• 한국정밀공학회지
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• 제19권5호
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• pp.168-175
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• 2002

The hydraulic acoustic attenuator fur an automotive active suspension system is so highly nonlinear and of high order that the analysis in time-domain has been performed quite little. In this paper, a state-space representation of the dynamics for a hydraulic attenuator was presented utilizing the electrical analogy. And the results of experiment were compared with those of simulation to validate the state-space model proposed. The comparison revealed that the state-space model proposed is practically applicable to estimate the dynamic responses of the hydraulic attenuator in time-domain.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.1931-1934
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• 2006

The accuracy impact of using high-order Boussinesq-type model as compared to the typical order model is examined in this paper. The multi-layer model developed by Lynett and Liu(2004a) is used for simulating of wave breaking over a step region. The overall comparisons between the two-layer model and the hydraulic experiments are quite good. The one-layer model overshoals the wave near the breakpoint, while the two-layer model shoals at a rate more consistent with the experimental data.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.167-174
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• 1997

In this paper, the mathematical model of the hydraulic control valve is formulated, that is, this dynamic modeling which includes the motion equations and continuity equations can analyze the dynamic characteristics of the hydraulic control valve. The control valve for the transmission has the Over Speed Protection to protect a hydraulic travel motor. Therefore, this simulation shows the over speed protection and researches the main design parameters. The results of the computer simulation were assured through the experiment. From the comparison between both results, it is shown that this simulation program is useful and effective.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.1313-1317
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• 2006

In this study, various hydraulic phenomena were analyzed from the dam model experiments and the analyzed results were compared with existing computation results. Sungduk dam model structures were constructed using Froude similarity law by 1:50 scale. From the measurements of hydraulic phenomena at spillway channel, an improvement method was trying to be suggested over shortcoming of existing design plan. The result of model experiment showed no big difference with that of each part's numerical interpretation. Sidewall overflows were observed, as water conveyance occurred due to the linear characteristics of spillways, which raised the necessity for improving the linear forms of spillways. Also, it was judged to be necessary improving load pressure and establishing protective structures at the riverbed grounds of downstream channels.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.401-404
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• 2008

The vegetation in the surrounding area of river is a primary factor to increase water level during flood. The influence of vegetation on the river flow in a bank has been investigated by using a hydraulic experiment. For a hydraulic experiment square-shaped piers are used as a model of unsubmerged rigid vegetation in a open channel. For fully developed uniform flows, the water elevation of the experiment was measured as varying the interval of piers and the porosity which presents the fraction of water flowing area in the cross-sectional area. The Manning's roughness coefficient, which implicates energy losses due to the vegetation, was obtained by using the experimental data. As a result, the energy losses were varied when the distance of piers and the porosity of area were changed, and the Manning's coefficient increased nonlinearly when a water elevation increased.

• Journal of Advanced Marine Engineering and Technology
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• 제29권3호
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• pp.251-259
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• 2005

A discrete time model reference adaptive control has been applied in order to compensate the nonlinear friction characteristics in a hydraulic proportional position control system. As nonlinear friction, static and coulomb friction forces are considered and modeled as dead zone and external disturbance respectively. The model reference adaptive control system consists of a cascade combination of the dead zone. external disturbance and linear dynamic block. For adaptive control experiment. the DSP(Digital Signal Processor) board has been interfaced the hydraulic proportional position control system. The experimental results show that the MRAC(Model Reference Adaptive Control) for compensation of static and coulomb friction are very effective.

• 한국해안·해양공학회논문집
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• 제34권1호
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• pp.1-10
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• 2022

본 연구에서는 저유속 조건에서도 발전이 가능한 수평 2열 쉬라우드 조류에너지 변환장치를 개발하였다. 쉬라우드 시스템의 형상을 결정하기 위해 3차원 수치모의 실험을 수행하였으며, 1/6 축소모형을 제작하여 수리모형 실험을 수행하였다. 수리모형 실험은 4가지 유속 조건하에서 수행하였으며, 각각의 실험 케이스별로 유속, 토크 및 RPM을 계측하였다. 수치모의 실험 결과, 노즐을 통과한 유속은 실린더에서 약 2~3배 유속이 증폭되는 것을 확인하였으며, 연장비가 2:1일 때, 가장 높은 유속 증폭율을 보였다. 또한 노즐과 실린더의 직경비는 1.5:1일 때 유속이 2.8배 증가하는 것으로 나타났다. 한편 수리모형 실험 결과, TSR이 1.75~2 일 때, 0.32~0.34의 출력 성능을 보이는 것으로 나타났다.

• Ocean and Polar Research
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• 제26권4호
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• pp.647-653
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• 2004

Experimental studies with 4.3m and enlarged 30m in height have been conducted to investigate the flow characteristics of solid-liquid mixture in a lifting pipe and to acquire the design data for sea tests that will be performed in the future. From the results, it was observed that the more the discharged volume fraction and the solid diameter increase, the more the hydraulic gradient increases. Also, the more the diameter of the lifting pipe increases, the smaller the friction loss, and consequently, the less pressure drop and hydraulic gradient. From the enlarged hydraulic pumping experiments, it was shown that the results of the experiments were matched with those of the numerical model previously developed. On the bases of these studies, we plan to conduct further experiments and validate the hydraulic pumping model.

• 한국수자원학회논문집
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• 제38권3호
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• pp.179-188
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• 2005

본 연구에서는 화북다목적댐을 대상으로 2차원, 3차원 수치모형실험이 수리모형실험과 더불어 설계자에게 유용한 해석도구로 사용될 수 있음을 보였다. 2차원, 3차원 수치모형으로 천수방정식을 지배방정식으로 하는 RMA2와 RANS를 지배방정식으로 하는 FLOW-3D 모형을 이용하였다. 수몰지역과 접근수로에서의 유황, 월류웨어의 방류능력, 월류부, 도류부, 감세지에서의 수면형상, 월류부에서의 압력분포에 대한 수치모의 결과를 수리모형실험 결과와 비교하였다. 비교 결과, 대부분의 경우에 수치모의 결과는 수리모형실험 결과를 잘 재현하는 것으로 나타났다 그러나, 감세지에서의 도수현상에 대한 수치모의 결과는 공기연행효과로 인해 수리모형실험 결과와 다소 차이가 발생하는 것으로 나타났다.

• 한국해안해양공학회지
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• 제19권2호
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• pp.179-182
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• 2007

본 연구에서는 연안침식방지와 친수공간을 제공하기 위한 목적으로 새로 개발된 환경친화형 친수호안블록의 성능을 검증하기 위하여 반사율과 안정성을 대상으로 수리모형실험을 실시하였다. 실험 결과 블록의 현장적용 가능성이 있음을 확인하였다.