• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1999년도 춘계학술발표회요약집
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• pp.158-158
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• 1999

• 한국습지학회지
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• 제13권2호
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• pp.307-317
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• 2011

최근에 홍수조절 기능으로써 강변저류지 조성에 대한 관심이 증가하고 있다. 따라서 본 연구에서는 수리실험을 이용한 강변저류지의 홍수조절효과를 분석하였다. 강변저류지의 홍수조절효과를 분석하기 위해 개수로 실험장치를 이용하였으며, 측방구조물로는 횡월류 위어를 이용하였다. 수리실험 결과 횡월류 위어 설치 지점을 기준으로 평균유속과 유량이 감소하는 것으로 나타났다. 또한 수리실험 결과의 검토를 위해 HEC-RAS 모형을 이용하여 실험결과와 모형의 모의 결과를 비교하였다. 그 결과 수리실험 결과와 모형의 모의 결과가 유사한 것으로 분석되었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 추계학술대회 논문집
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• pp.177-181
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• 1992

For this study, a new hydraulic control unit which designed in compact compared to the currently manufactured hydraulic control unit for ABS has been introduced and its experimental model has been made. Based on the basic principle as ABS using braking force characteristics against slip ratio of tire, half car model bench tester were designed and made to make an analysis of braking effect of the new hydraulic control unit. Experiment for slip ratio characteristics of tire has been carried out using half car model bench tester and with the results of this experiment and control experiment of the new hyraulic control unit, the experiment result of the characteristics of tire and control experiment were compared to find out their correspondence. And furthermore, slip ratio characteristics of the new hydraulic control unit has been studied based on the experiment result of slip ratio characteristics of tire through simulation and compared with experiment result.

• International Journal of Automotive Technology
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• 제6권1호
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• pp.65-70
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• 2005

Pressure ripples, which are inevitably generated by a fluctuation of flow rate caused by a pump mechanism, include noises and vibrations in hydraulic pipeline. These noises and vibration deteriorate the stability and accuracy of hydraulic systems. The accumulator and hydraulic attenuator are normally used to reduce the pressure ripples. In this study, a parallel line is introduced to the hydraulic pipeline for the hydraulic system with a bent-axis piston pump as a method to reduce the pressure ripples. The dynamic characteristics of the hydraulic pipeline with a parallel line are analyzed by a transfer matrix in the frequency domain. The usefulness of the hydraulic pipeline with a parallel line was ascertained by experiment and simulation. The results from the experiment and simulation show that the hydraulic pipeline with a parallel line were effective in reducing the pressure ripples.

• International Journal of Fluid Machinery and Systems
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• 제8권4호
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• pp.318-326
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• 2015

A valve-less electro-hydraulic servo steering device (short: VSSD) for ships was chosen as a study object, and its mathematic model of hydraulic shock was established on the basis of flow properties and force balance of each component. The influence of system structure parameters, changing rate of motor speed and external load on hydraulic shock strength was simulated by the method of numerical simulation. Experiment was designed to test the hydraulic shock mathematic model of VSSD. Experiment results verified the correctness of the model, and the model provided a correct theoretical method for the calculation and control of hydraulic shock of valve-less electro-hydraulic servo steering device.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.1818-1822
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• 2008

