• Journal of Wetlands Research
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• v.12 no.3
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• pp.155-163
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• 2010

The flash flood is characterized as flood leading to damage by heavy rainfall occurred in steep slope and impervious area with short duration. Flash flood occurs when rainfall exceeds Flash Flood Guidance(FFG). So, the accurate estimation of FFG will be helpful in flash flood forecasting and warning system. Say, if we can reduce the uncertainty of rainfall-runoff relationship, FFG can be estimated more accurately. However, since the rainfall-runoff models have their own parameter characteristics, the uncertainty of FFG will depend upon the selection of rainfall-runoff model. This study used four rainfall-runoff models of HEC-HMS model, Storage Function model, SSARR model and TANK model for the estimation of models' uncertainties by using Monte Carlo simulation. Then, we derived the confidence limits of rainfall-runoff relationship by four models on 95%-confidence level.

• Journal of the Korean Society of Visualization
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• v.10 no.3
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• pp.30-36
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• 2012

We are planning to construct a scaled-down moderator facility to simulate the CANDU-6 moderator circulation phenomena during steady state operating and accident conditions. In the present work a preliminary experiment using a 1/40 scaled-down moderator tank has been performed to investigate the anticipated problems of the flow visualization and measurement in the planning scaled-down moderator facility. We shortly describe CFD analysis result for the 1/40 scaled-down test model and the flow measurement techniques used for this test facility under isothermal flow conditions. The Particle Image Velocimetry (PIV) method is used to visualize and measure the velocity field of water in a transparent Plexiglas tank. Planar Laser Induced Fluorescence (PLIF) technique is used to evaluate the feasibility of temperature field measurement in the range of $20-40^{\circ}C$ of water temperature using an one-color method.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.1
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• pp.40-49
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• 1993

The Objectives of this paper were to develop a modified tank model that is capable of simulating daily streamflow from a small watershed using daily watershed evapotranspiration and to test the applicability of the model to different watersheds. Tank model was restructured to consist of three series of tanks, each of which may mathematically reflect watershed runoff mechanisms from different components of surface runoff, interflow, and baseflow. And pan evaporation was correlated to potential evapotranspiration estimated from a combination method, and was multiplied by monthly crop and landuse coefficients, and watershed storage coefficient to estimate the watershed evapotranspiration losses. Ten watersheds were selected to calibrate model parameters that were defined using an optimization scheme, and the results were correlated with watershed parameters. Simulated daily runoff was compared to the observed ones from the tested watersheds. The simulating results were in good agreement with the observed values when optimal and calibrated parameters were used. Ungaged conditions were also applied to compare simulated values to the observed. And the results were in fair conditions for all the tested watersheds which differ considerably in their sizes, landuse types, and physiological features.

• Journal of Korean Society on Water Environment
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• v.23 no.3
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• pp.403-409
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• 2007

This study was carried out to recommend the systematic improving practice for the effective operation of septic tank, and the evaluation of its BOD and nutrient removal efficiency depending on process, the survey of characteristics of FRP material, and the suggestion of optimum septic tank model within sewage treatment area. The average BOD concentration and BOD removal efficiency of septic tank which was carried out the cleaning periodically in 63.9 mg/L and 77.8%, shows good quality better than the septic tank which was not carried out the cleaning regularly. Maximum load of tensile, flexural and compressive strength increased in proportion to its thickness, and the contents standard 25% of glass fiber required upgrade over than 30%. Configuration and performance for the optimum of the septic tank suggests that over $0.75m^3$ of the effective total volume, adding to over $0.25m^3$ a man for more than 5 men of the treated person, retention time should be within one day. Improving plans about facility and materials quality of the septic tank have an obligation that protective wall ought to install on the concrete bottom and side faces to prevent crumble or transform from loading of the ground or upper part of the structure on the tank setting. And it is eliminated the uneffective resisting pressure and it keeps off circulate imperfect products by strengthening of the test methods such as stretching strength, pressing strength, glass fiber contents and thickness.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.6
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• pp.390-398
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• 2013

