• Journal of Korean Society for Atmospheric Environment
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• v.15 no.3
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• pp.223-233
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• 1999

The wind-flow characteristics over a two-dimensional triangular prism with a porous windbreak are numerically investigated. The geometry is a simplified model of large outdoor stack with a frontal wall-type windbreak which is used to prevent particle dispersion by reducing wind speed over stak surface. In the present numerical model, the RNG k-$\varepsilon$ model, the orthogonal grid system and the QUICK scheme are employed for the successful simulation of separated flow. The predicted results are compared and validated with the associated wind-tunnel experiments. In addition, the trajectories of dispersed particles and their sedimentation characteristics are quantitatively investingated using a Lagrangian turbulent-dispersion model.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.145-154
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• 2013

Recently, damage occurrence by wind erosion has been increasing in society. In times past, such problems only took place in desert area ; however, in recent years, the wind erosion problem is spreading out to agricultural land. Wind erosion in agricultural land can cause loss of loam soils, the disturbance of the photosynthesis of the crop fields and serious economic losses. To overcome the mentioned problems, installation of windbreak fence can be recommended which function as disturbing strong wind and wind erosion. However, there is still no proper guideline to install the windbreak fence and the installation used to rely on the intuition of the workers due to the lack of related studies. Therefore, this study measured the aerodynamic resistance of screens of the windbreak fence using the apparatus for testing screens. The apparatus for testing screens was designed to measure pressure loss around the screen. Measured pressure loss by wall friction compensated for pressure loss to calculate the aerodynamic resistance of screens. The result of pressure loss by regression analysis derived the aerodynamic coefficient of Darcy-Forchheimer equation and power law equation. The aerodynamic resistance was constant regardless of the overlapped shape when the screen was overlapped into several layers. Increasing the number of layers of the screen, internal resistance increased significantly more, and pressure loss caused by the screen also increased linearly when the wind speed was certain conditions, but permeability had no tendency. In the future, the results of this study will be applied to the computational fluid dynamics simulation. The simulation models will be also validated in advance by wind tunnel experiments. It will provide standard of a design for constructing windbreak fence.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.4
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• pp.59-67
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• 2020

In this study, the effects of windbreak fences composed of natural vegetation on one-year-old seedlings were analyzed to develop restoration methods for an endangered subalpine species, the dwarf Siberian pine (Pinus pumila (Pall.) Regel). One-year-old seedlings were planted in 2016 by sowing seeds that had been collected from the Daecheongbong area on Mt. Seoraksan, South Korea, in 2014. The area near Daecheongbong was selected as the experimental site, and treatment and control plots (2m×2m) were installed at the site. To analyze the effects of wind protection, windbreak fences were constructed in the treatment plots using hairy Korean rhododendrons (Rhododendron mucronulatum Turcz. var. ciliatum Nakai) from the surrounding area and weather stations were installed to investigate atmospheric temperature, humidity, and wind speed. In all control plots without windbreak fences, dwarf Siberian pine seedlings were killed by strong winds seven months after planting. In contrast, the average survival rate of the seedlings in treatment plots was 96.7% after seven months, 64.2% after two years, and 45% after three years, with most (85.3%) of the seedlings showing good initial root establishment. Accordingly, windbreak fences composed of natural vegetation are suitable for promoting the early establishment of seedlings in the restoration of dwarf Siberian pine stands.

• Journal of Environmental Science International
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• v.19 no.11
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• pp.1423-1436
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• 2010

The effects of meteorological and reclaiming conditions on the reduction of suspended particles are investigated using a computational fluid dynamics (CFD) model with the k-$\varepsilon$ turbulence closure scheme based on the renormalization group (RNG) theory. Twelve numerical experiments with different meteorological and reclaiming conditions are performed. For identifying the meteorological characteristics of the target area and providing the inflow conditions of the CFD model, the observed data from the automatic weather station (AWS) near the target area is analyzed. Complicated flow patterns such as flow distortion, horse-shoe vortex, recirculation zone, and channeling flow appeared due to the topography and buildings in the domain. Specially, the flow characteristics around the reclamation area are affected by the reclaiming height, reclaiming size and windbreak height. Reclaiming height affected the wind speed above the reclaiming area. Windbreak induces more complicated flow patterns around the reclaiming area as well as within the reclaiming area. In front of the windbreak, flow is distorted as it impinges on the windbreak. As a result, upward flow is generated there. Behind the windbreak, a secondary circulation, so called, a recirculation zone is generated and flow is reattached at the end of the recirculation zone (reattachment point). At the lower part of the recirculation zone, there is a reverse flow toward the windbreak. Flow passing to the reattachment point starts to be recovered. Total amounts of suspended particles are calculated using the frictional and threshold frictional velocities, erosion potential function, and the number of surface disturbance. In the case of a 10 m-reclaiming and northerly wind, the amount of suspended particles is largest. In the presence of 5 m windbreak, the friction velocity above the reclaiming area is largely reduced. As a result, the total amount of the suspended particles largely decreases, compared to the case with the same reclaiming and meteorological conditions except for the windbreak The calculated suspended particle amounts are used as the emission rate of the dispersion model simulations and the dispersion characteristics of the suspended particles are analyzed.

