• 한국대기환경학회지
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• 제20권1호
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• pp.1-15
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• 2004

Sea/land circulation system is a representative mesoscale local circulation system in coastal area. In this study, wind fields around coastal area. Pohang, which is affected by this system was investigated and its detailed characteristic analysis was carried out. The following can be found out from the numerical simulation. Generally, at nighttime mountain winds prevail and land breeze toward the coastal area was well simulated During daytime, valley wind and sea breeze was simulated in detail. Especially, as a result of analyzing the land breeze path, it could be found along the coastline as it flows out through low land coastal area. In order to investigate the accuracy of model results. wind speed, temperature and wind direction of continuous typical sea/land breeze occurrence day was compared with observation data. Analyzing the characteristics of local circulation system was very hard because of horizontally sparse observation data but from the above result, a numerical simulation using RAMS, which satisfies the spatial high resolution, will provide more accurate results.

• 한국소음진동공학회논문집
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• 제18권6호
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• pp.612-618
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• 2008

Microphone array beamforming method has been recognized as an important aeroacoustic research field and become a standard technique in localizing sound sources. This method also used in flight acoustic measurement, and especially, it is very useful when measure sounds inside the wind tunnel. In measuring sound which is inside the wind tunnel by traditional beamforming method, there are some errors caused by airstream. The speed and the propagation path of the sound changes as it travel through the airstream. This makes the error which the position of sound is changed a little bit to the down stream direction. In this paper, validation test has made about the correction equation for this wind effects of previous researches. And beamforming including shear layer correction was performed about a sound source in the anechoic open-jet wind tunnel.

• 한국도로학회논문집
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• 제13권3호
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• pp.139-146
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• 2011

도로를 주행하는 차량이 강풍구간을 지날 때 바람에 의한 횡력으로 경로를 벗어나 추돌사고를 일으킬 수 있다. 또한 높은 풍속에서는 차량이 전도하면서 대형 사고를 유발할 수 있다. 본 연구에서는 우선 횡풍에 의한 차량의 경로이탈과 전도에 대한 해석 매카니즘을 고찰하였다. 그리고 차량의 횡풍 위험도를 파악하기 위해 승용차와 트럭 등 10종의 대표 차량에 대한 위험도 해석을 실시하였다. 또한 횡풍 위험도가 차량의 주행속도와 특성 등에 따라 많은 편차가 있으며, 편차 발생 원인을 분석하였다. 본 연구 결과는 강풍이 잦은 도로환경에서 주행안전성 확보 방안을 마련하기 위한 기초자료로 활용 가능할 것이다.

• 한국태양에너지학회 논문집
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• 제36권1호
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• pp.11-18
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• 2016

The local wind systems in the Pohang region were categorized into wind sectors. Still, thorough knowledge of wind resource assessment, wind environment analysis, and atmospheric environmental impact assessment was required since the region has outstanding wind resources, it is located on the path of typhoon, and it has large-scale atmospheric pollution sources. To overcome the resolution limitation of meteorological dataset and problems of categorization criteria of the preceding studies, the high-resolution wind resource map of the Korea Institute of Energy Research was used as time-series meteorological data; the 2-step method of determining the clustering coefficient through hierarchical clustering analysis and subsequently categorizing the wind sectors through non-hierarchical K-means clustering analysis was adopted. The similarity of normalized time-series wind vector was proposed as the Euclidean distance. The meteor-statistical characteristics of the mean vector wind distribution and meteorological variables of each wind sector were compared. The comparison confirmed significant differences among wind sectors according to the terrain elevation, mean wind speed, Weibull shape parameter, etc.

• 한국대기환경학회지
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• 제21권6호
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• pp.613-624
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• 2005

In this study, we investigated the characteristic of volatile organic compounds (VOCs) concentrations in Shiwha area, which were measured using the Open-path FTIR Gas Analyzer. The passive samplers were set for a certain period of time to obtain the average concentration of toluene, ethylbenzene, o-xylene and styrene. In addition, VOCs concentration contour maps were constructed using the Tecplot program to illustrate the VOCs concentration distribution. The residential area showed higher concentrations than the industrial area. And the summer had higher concentration value than the winter. Also, we confirmed that the VOCs concentrations ranged from 2 to several tens ppb in the vicinity of an industry than diffused VOC concentration, whereas those ranged from 0 to 5 ppb in most other areas. It was conferred that the wind change with seasons significantly affects the distribution of VOCs concentrations such as a northwesterly wind in the winter or a southwestern wind in the summer.

