractal dimension varies from 1.31 at an offshore weather station to 1.43 at an urban station, which is mainly associated with surface roughness condition. Monthly variability of fractal dimension at offshore stations is well-defined, which often possess larger values during hotter months and lower values during winter. This is partly attributed to the effect of thermal instability. In addition, with an increase in measurement interval, the mean and minimum fractal dimension decrease, whereas the maximum and coefficient of variation increase in parallel.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 1997.11a
• /
• pp.305-310
• /
• 1997

There are many parameters in prediction of forest fire spread. The variables such as fuel moisture, fuel loading, wind velocity, wind direction, relative humidity, slope, and solar aspect have important effects on fire. Particularly, wind and slope factors are considered to be the most important parameters in propagation of forest fire. Generally, slope effect cause different wind distribution in mountain area. However, this effect is disregarded in complex geometry. In this paper, wind is estimated by applying computational fluid dynamics to the forest geometry. Wind velocity data is obtained by using CFD code with Newtonian model and slope is calculated with geometrical data. These data are applied fer 2-dimentional forest fire spreading algorithm with Korean ROS(Rate Of Spread). Finally, the comparison between the simulation and the real forest fire is made. The algorithm spread of forest fire will help fire fighter to get the basic data far fire suppression and the prediction to behavior of forest fire.

• Journal of the Korean Solar Energy Society
• /
• v.35 no.2
• /
• pp.1-10
• /
• 2015

Promising onshore wind farm sites in Gangwon province of Korea were investigated in this study. Gangwon province was divided into twenty five simulation regions and a commercial program based on Reynolds averaged Navier-Stokes equation was used to find out wind resource maps of the regions. The national wind atlas with a period 2007-2009 developed by Korea institute of energy research was used as climatologies. The wind resource maps were combined to construct a wind resource map of Gangwon province with a horizontal spatial resolution of 100m. In addition to the wind resource, national environmental zoning map, distance from substation, residence and automobile road, Beakdudaegan mountain range, terrain slope, airport and military reservation district were considered to find out promising wind farm sites. A commercial wind farm design program was used to find out developable wind farm capacities in promising wind farm site with and without excluding environmental protection regions. The total wind farm capacities with and without excluding the protection regions were estimated to be 46MW and 598MW, respectively, when a 2MW commercial wind turbine was employed.

• Structural Engineering and Mechanics
• /
• v.63 no.4
• /
• pp.509-519
• /
• 2017

Wind field in mountainous regions demonstrates unique distribution characteristic as compared with the wind field of the flat area, wind load and wind effect are the key considerations in structural design of television towers situated in mountainous regions. The television tower to be constructed is located at the top of Xiushan Mountain in Nanjing, China. In order to investigate the impact of terrain factors of hilltops on wind loads, firstly a wind tunnel test was performed for the mountainous area within 800m from the television tower. Then the tower basal forces such as bending moments and shear strength were obtained based on high frequency force balance (HFFB) test. Based on the experiments, the improved method for determining the load combinations was applied to extract the response distribution patterns of foundation internal force and peak acceleration of the tower top, then the equivalent static wind loads were computed under different wind angles, load conditions and equivalent goals. The impact of terrain factors, damping ratio and equivalent goals on the wind load distribution of a television tower was discussed. Finally the equivalent static wind loads of the television tower under the 5 most adverse wind angles and 5 most adverse load conditions were computed. The experimental method, computations and research findings provide important references for the anti-wind design of high-rise structure built on hilltops.

• Journal of Korean Society of Forest Science
• /
• v.95 no.3
• /
• pp.282-290
• /
• 2006

Forest vegetation types were studied by the phytosociological investigation and the TWINSPAN method in Ulleung Island, Korea. Two hundred thirty-two releves were sampled with $100m^2$ plots. Two main vegetation types, the mountain forest(Acer okamotoanum community group) and maritime forest(Artemisia scoparia community group), have been distinguished and typified twenty-two vegetation units. The former was divided in 4 communities, 11 groups and 7 subgroups. The latter was 2 communities and 5 groups. In a case of life-forms of mountain and maritime vegetation type, the composition ratio of species that had featured trees and herbs, hemicrypthophyte, a seed dispersion-type by wind or nature falling and erection form was high in the mountain vegetation type. Species that had featured shrubs, chamaephyte, disseminated mainly by a wind in the herbs, and animals and man or no special modification in the woody, narrowest extent of rhizomatous growth and the clonal growth by stolons and struck roots and procumbent form were abundantly distributed in the maritime bluff vegetation type. Particularly, the composition ratio of Sambucus sieboldiana var. pendula community(A6), disturbed vegetation type of middle-lower slope of mountain, that had featured a seed dispersion-type by wind, moderate and narrowest extent of rhizomatous growth and Tussock form was high.

• Journal of the Korean earth science society
• /
• v.25 no.8
• /
• pp.784-798
• /
• 2004

Microscale wind fields were simulated by MUKLIMO at the Naro Space Center, where complicated mountainous terrain and trees exist. In order to test the model's sensitivity with the effects of terrain and trees, experimental simulations were conducted under the various initial conditions. The experiments showed that the effects of trees were more significant on flat surfaces than on mountain cliffs. Based on the results, an actual 10 m level microscale wind field was simulated at the Naro Space Center, which has complicated mountainous terrain. Simulations of wind fields before and after the construction of the launching site were also conducted. It was found that MUKLIMO was of the mesoscale wind fields at the Naro Space Center.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.17 no.2 s.119
• /
• pp.114-120
• /
• 2007

Vibration performance of a 6 kW stand-alone wind turbine(W/T) generator is investigated under the wind environment of Daegwanryung mountain area. In the W/T, wind condition, power performance and structural stability are correlated each other An integrated monitoring system which consists of accelerometers, anemometers, power meters and auxiliary sensors for atmospheric data are constructed to measure the required data simultaneously. Based upon the data acquired over a long period of time, vibration performance of the W/T structure is estimated with annual wind data and generating power performance. Within the operating speed range, possibility of severe nitration is diagnosed. Vibration sources are identified and countermeasures are proposed. The goal of the study is to offer the basic information on W/T vibration performance at the design stage of a small stand alone W/T structure.