여수로와 같은 3차원 수리구조물을 설계하고 수리현상을 조사하거나, 형상 및 안정성을 파악하기 위해서는 일반적으로 수리모형실험을 통하여 실제 현상을 모의하는 경우가 많다. 그러나 수리모형실험을 하기 위해서는 많은 시간과 비용 및 공간이 필요하며 실제 수리구조물을 축소시켜 측정하는 것은 대단히 어렵고 표면장력 등이 실험결과에도 상당한 영향을 미칠 수 있으며 다양한 경우의 실험은 현실적으로 불가능하다. 따라서, 수치해석을 통하여 적정한 초기결과를 도출할 필요성이 있으며, 이를 통하여 수리모형실험의 대상을 결정하고 결과를 비교한다면 경제적이고 합리적인 수리구조물의 설계와 평가가 가능하다. 본 연구에서는 최적의 여수로를 설계하기 위하여 월류형 여수로를 대상으로 수치해석을 수행하였고, 수리모형실험에 대한 실험적인 접근을 통하여 수리적 조건을 향상시킬 수 있는 보다 나은 설계안을 제시하였다. 이러한 수리모형실험 계측결과를 통하여 개선된 수리구조물 설계안을 제안하였고, 개선된 설계안에 대한 개선효과를 조사하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.137-137
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• 2000

In this research. we developed Tire Roller Prototype which is operated hydraulic transmission system. For develop the theoretically computer aided system, we practiced the simulation of hydraulic system and dynamic modeling and will compare with the experiment results of Tire Roller Prototype. We conceptualize the new hydraulic system and derive the equations of motion for dynamic analysis. Finally, we will design the controller, which can manage the hydraulic circuit of servo mechanism system. We define new hydraulic system and integrate modeling of Tire Roller through simulation of h\ulcornerdraulic system and design of controller. From above procedure. Hydraulic transmission system characteristics and target performance can be investigated. To follow the required performance, we select the parts of Tire Roller. We manufactured the prototype of Tire Roller, and will install the equipment for experiment.

• 한국해양공학회지
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• 제36권5호
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• pp.326-339
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• 2022

Recently, not only Korea but also the world has been suffering from problems related to coastal erosion. The hard defense method has been primarily used as a countermeasure against erosion. However, this method is expensive and has environmental implications. Hence, interest in other alternative methods, such as the eco-friendly vegetation method, is increasing. In this study, we aim to analyze the hydraulic characteristic of submerged rigid vegetation according to the cross-sectional change through a hydraulic experiment and numerical simulation. From the hydraulic experiment, the reflection coefficient, transmission coefficient, and energy dissipation coefficient were analyzed according to the density, width, and multi-row arrangement of the vegetation zone. From numerical simulations, the flow field, vorticity distribution, turbulence distribution, and wave distribution around the vegetation zone were analyzed according to the crest depth, width, density, and multi-row arrangement distance of the vegetation zone. The hydraulic experiment results suggest that the transmission coefficient decreased as the density and width of the vegetation zone increased, and the multi-row arrangement condition did not affect the hydraulic characteristics significantly. Moreover, the numerical simulations showed that as the crest depth decreased, the width and density of vegetation increased along with vorticity and turbulence intensity, resulting in increased wave height attenuation performance. Additionally, there was no significant difference in vorticity, turbulence intensity, and wave height attenuation performance based on the multi-row arrangement distance. Overall, in the case of submerged rigid vegetation, the wave energy attenuation performance increased as the density and width of the vegetation zone increased and crest depth decreased. However, the multi-row arrangement condition did not affect the wave energy attenuation performance significantly.

• 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.

• 한국농공학회지
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• 제17권3호
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• pp.3833-3839
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• 1975

The object of this experiment is to find out some flow characteristics of water through sand layer, to prevent moving sands in the filters of the fill Dam, infiltration gallery, well and Deversion Weir. This experiment was accomplished with different particle Sizes of Six Samples and different hydraulic gradient. The results obtained are Summarized as follows. 1. The critical hydraulic gradients for laminar flow was found to be between 1 and 2 when the sand used had the effective diameter, D10 of between 0.18cm and 0.45cm. 2. The critical hydraulic gradients for different particle sizes of sands were varied considerably. 3. There was a negative correlation between critical hydraulic gradient and critical Velocity, and between effective particle diameter D10 and critical hydraulic gradient respectively. 4. In spite of relatively small variation of void ratio of sands used, the values of the coefficient of permeability varied considerably. There was a negative correlation between coefficient of permeability and void ratio.