• 조명전기설비학회논문지
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• 제28권5호
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• pp.82-91
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• 2014

The combined generator system by integrating several renewable energy sources can share the electrical infrastructure and therefore have the advantage of constructing not only the transmission system but also the power conversion system. Among the various combined renewable system, the wind power and wave power has a high possibility of future growth due to the economic feasibility in offshore environment. This kind of large-scale combined systems might be follow the determination by the transmission system operator's directions and control the output profile by focusing at PCC. However, both renewable energies are depend on the unpredictable environmental variation; it is needed to do the compensation devices. In this paper, the ESS compensation plan is proposed to do output determination of the combined generator system by paying attention to active power of utility grid with the analysis of the controllable elements of the wind and wave power generator. The improvement of the new application technique of the combined system is confirmed through using the PSCAD/EMTDC. The entire simulation process was designed by adopting the active power control according to the reference signal of TSO.

• 한국환경과학회지
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• 제30권11호
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• pp.925-936
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• 2021

The study was aimed to investigate the correlation between tidal effects and fog occurrence in Incheon and Mokpo, which are located in the middle and southern coasts of the West Sea of Korea, respectively. The investigation used meteorological data obtained from the automated synoptic observing systems and automatic weather stations and ocean data from tide stations from 2010 to 2019. Fog occurrence frequency was highest at high tide (Incheon, 41%; Mokpo, 45%). During fog event days at high tide, the dew-point depression was low (Incheon, 0.5℃; Mokpo, 0.4℃) and the relative humidity was high (Incheon, 97%; Mokpo, 98%). The wind speed was 2.4 m/s in Incheon and 2.0 m/s in Mokpo, and the main wind directions were west-southwesterly from Incheon and southwesterly from Mokpo. In the fog case study, tidal flats were covered with water before and after the fog started. During the fog period, both stations experienced negative air-sea temperature differences, low dew-point depression, and high relative humidity were maintained, with weak winds forming from the tidal flats to the shore.

• Wind and Structures
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• 제38권5호
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• pp.381-398
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• 2024

This study presents a mode analysis of 3D turbulent velocity data around a square-section building model to identify the dynamic system for Kármán-type vortex shedding. Proper orthogonal decomposition (POD) was first performed to extract the significant 3D modes. Magnitude-squared coherence was then applied to detect the phase consistency between the modes, which were roughly divided into three groups. Group 1 (modes 1-4) depicted the main vortex shedding on the wake of the building, with mode 2 being controlled by the inflow fluctuation. Group 2 exhibited complex wake vortexes and single-sided vortex phenomena, while Group 3 exhibited more complicated phenomena, including flow separation. Subsequently, a third-order polynomial regression model was used to fit the dynamics system of modes 1, 3, and 4, which revealed average trend of the state trajectory. The two limit cycles of the regression model depicted the two rotation directions of Kármán-type vortex. Furthermore, two characteristic periods were identified from the trajectory generated by the regression model, which indicates fast and slow motions of the wake vortex. This study provides valuable insights into 3D mode morphology and dynamics of Kármán-type vortex shedding that helps to improve design and efficiency of structures in turbulent flow.

• Wind and Structures
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• 제20권4호
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• pp.549-564
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• 2015

The three-dimensional unsteady incompressible Reynolds-averaged Navier-Stokes equations and k-${\varepsilon}$ double equations turbulent model were used to investigate the effect on the measurements of anemometers due to a passing high-speed train. Sliding mesh technology in Fluent was utilized to treat the moving boundary problem. The high-speed train considered in this paper was with bogies and inter-carriage gaps. Combined with the results of the wind tunnel test in a published paper, the accuracy of the present numerical method was validated to be used for further study. In addition, the difference of slipstream between three-car and eight-car grouping models was analyzed, and a series of numerical simulations were carried out to study the influences of the anemometer heights, the train speeds, the crosswind speeds and the directions of the induced slipstream on the measurements of the anemometers. The results show that the influence factors of the train-induced slipstream are the passing head car and tail car. Using the three-car grouping model to analyze the train-induced flow is reasonable. The maxima of horizontal slipstream velocity tend to reduce as the height of the anemometer increases. With the train speed increasing, the relationship between $V_{train}$ and $V_{induced\;slipstream}$ can be expressed with linear increment. In the absence of natural wind conditions, from the head car arriving to the tail car leaving, the induced wind direction changes about $330^{\circ}$, while under the crosswind condition the wind direction fluctuates around $-90^{\circ}$. With the crosswind speed increasing, the peaks of $V_X,{\mid}V_{XY}-V_{wind}{\mid}$ of the head car and that of $V_X$ of the tail car tend to enlarge. Thus, when anemometers are installed along high-speed railways, it is important to study the effect on the measurements of anemometers due to the train-induced slipstream.

