• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.185-187
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• 2009

This paper describes development of a hardware simulator for the PMSG wind power system. The simulator consists of a realistic wind turbine model using anemometer, vector drive, induction motor. The turbine model generates torque and speed signals for a specific wind turbine with real wind speed. The torque and speed signals are scaled down to fit for the input power of 3kW PMSG. The hardware simulator was developed through computer simulations, and the operation was confirmed by experimental works.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.2
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• pp.136-143
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• 1997

직경 비가 0.56인 이중동심관에 내외측모두 매끈한 벽면, 벽면 거칠기를 안측, 외측, 그리고 양측 모두의 4경우에 대한 난류 유동과 열전달특성을 실험과 이론으로 연구하였다. 시간평균속도분포, 마찰계수, 그리고 최대 속도 지점과 전단응력이 0인 지점들을 피토튜브와 X형 열선 풍속계로 측정하였다. 이중동심관내에서 4가지 경우에 따른 사각돌출형 거칠기효과가 난류 유동과 열전달에 미치는 영향을 수정난류모델을 기초로 하여 연구하였다. 직경비, 거칠기 위치, 레이놀즈수, 그리고 프란틀수 등의 여러 변수에 의해서 난류 유동과 열전달을 고찰하였다. 본 연구는 전체적 효율 측면에서 유리하게 열전달율을 향상시킬수 있는 거칠기 구조를 밝혔다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2067-2068
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• 2008

해안지방의 염분 누적오손 특성을 분석하기 위하여 등가염분부착밀도(ESDD : Equivalent Salt Deposit Density) 측정장치를 국내 112 곳을 선정하여 설치하였다. 해안에서 500m 지점에 풍향, 풍속계를 설치하고, 실시간으로 측정하여 바람에 의한 영향을 분석하였다. 2005년 10월부터 2007년 9월까지 측정한 결과 고창은 해안에서 50m 떨어진 지점에서 최대 D 등급, 2,000m 지점은 B등급까지 오손되었으며, 포항 호미곳은 D등급까지 오손되었다. 분석결과 동해안의 오손특성은 타 지역보다 해안에 가까울수록 부착밀도가 급격히 증가하였으나, 서해안보다는 오손정도가 낮고 남해안보다는 높게 나타났다.

• 한국전산유체공학회:학술대회논문집
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• 2002.05a
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• pp.164-170
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• 2002

Numerical analysis of the flowfield around a 50-meter class airship is performed to determine the optimal position for the airspeed probe installation. The turbulent flow around the hull with gondola is analyzed to examine the characteristics of the data measured by the probe attached to the gondola, and they turned out to show the nonlinear relation between the freestream and measured angles of attack and be influenced by the Reynolds number. New position of the hull nose was proposed and the effect of various factors on the flowfield around the nose was also examined. The analysis with a panel method showed that the effect of empennage was negligible, and the effect of gondola and boundary layer thickness had also little impact. It was shown that the freestream angle of attack would be the only independent variable for the probe position around the hull nose in constructing the calibration matrix.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.248-249
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• 2010

This paper describes development of hardware simulator for the PMSG(Permanent Magnet Synchronous Generator) wind power system, which was designed using real wind data. The simulator consists of a realistic wind turbine model using anemometer, vector drive, induction motor. The turbine simulator generates torque and speed signals for a specific wind turbine with respect to given wind speed. This torque and speed signals are scaled down to fit the input of 3kW PMSG. The PMSG-side converter operates to track the maximum power point and the grid-side inverter controls the active and reactive power supplied to the grid. The operational feasibility was first verified by computer simulations with PSCAD/EMTDC. The feasibility of real system implementation was confirmed through experimental works with a hardware set-up.

• Journal of Aerospace System Engineering
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• v.15 no.3
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• pp.99-104
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• 2021

The characteristics of wind sensors were experimentally analyzed and compared for purposes of application in multicopter type drones. For rotating wind sensors, the dynamics effect causes measurement errors, while manufacturing errors and signal processing errors were found to constitute significant errors in ultrasonic sensors. In the ultrasonic sensor, the errors decrease as the distance of the transducer increases. These characteristics were experimentally confirmed, and it was established that ultrasonic sensors capable of outputting voltage or data of 10 Hz or more are suitable for use in multicopters.

• Journal of Wind Energy
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• v.4 no.2
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• pp.34-39
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• 2013

The wind resource assessment for measured wind data over 1 year by using the meteorological mast should be a prerequisite for business feasibility of the wind farm development. Even though the direction of boom mounting the wind vane and anemometer is carefully engineered to escape the interference of wakes generated from the met-mast structures, the shadow effect is not completely avoided due to seasonal winds in the Korean Peninsula. The shadow effect should be properly calibrated because it is able to distort the wind resources. In this study a calibration method is introduced for the measured wind data at Julpo in Jeonbuk Province. Each sectoral terrain conditions along the selected wind direction nearby the met-mast is investigated, and the distorted wind data due to shadow effects can be calibrated effectively. The correction factor is adopted for quantitative calibration by carrying out the WindSim analysis.