In this paper, an experimental study on sloshing problems in an independent B-type tank of STX Offshore and Shipbuilding Co. is described. Recently STX Offshore and Shipbuilding Co. introduced a new design of an independent B-type tank in order to reduce sloshing impact loads on LNG CCS. This tank has many internal members, so that sloshing flow and the resultant hydrodynamic loads are very different from those in typical membrane tanks. In this study, a series of sloshing experiment have been carried out for 1/50 scale model, and the main characteristics of sloshing load on the independent tank are observed. The properly scaled internal members such as swash bulkhead, center bulkhead and stringers have been installed in the test tank model, but sloshing pressures are measured on the tank walls only. The forced excitation signals have been generated by using the predicted ship motion in irregular sea states. The characteristics of sloshing loads on this tank have been observed in different filling levels with various heading angles, and sea states. In this paper, some key findings from the model tests are discussed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.2
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• pp.42-52
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• 1986

This study involves the estimation of optimal ranges of parameters for a linear watershed model. A well-known TANK model was chosen and a linear combination of four tanks assumed. The model was used to simulate daily streamflow for six watersheds of different sizes and by a trial-and-error approach a set of optimal parameters defined. The parameters were related to watershed sizes and land use conditions. Optimal parameters for ungaged conditions were defined from the relationships; daily streamflow simulated and compared to the observed date. The simulated results were in a general agreement with the data.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.889-893
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• 2005

본 연구에서는 기후변화에 따른 신뢰성 높은 수자원 영향평가를 수행하기 위한 방안으로 유출모형에 따른 불확실성을 최소화할 수 있는 슈퍼앙상블 기법을 제안하였다. 유출모형들은 자연현상을 개념화하는 과정에서 목적에 따라 알고리즘이나 구조가 다르게 개발된다. 따라서 동일한 유역에 동일한 입력자료를 사용하더라도 유출모의 결과는 상이하며 이는 곧 불확실성으로 작용한다. 이러한 불확실성을 최소화하기 위한 방법으로 본 연구에서는 통계적기법인 인공신경망 모형을 이용하여 모형별 유출결과를 향상시킬 수 있는 슈퍼앙상블 기법을 개발하고 적용성을 분석하였다. 적용 대상유역으로는 한강수계에 위치한 괴산댐유역을 선정하였으며, 적용 모형으로는 일체형 모형인 Tank 모형과 준분포형 모형인 PRMS 모형을 이용하여 슈퍼앙상블을 구축하고 검정하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.169-173
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• 2009

돌발홍수는 급격한 경사와 많은 불투수층을 포함하고 있는 좁은 지역에서 짧은 지속기간의 강우강도를 가진 큰 강우가 내리는 경우 발생한다. 이러한 돌발홍수가 발생할 수 있는 강우의 양을 파악하기 위해서 돌발홍수기준(Flash Flood Guidance)을 산정하여 활용하고 있다. 돌발홍수기준은 수문모형으로부터 도출되는 강우-유출관계곡선에서 한계유출량에 대응되는 강우량을 의미한다.따라서 강우-유출관계가 갖고 있는 불확실성(uncertainty)을 최소화 할수록 돌발홍수기준을 정확하게 산정할 수 있으며, 수문모형은 각각 고유의 매개변수와 특성을 갖고 있으므로 어떠한 수문모형을 사용하여 강우-유출관계를 도출하느냐에 따라 불확실성의 정도가 크게 좌우된다. 본 연구에서는 네 개의 수문모형(HEC-HMS 모형, 저류함수모형, SSARR 모형, TANK 모형)의 모의값에 Monte Carlo 모의 방법을 적용하여 네 개의 수문모형에 대한 신뢰구간을 추정하여 제시하였다.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.290-297
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• 2004

In this paper, one of the harbour maneuvering tests is described. Its goal is to investigate the so-called crabbing performance of ships. By crabbing is meant the ability of the vessel to move sideways with the use of her own maneuvering devices like propellers, rudders, transverse thruster, etc. the 3m ferry model is made by ocean engineering wide tank in the university of ulsan. when the model ship is leaving and going to the quay, Transverse forces and Yawing moments are measured, in the condition of zero longitudinal force and the design draught, by load cell attached to the longitudinal center of gravity on the ship. the purpose of the experiment is to verify the reliability of ocean wide tank in university of ulsan about crabbing test compared with results of foreign research institute.

• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.575-583
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• 2005

In this study the flow curve estimation is discussed using TANK model which is one of hydrologic models. The main interest is the accuracy of TANK model parameter estimation with respect to the sampling frequency of input data. For doing this, input data with various sampling frequencies is used to estimate model parameters. As a result, in order to generate relatively accurate flow curve, it is recommendable to measure stream flow at least every 8 days.