• 생물환경조절학회지
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• 제32권1호
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• pp.57-63
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• 2023

본 연구에서는 새만금과 같은 간척지를 활용하여 대규모 첨단온실단지를 조성하는 경우 간척지의 환경적 특수성 중 높은 풍속에 따른 유리 단열재의 에너지 효율을 평가하였다. 현장에서 주로 사용되는 온실 단열재 중 4가지에 대한 평가 결과, 최대 37.4%의 에너지 차이를 보여, 온실 피복재의 선정이 중요함을 제시하였다. 이를 바탕으로 일반적인 내륙에서의 온실을 설계하는 것과 달리, 간척지에서는 내재해성 온실규격을 따라 시설을 설계하여야 하며, 에너지 소비량은 높아진 풍속과 재질을 고려하여 산정되어야 한다. 본 연구의 결과는 에너지 효율성을 온실 피복재의 종류와 풍속에 따라서 제시하고 있으며, 이는 대규모 첨단온실 조성 시 에너지 소비량을 예측하고, 이를 바탕으로 신재생에너지원을 포함하는 에너지 설계에 활용될 수 있다

• 토지주택연구
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• 제14권3호
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• pp.93-106
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• 2023

본 논문은 우리나라의 아파트를 대상으로 아파트 단지 유형에 따른 열환경 변화를 CFD 기법을 이용하여 시뮬레이션을 수행하고, 유형별 열환경을 평가하고자 하였다. 이를 위해 본 연구는 2000년대와 2010년대 주요 아파트 단지 유형에 대한 선행연구를 참고하여 4가지 유형을 추출한 후, 바람 유입 방향에 따른 아파트 단지 배치와 기온 변화를 분석하였다. 각 유형별로 타워형, 판상형, 혼합 주동 유형을 이용하여 표준화 모형을 제작하였으며, 이들 유형에 대해 총 8개 방향에서의 바람 유입 상황을 상정했다. 이러한 모형 및 조건을 바탕으로 CFD 시뮬레이션을 수행하였다. 그 결과, 타워형으로만 구성된 유형과 타워형을 단지 중앙에 배치하는 유형에서 바람의 방향과 상관없이 상대적으로 온도가 낮았은 것으로 나타났다. 이들 유형에서 단지 내부로 바람이 잘 유입되기 때문인 것으로 풀이되었다. 이러한 본 연구의 결과는 건물의 형태 및 단지의 배치 유형에 따라 바람의 유동 및 그에 따른 온도 분포 패턴이 상이한 것으로 나타나 설계 초기 단계에서 단지의 배치에 대한 신중한 고려가 필요함을 확인하다. 본 연구의 결과는 향후 아파트 단지의 초기 설계단계에서 지속 가능한 주거환경 조성을 위한 기초자료로 활용될 수 있을 것으로 기대된다.

• Ocean Science Journal
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• 제41권4호
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• pp.245-254
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• 2006

Long term wave climate of both extreme wave and operational wave height is essential for planning and designing coastal structures. Since the field wave data for the waters around Korean peninsula is not enough to provide reliable wave statistics, the wave climate information has been generated by means of long-term wave hindcasting using available meteorological data. Basic data base of hindcasted wave parameters such as significant wave height, peak period and direction has been established continuously for the period of 25 years starting from 1979 and for major 106 typhoons for the past 53 years since 1951 for each grid point of the North East Asia Regional Seas with grid size of 18 km. Wind field reanalyzed by European Center for Midrange Weather Forecasts (ECMWF) was used for the simulation of waves for the extra-tropical storms, while wind field calculated by typhoon wind model with typhoon parameters carefully analyzed using most of the available data was used for the simulation of typhoon waves. Design wave heights for the return period of 10, 20, 30, 50 and 100 years for 16 directions at each grid point have been estimated by means of extreme wave analysis using the wave simulation data. As in conventional methodsi of design criteria estimation, it is assumed that the climate is stationary and the statistics and extreme analysis using the long-term hindcasting data are used in the statistical prediction for the future. The method of extreme statistical analysis in handling the extreme vents like typhoon Maemi in 2003 was evaluated for more stable results of design wave height estimation for the return periods of 30-50 years for the cost effective construction of coastal structures.