• 풍력에너지저널
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• 제14권3호
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• pp.100-108
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• 2023

The aim of this study is to develop guidelines for predicting interference between drones and wakes during non-destructive blade inspections in wind power systems. The wake generated by wind towers and blades can affect the stability of drone flights, necessitating the establishment of guidelines to ensure safe and efficient inspections. In order to predict the interference between drones and blades, environmental variables must be considered, including quantification of turbulence intensity in the wake generated by the tower and blades, as well as determining the appropriate distance between the drone and the tower/blades for flight stability. To achieve this, computational fluid dynamics (CFD) analysis was performed using cross-sectional geometries corresponding to the main wind turbine blade and tower span locations. Based on the CFD analysis results, a safe flight path for drones is proposed, which minimizes the risk of collision and interference with towers and blades during maintenance operations of wind power systems. Implementation of the proposed guidelines is expected to enhance the safety and efficiency of maintenance work.

• 신재생에너지
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• 제17권4호
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• pp.1-8
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• 2021

To determine the wind turbine class in the offshore of the Korean Peninsula, the reference wind speed for a 50-y return period at the hub height of a wind turbine was estimated using the reanalysis data sets. The most recent reanalysis data, ERA5, showed the highest correlation coefficient (R) of 0.82 with the wind speed measured by the Southwest offshore meteorological tower. However, most of the reanaysis data sets except CFSR underestimated the annual maximum wind speed. The gust factor of converting the 1 h-average into the 10 min-average wind speed was 1.03, which is the same as the WMO reference, using several meteorological towers and lidar measurements. Because the period, frequency, and path of typhoons invading the Korean Peninsula has been changing owing to the climate effect, significant differences occurred in the estimation of the extreme wind speed. Depending on the past data period and length, the extreme wind speed differed by more than 30% and the extreme wind speed decreased as the data period became longer. Finally, a reference wind speed map around the Korean Peninsula was drawn using the data of the last 10 years at the general hub-height of 100 m above the sea level.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.92-96
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• 2007

Microphone array beamforming method has been recognized as an important aeroacoustic research field and become a standard technique in localizing sound sources. This method also used in flight acoustic measurement, and especially, it is very useful when measure sounds inside the wind tunnel. In measuring sound which is inside the wind tunnel by traditional beamforming method, there are some errors caused by airstream. The speed and the propagation path of the sound changes as it travel through the airstream. This makes the error which the position of sound is changed a little bit to the down stream direction. In this paper, validation test has made about the correction equation for this wind effects of previous researches. And beamforming including shear layer correction was performed about a sound source in the anechoic open-jet windtunnel.

• 한국해양학회지:바다
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• 제9권3호
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• pp.130-136
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• 2004

In September 2003 wind-measuring drifters were air-deployed in front of the projected path of Hurricane Fabian from an altitude between 300 m and 400 m. Eight drifters transmitted wind, air pressure and SST data through ARGOS and three drifters were within 35 km of the hurricane center. Measurements of the air pressure in the eye of the hurricane by dropsondes, suggested the air pressure at the eye was between 939 hPa and 944 hPa. The lowest pressure measured by a Minimet was 943 hPa at 33 km from the hurricane center. Fabian cooled the SST at its center from $28.9^{\circ}C$ to $26.8^{\circ}C$. After the passage of Fabian, SST warmed to between $27.5^{\circ}C$ and $28.5^{\circ}C$ in 7 days.

• 한국군사과학기술학회지
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• 제19권2호
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• pp.252-260
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• 2016

Unlike terrestrial transportation, marine transportation should consider environment factors in order to optimize path planning. This is because, ship's path planning is greatly influenced by real-time ocean environment-sea currents, wave and wind. Therefore, in this study, we suggest a ship path planning algorithm based on real-time ocean environment using not only $A^*$ algorithm but also path smoothing method. Moreover, in order to improve objective function value, we also consider ship's moving distance based on ship's location and real-time ocean environment data on grid map. The efficiency of the suggested algorithm is proved by comparing with $A^*$ algorithm only. This algorithm can be used as a reasonable automatics control system algorithm for unmaned ship.