• Title/Summary/Keyword: Peak flow distribution

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Experimental study of rainfall spatial variability effect on peak flow variability using a data generation method (자료생성방법을 사용한 강우의 공간분포가 첨두유량의 변동성에 미치는 영향에 대한 실험적 연구)

  • Kim, Nam Won;Shin, Mun Ju
    • Journal of Korea Water Resources Association
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    • v.50 no.6
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    • pp.359-371
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    • 2017
  • This study generated flood time series of ungauged catchments in the Andongdam catchment using a distributed rainfall-runoff model and data generation method, and extracted the peak flows of 50 catchments to investigate the effect of rainfall spatial variability on peak flow simulation. The model performance statistics for three gauged catchments were reasonable for all events. The flood time series of the 50 catchments were generated using distributed and mean rainfall time series as input. The distribution of the peak flow using the mean rainfall was similar or slightly different to that using the distributed rainfall when the distribution of the distributed rainfall was nearly uniform. However, the distribution of the peak flow using the mean rainfall was reduced significantly compared to that using the distributed rainfall when actual storms moved to the top or bottom of the study catchment, or the rainfall was randomly distributed. These cases were 35% of total number events. Therefore, the spatial variability of rainfall should be considered for flood simulation. In addition, the power law relationship estimated using the peak flow of gauged catchments cannot be used for estimating the peak flow of ungauged independent catchments due to latter's significant variation of the peak flow magnitude.

Peak Discharge Change by Dirrerent Design Rainfall on Small Watershed

  • Jun, Byong-Ho;Jang, Suk-Hwan
    • Korean Journal of Hydrosciences
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    • v.3
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    • pp.97-104
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    • 1992
  • To design the minor structures in the small watersheds, it is required to calculate the peak discharge. For these calculations the simple peak flow prediction equations, the unit hydrograph method. the syntheic unit hydrograph methods or the runoff simulation models are adopted. To use these methods it is generally requried to know the amount and the distributions of the design rainfall; which are the uniform distribution, the trangular distribution, the trapezoidal distribution, or the Huff type distribution. In this study, the peak discharges are calculated by the different rainfall distributions and the results are compared.

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The Analysis of 2004 Summer Peak Load in Korea Power system (2004년 하계 첨두부하 시 계통운영 실적 분석)

  • Song, Tae-Yong;Hwang, Bong-Hwan
    • Proceedings of the KIEE Conference
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    • 2004.11b
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    • pp.113-115
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    • 2004
  • This year korea power system had recorded highest peak load for 6 times and finally it made new peak load 51,264MW at July 29th 3:00 PM. The new peak load is increased 8.2% from the last year peak load 47,385MW and korea power system entered 50,000MW load era. The Korea Power Exchange (KPX) snapped power system data at the peak load time using state estimation function in the EMS. And authors converted the power system data at peak load to PSS/E power flow format. Using this PSS/E peak load power flow data, this paper explains demand analysis result shun capacitor operation, voltage distribution at the peak load. And the paper shows the simulation result of 2 contingency analysis using the snapped PSS/E peak load data.

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Peak Discharge Change by Different Design Rainfall on Small Watershed (소규모유역에서 설계강우의 분포형태에 따른 첨두유량의 변화연구)

  • 김병호;장석환
    • Water for future
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    • v.24 no.1
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    • pp.93-97
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    • 1991
  • To design the minor structures in the small watersheds, it is required to calculate the peak discharge. For these calculations the simple peak flow prediction equations, the unit hydrograph method, the synthetic unit hydrograph methods or the runoff simulation models are adopted. To use these methods it is generally required to know the amount and the distributions, which are the uniform distribution, the triangular distribution, the trapezoidal distribution, or the Huff type distribution, of the design rainfall. In this study, the peak discharges are calculated by the different rainfall distribution and the values are compared.

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Construction of Speed Predictive Models on Freeway Ramp Junctions with 70mph Speed Limit (70mph 제한속도를 갖는 고속도로 연결로 접속부상에서의 속도추정모형에 관한 연구)

  • 김승길;김태곤
    • Journal of Korean Port Research
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    • v.14 no.1
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    • pp.66-75
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    • 2000
  • From the traffic analysis, and model constructions and verifications for speed prediction on the freeway ramp junctions with 70mph speed limit, the following results were obtained : ⅰ) The traffic flow distribution showed a big difference depending on the time periods. Especially, more traffic flows were concentrated on the freeway junctions in the morning peak period when compared with the afternoon peak period. ⅱ) The occupancy distribution was also shown to be varied by a big difference depending on the time periods. Especially, the occupancy in the morning peak period showed over 100% increase when compared with the 24hours average occupancy, and the occupancy in the afternoon peak period over 25% increase when compared with the same occupancy. ⅲ) The speed distribution was not shown to have a big difference depending on the time periods. Especially, the speed in the morning peak period showed 10mph decrease when compared with the 24hours'average speed, but the speed did not show a big difference in the afternoon peak period. ⅳ) The analyses of variance showed a high explanatory power between the speed predictive models(SPM) constructed and the variables used, especially the upstream speed. ⅴ) The analysis of correlation for verifying the speed predictive models(SPM) constructed on the ramp junctions were shown to have a high correlation between observed data and predicted data. Especially, the correlation coefficients showed over 0.95 excluding the unstable condition on the diverge section. ⅵ) Speed predictive models constructed were shown to have the better results than the HCM models, even if the speed limits on the freeway were different between the HCM models and speed predictive models constructed.