• 한국환경보건학회지
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• 제35권4호
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• pp.304-314
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• 2009

A new harbor as been constructing in Gadukdo. However, a lot of fugitive dust gas been often generated from construction site reclaiming sea sand, especially when the Northwester is blown strongly. It has resulted insome appeals of residents in Gadukdo. In this study, we estimated the amount of fugitive dust caused by new harbor construction using Fugitive dust formula. Also, the concentration of PM10 for recipient is predicted by AERMOD. The amount of fugitive dust is 26.56 ${\mu}g/sec{\cdot}m^2$ and 11.84 ${\mu}g/sec{\cdot}m^2$ respectively by the Fugitive dust formula. PM10 outlet concentration and the amount of fugitive dust increase according to wind velocity and directions. AERMOD is performed on the basis of weather data and the amount of fugitive dust generated with wind velocity. As a result of AERMOD, the PM10 concentration of Sunchang and Oinul are predicted over 100 ${\mu}g/m^3$. The PM10 concentration of Sunchang and Oinul are predicted over 130 ${\mu}g/m^3$ when wind velocity of northwester in winter is over 11 m/s (Air Quality for Particulate Matter (100 ${\mu}g/m^3$ for 24 hours)). Also, the measured error between AERMOD and actual measurement is lower than 5%.

• 한국수산과학회지
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• 제25권6호
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• pp.457-473
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• 1992

양향성 대륙붕에서 1차 파동방정식은 양 해안경계에서의 바람응력과, 대륙붕폭에 걸친 바람응력의 회전효과를 갖는다. 황해에서 바람응력 회전효과는 대륙붕파를 발생시키는 힘으로서 무시될 수 있다. 켈빈파는 대륙붕파보다 약화될 때까지의 거리가 매우 크기 때문에 황해 북쪽만(별)을 거의 약화되지 않고 통과할 수 있다. 파동특성을 따라 적분하는 수치방법은 반대방향으로 전파되는 파동을 수용하기 위해 조절되었다. 보다 실제와 가까운 해안선을 사용한 결과, 모델재생이 해류에서는 개선되었으나 해수면에서는 거의 개선되지 않았다. 이것은 해수면을 주로 결정하는 켈빈파가 해저지형의 변화에 영향을 극히 적게 받음을 의미한다 보다 개선된 해수면 재생을 위해서는 동지나 해에서 황해로 전파되는 켈빈파의 에너지를 알 필요가 있다. 해안을 따른 순풍류와 골을 따른 역풍류의 기본구조는 계절풍에 의해 발생하는 황해의 계절순환을 뒷받침한다.

• 국제초고층학회논문집
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• 제2권3호
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• pp.257-269
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• 2013

This study presents the development of an advanced multiple database-enabled design module for high-rise buildings (DEDM-HR), which seamlessly pools databases of multiple high frequency base balance measurements from geographically dispersed locations and merges them together to expand the number of available building configurations for the preliminary design. This feature offers a new direction for the research and professional communities that can be utilized to efficiently pool multiple databases therefore expanding the capability of an individual database and improving the reliability of design estimates. This is demonstrated, in this study, by the unprecedented fusion of two major established databases, which facilitates interoperability. The DEDM-HR employs a cyberbased on-line framework designed with user-friendly/intuitive web interfaces for the convenient estimation of wind-induced responses in the alongwind, acrosswind and torsional directions with minimal user input. In addition, the DEDM-HR embeds a novel feature that allows the use of wind characteristics defined in a code/standard to be used in conjunction with the database. This supplements the provisions of a specific code/standard as in many cases guidance on the acrosswind and torsional response estimates is lacking. Through an example, results from several international codes and standards and the DEDM-HR with the embedded features are compared. This provision enhances the scope of the DEDM-HR in providing an alternative design tool with nested general provisions of various international codes and standards.