• Korean Journal of Environment and Ecology
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• v.24 no.1
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• pp.69-77
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• 2010

The Jeongdori windbreak forests of Wando island, located between the sea and the land, are very important as ecological succession areas that protect cultivated lands and fishing villages. Among the Jeongdori windbreak forests, the rocky seashore areas are occupied by Sageretia theezans mantle community, and their inner sections by sub-tree layers such as Ligustrum japonicum and Ligustrum obtusifolium. More specifically, the inner sections of the rocky seashore areas were found to be the habitat of Ligustrum japonicum-Quercus variabilis community, Ligustrum jarponicum-Viburnum erosum community, Ligustrum japonicum-Cinnamomum japonicum community, Cinnamomum japonicum-Carpinus tschonoskii community, and Pinus densiflora-Viburnum erosum community. The average height of tree layers of the Jeongdori windbreak forests is 10.3m, and the average diameter at breath height are 30.3cm. Though the windbreak forests was artificially made, it is now virtually natural forest and deserves protection for ecological reasons. Designated as a scenic spot 3, it is always in the danger of being damaged by frequent tourist visits. So the Jeongdori windbreak forest needs to be continuous maintenance and management by the National Park Service. Considering of the precious cultural treasures of the famous pebble stones covering Gugyedeung and the naturality of the Jeongdori windbreak forests, the Jeongdori windbreak forests as a scenic spot have to designated as the national monument in future and will preserve by the Cultural Properties Administration.

• Journal of agriculture & life science
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• v.46 no.1
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• pp.71-81
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• 2012

This study was conducted to get basic information about making windbreak forest around Saemanguem reclaimed lands by analyzing the vegetation structure of 8 windbreak forests along the west coast of Korea and considering the methods of structural improvement. The total plants existing in the study areas were 25 families 40genus 43 species, and every tree layer consisted of only one tree species, Pinus thunbergii. There were 2 windbreak stands consisted of a species, and 2 consisted of multiple layer with a species. While, 4 windbreak stands consist of various species with several species. To make ecological system and functions of windbreak forests stabler, TL, STL and SL should be together in the vertical point, moreover, TL should be appeared at the in side and SL should be planted at the out side in the horizontal point. It is considered that mixed stand forest might be suitable for increasing the windbreak forest's functions and decreasing damage caused by disease and insects.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2005.04a
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• pp.126-133
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• 2005

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.4
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• pp.298-303
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• 2013

In this study, the installation effects of a windbreak net on reducing wind speed were examined using meteorological observation data. Three automatic weather systems (AWS) were installed at the inside of the windbreak net of an apple orchard along the distance, and one AWS was located at the outside. They were set up on Oct. $25^{th}$, 2012 at the apple orchard of Geochang County, and meteorological data, which were observed at four stations for about 1 year from October 26, 2012 through October 21, 2013, were used for this study. Meteorological variables include air temperature & relative humidity at a height of 1.5 meter, and wind speed & wind direction at a height of 2 meter and 4 meter. These variables were measured and recorded every 60 seconds. The preliminary results of this study was as follows: (1) Daily mean temperature at the inside of the windbreak net was lower than that of the outside by 0.1 through $0.2^{\circ}C$. (2) Daily mean relative humidity at the inside of the windbreak net was higher than that of the outside by 0.7 through 1.7%. (3) As compared to the outside, northerly daily maximum wind speed of the inside of the windbreak net at a height of 2 and 4 meter was reduced by 0.7~1.5 $ms^{-1}$ (30.4~65.2%) and 0.3~0.7 $ms^{-1}$ (10.3~24.1%), respectively.

• Korean Journal of Environment and Ecology
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• v.32 no.2
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• pp.147-153
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• 2018

There are few available studies for insect diversity in relation to coastal dune despite the unique landscape features and high conservation value. Therefore, this study compared ground beetle assemblages inhabiting between windbreak forests and sand dunes in the Taeanhaean National Park. It investigated five windbreak forests and three coastal dunes using pitfall traps from middle of June to middle of October in 2014. A total of 2,335 ground beetles belonging to 30 species of 15 genera were collected. Synuchus arcuarticollis (158 individuals) and Dolichus halensis halensis (153 individuals) were dominant of 25 specifies collected from sand dunes while Synuchus arcuarticollis (1,630 individuals), Synuchus nitidus (130 individuals), and Synuchus cycloderus (42 individuals) were dominant of 14 species collected from windbreak forests. The similarity of ground beetles compositions in sand dunes and windbreak forests was significantly low at 27.4%. The results of this study showed that sand dune geographical features found in the Taeanhaean National Park had different insect assemblages from windbreak forests. It will be the useful information for conservation of insects in the future.

• Journal of Korean Society of Forest Science
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• v.95 no.6
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• pp.751-758
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• 2006

To investigate soil management practices for increasing tree growth in arid regions of China, Xinjiang poplar (Populus alba var. pyramidalis) seedlings were planted in a nursery and windbreak and were treated with fertilizers (nitrogen and phosphorus) and absorbents (artificial; K-SAM and natural: Yuho (Artemisia ordosica)) at Dengkou in Inner Mongolia. Seedling height, diameter at breast height (DBH), biomass, and nitrogen (N) and phosphorus (P) concentrations were measured 1.5 years after the treatments. Soil texture was sandy loam for nursery and clay loam for windbreak, soil pH was 8.78 for nursery and 8.51 for windbreak, and total soil N concentration was 0.06% for nursey and 0.08% for windbreak. [n general, seedling height and DBH increased in the N fertilizer treatment compared to control or other treatments both in nursery and windbreak. Also seedling growth increased after the treatments of artificial and natural absorbents in windbreak. Total above- and belowground biomass increased after the N + P treatment. Foliage N and P concentrations following N and/or P treatments were same in the nursey, however, they significantly increased in the windbreak indicating N deficiency. It appeared that N was a limiting factor for early growth of Xinjiang poplar seedlings and artificial and natural absorbents (K-SAM and Yuho) would be useful to increase seedling growth in the arid region.