• Fire Science and Engineering
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• v.28 no.6
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• pp.22-27
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• 2014

In this study a Fuel bed where surface fire spreads through is made to measure the data such as the flame height, radiation, spread rate and temperature distribution of Fuel bed. As experimental variables species of trees, wind velocities and slop are chosen. Fallen leaves of Quercus Variabilis (Q.V.) and Pinus Densiflora (P.D.) are used as fuel. Wind velocity is controlled by simply designed wind turnnel from 1 to 5 m/s. Slope of fuel bed is changed from $0^{\circ}$ to $30^{\circ}$. For the measurements of temperature distribution and spread rate total 35 of K-type 1.6 mm thermocouples are positioned as a lattice design. Radiant heat flow meters are used besides video camera and thermovision camera.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.4
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• pp.153-178
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• 2018

Most operational uses of wind speed data require measurements at, or estimates generated for, the reference height of 10 m above mean sea level (AMSL). On the Ieodo Ocean Research Station (IORS), wind speed is measured by instruments installed on the lighthouse tower of the roof deck at 42.3 m AMSL. This preliminary study indicates how these data can best be converted into synthetic 10 m wind speed data for operational uses via the Korea Hydrographic and Oceanographic Agency (KHOA) website. We tested three well-known conventional empirical neutral wind profile formulas (a power law (PL); a drag coefficient based logarithmic law (DCLL); and a roughness height based logarithmic law (RHLL)), and compared their results to those generated using a well-known, highly tested and validated logarithmic model (LMS) with a stability function (${\psi}_{\nu}$), to assess the potential use of each method for accurately synthesizing reference level wind speeds. From these experiments, we conclude that the reliable LMS technique and the RHLL technique are both useful for generating reference wind speed data from IORS observations, since these methods produced very similar results: comparisons between the RHLL and the LMS results showed relatively small bias values ($-0.001m\;s^{-1}$) and Root Mean Square Deviations (RMSD, $0.122m\;s^{-1}$). We also compared the synthetic wind speed data generated using each of the four neutral wind profile formulas under examination with Advanced SCATterometer (ASCAT) data. Comparisons revealed that the 'LMS without ${\psi}_{\nu}^{\prime}$ produced the best results, with only $0.191m\;s^{-1}$ of bias and $1.111m\;s^{-1}$ of RMSD. As well as comparing these four different approaches, we also explored potential refinements that could be applied within or through each approach. Firstly, we tested the effect of tidal variations in sea level height on wind speed calculations, through comparison of results generated with and without the adjustment of sea level heights for tidal effects. Tidal adjustment of the sea levels used in reference wind speed calculations resulted in remarkably small bias (<$0.0001m\;s^{-1}$) and RMSD (<$0.012m\;s^{-1}$) values when compared to calculations performed without adjustment, indicating that this tidal effect can be ignored for the purposes of IORS reference wind speed estimates. We also estimated surface roughness heights ($z_0$) based on RHLL and LMS calculations in order to explore the best parameterization of this factor, with results leading to our recommendation of a new $z_0$ parameterization derived from observed wind speed data. Lastly, we suggest the necessity of including a suitable, experimentally derived, surface drag coefficient and $z_0$ formulas within conventional wind profile formulas for situations characterized by strong wind (${\geq}33m\;s^{-1}$) conditions, since without this inclusion the wind adjustment approaches used in this study are only optimal for wind speeds ${\leq}25m\;s^{-1}$.

• Journal of the Korean Society for Railway
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• v.20 no.1
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• pp.11-19
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• 2017

Since operation of railway trains is a major source of particle pollution in tunnel air, a particle removal device can be an effective measure to remove wear particles. To obtain design conditions of the particle removal device that will be installed underneath the railway trains, the wind speed and particle concentration underneath the trains were investigated using a three-dimensional ultrasonic anemometer and a DustTrak aerosol monitor, respectively. The measurements were made for the trains running on Seoul Metropolitan Subway Line 5 on February 10, 2015. The data were analyzed according to the track geometry (straight, curved) and train speed pattern (acceleration, cruising, and deceleration) between stations. Train speed was also analyzed. The average wind speed and $PM_{10}$ concentration underneath the trains were ~30% of the train speed and ${\sim}200{\mu}g/m^3$ for both straight and curved sections. Average $PM_{10}$ concentration for deceleration sections was higher than that for acceleration sections.