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Construction of Speed Predictive Models on Freeway Ramp Junctions with 70mph Speed Limit. (70mph 제한속도를 갖는 고속도로 연결로 접속부상에서의 속도추정모형에 관한 연구)

  • 김승길;김태곤
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 1999.10a
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    • pp.111-121
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    • 1999
  • From the traffic analyses, and model constructions and verifications for speed prediction on the freeway ramp junctions with 70mph speed limit, the following results obtained: ⅰ) The traffic flow distribution showed a big difference depending on the time periods. Especially, more traffic flows were concentrated on the freeway junctions in the morning peak period when compared with the afternoon peak period. ⅱ) The occupancy distribution was also shown to be varied by a big difference depending on the time periods. Especially, the occupancy in the morning peak period showed over 100% increase when compared with the 24hours average occupancy, and the occupancy in the afternoon peak period over 25% increase when compared with the same occupancy.ⅲ) The speed distribution was not shown to have a big difference depending on the time periods. Especially, the speed in the morning peak period shown 10mph decrease when compared with the 24hours' average speed, but the speed did not show a big difference in the afternoon peak period.ⅳ) The analyses of variance showed a high explanatory power between the speed predictive models(SPM) constructed and the variables used, especially the upstream speed. ⅴ) The analysis of correlation for verifying the speed predictive models(SPM) constructed on the ramp junctions were shown to have a high correlation between observed data and predicted data. Especially, the correlation coefficients showed over 0.95 excluding the unstable condition on the diverge sectionⅵ) Speed predictive models constructed were shown to have the better results than the HCM models, even if the speed limits on the freeway were different between the HCM models and speed predictive models constructed.

Comparison and analysis of peak flow by Areal Reduction Factor (면적감소계수에 따른 첨두유량의 비교연구)

  • Baek, Hyo-Sun;Lee, De-Young;Kang, Young-Buk;Choi, Han-Kuy
    • Proceedings of the Korea Water Resources Association Conference
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    • 2007.05a
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    • pp.1798-1802
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    • 2007
  • The practice of business estimate flood discharge by rainfall-flow relation that is easy collection of observation data. The important factor is rainfall, coefficient of runoff, and drainage area for analysis of runoff-flow relation.The practice of business usually use probability rainfall that use a weighted average value after each observation post estimate probability of non-same time. It has more error than same time probability rainfall, and it can excess of estimation because it can't consider space distribution of rainfall.The study of result showed similar aspect with existing ARF but width of coefficient become smaller. And the comparison of peak flow did not different what used by ARF and same time probability rainfall(A group). But non-same time probability rainfall is bigger 25% more than another(B group). Between A group and B group of the difference increased with the lapse of time.

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Comparison and analysis of peak flow by Areal Reduction Factor (면적감소계수에 따른 첨두유량의 비교 분석)

  • Lee, Dae-Young;Choi, Han-Kuy
    • Journal of Industrial Technology
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    • v.27 no.A
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    • pp.95-102
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    • 2007
  • The practice of business estimate flood discharge by rainfall-flow relation that is easy collection of observation data. The important factor is rainfall, coefficient of runoff, and drainage area for analysis of runoff-flow relation. The practice of business usually use probability rainfall that use a weighted average value after each observation post estimate probability of non-same time. It has more error than same time probability rainfall, and it can excess of estimation because it can't consider space distribution of rainfall. The study of result showed similar aspect with existing ARF but width of coefficient become smaller. And the comparison of peak flow did not different what used by ARF and same time probability rainfall(A group). But non-same time probability rainfall is bigger 25% more than another(B group). Between A group and B group of the difference increased with the lapse of time.

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Synthesis and Analysis of Nanosized TiO2 Particles Using a Tube Furnace (튜브 전기로를 이용한 TiO2 나노입자의 합성 및 특성 분석)

  • 배귀남;현정은;이태규;정종수
    • Journal of Korean Society for Atmospheric Environment
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    • v.20 no.3
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    • pp.411-419
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    • 2004
  • Titania particles are widely used as a photocatalyst to treat various contaminants in air and water. Titania particles were formed by vapor-phase oxidation of titanium tetraisopropoxide (TTIP) in a tube furnace between 773 and 1,273 K. The effect of process variables such as furnace temperature, flow rate of carrier air, and flow rate of sheath air on powder size and phase characteristics was investigated using a scanning mobility particle sizer (SMPS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The size distribution of synthesized titania particles was characterized with mode diameter and peak concentration. The mode diameter ranging from 20 to 80 nm decreased with increasing flow rates of sheath air and carrier air, and increased with increasing furnace temperature. The peak concentration increased with increasing flow rates of sheath air and carrier air The best synthetic condition for high production rate can be derived from the experimental data set represented by mode diameter and peak concentration. The crystal structure of synthesized titania particles was found to be anatase phase, ensuring high photocatalytic potential.

A Study on the Laminar Flow Field and Heat Transfer Coefficient Distribution for Supercritical Water in a Tube (초임계상태의 물에 대한 관 내 층류유동장 및 열전달계수 분포특성에 관한 연구)

  • 이상호
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.9
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    • pp.768-778
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    • 2003
  • Numerical analysis has been carried out to investigate laminar convective heat transfer in a tube for supercritical water near the thermodynamic critical point. Fluid flow and heat transfer are strongly coupled due to large variations of thermodynamic and transport properties such as density, specific heat, viscosity, and thermal conductivity near the critical point. Heat transfer characteristics in the developing region of the tube show transition behavior between liquid-like and gas-like phases with a peak in heat transfer coefficient distribution near the pseudocritical point. The peak of the heat transfer coefficient depends on pressure and wall heat flux rather than inlet temperature and Reynolds number, Results of the modeling provide convective heat transfer characteristics including velocity vectors, temperature, and the properties as well as the heat transfer coefficient. The effect of proximity to the critical point is considered and a heat transfer correlation is suggested for the peak of Nusselt number in the tube.