• 한국항만학회지
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• 제14권1호
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• pp.115-124
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• 2000

This study is a suggest a measurement method of lateral displacement, which can be used to judge the stability of bridge abutment on soil undergoing lateral movement. The abutment of bridge on soft foundation makes lateral movement due to the settlement of back fill and lateral flow. To measure the displacement of such a abutment, there are a lot of indirect method for measurement such as survey of leveling or inclinometer gauge around the abutment. But all of them are not sufficient to confirm the ground behavior and measure the exact lateral behavior of structure. As making the structure and pile cooperatively by measuring the movement of lateral displacement, for measuring the abutment displacement precisely by using the inclinometer. In this work, we try to suggest efficient measuring method of abutment displacement and its application.

• International Journal of Automotive Technology
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• 제7권4호
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• pp.441-448
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• 2006

In-cylinder flows such as tumble and swirl play an important role on the engine combustion efficiencies and emission formations. The tumble flow, which is dominant in current high performance gasoline engines, is able to effect fuel consumptions and emissions under a partial load condition in addition to the volumetric efficiency under a wide open throttle condition. Therefore, it is important to optimize the tumble ratio of a gasoline engine for better fuel economy, lower emissions, and maximum volumetric efficiency. First step for optimizing a tumble ratio is to measure a tumble ratio accurately. For a tumble ratio measurement, many different methods have been developed and used such as steady flow rig, PIV, PTV, and LDV. However, it is not well known about the relations among the measured tumble ratios using different methods. The purpose of this research is to correlate the tumble ratios measured using three different methods and find out merits and demerits of each measurement method. In this research the tumble flow was measured, compared, and correlated using three different measurement methods at the same engine: steady flow rig; 2-dimensional PIV; and 3-dimensional PTV water flow rig.

• 대한기계학회논문집B
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• 제26권2호
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• pp.362-373
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• 2002

A stereoscopic PIV (SPIV) measurement system based on the translation configuration was developed and applied to the flow behind a forward-swept axial-fan. Measurement of three orthogonal velocity components is essential for flow analysis of three-dimensional flows such as flow around a fan or propeller. In this study, the translation configuration was adopted to calculate the out-of-plane velocity component from 2-D PIV data obtained from two CCD cameras. The error caused by the out-of-plane motion was estimated by direct comparison of the 2-D PIV and 3-D SPIV results that measured from the particle images captured simultaneously. The comparison shows that the error ratio is relatively high in the region of higher out-of-plane motion near the axial fan blade. The turbulence intensity measured by the 2-D PIV method is bigger by about 5.8% in maximum compared with that of the 3-D SPIV method. The phase-averaged velocity field results show that the wake behind an axial fan has a periodic flow structure with respect to the blade phase and the characteristic flow structure is shifted downstream in the next phase.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.777-781
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• 2001

An Altitude Engine Test Facility(AETF) was built at the Korea Aerospace Research Institute in October 1999 and has been being operated for altitude testing of the gas turbine engines of 3,000 Ibf class or less. The AETF has been calibrated using several engines such as J69 engine of Teledyne Co. as a facility checkout engine. Based on the test results, uncertainty analyses on the air flow rate and thrust were performed according to ASME PTC 19.1-1998. As the analyses showed that the level of uncertainty was not satisfactory over the whole operating envelop, several modifications of the facility and testing method were made in order to improve the measurement uncertainty. As a result, the uncertainty of the air flow measurement was improved by 0.1 % over all the test conditions, and the net thrust measurement by upto 3%. The improved measurement uncertainties of air flow and thrust are 0.68-0.73% and 0.4-1.3%, respectively.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.682-687
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• 2003

The variations of temperature and velocity fields in a Hele-Shaw convection cell (HSC) were investigated using a holographic interferometry and 2-D PIV system with varying Rayleigh number. To measure quasisteady changes of temperature field, two different measurement methods of holographic interferometry; double-exposure method and real-time method, were employed. In the double-exposure method, unwanted waves can be eliminated effectively using digital image processing technique and the reconstruction images are clear, but transient flow structure cannot be reconstructed clearly. On the other hand, transient convective flow can be reconstructed well using the real-time method. However, the fringe patterns reconstructed by the real-time method contain more noises, compared with the double-exposure method. Experimental results show a steady flow pattern at low Rayleigh numbers and a time-dependent periodic flow structure at high Rayleigh numbers. The periodic flow pattern at high Rayleigh numbers obtained by the real-time holographic interferometer method is in a good agreement with the PIV results.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1996년도 The Korean Institute of Navigation 1996년도 한·중 국제학술 심포지움 및 추계학술발표회 논문집
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• pp.31-36
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• 1996

It is important to measure the vehicle flow in controlling the traffic system. This report deals with a traffic flow measurement system using the differential spatial filters. This system can measure the velocity the length and height profile of the vehicle. The detector is located above the traffic lane. This provides the system with the following advantages : one is that each lane can be monitored without an influence of the other lanes the other is that the system construction is simple and can be set easily.

• 한국환경과학회지
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• 제7권6호
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• pp.793-801
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• 1998

In this study, the Dilution Method is used to measure river discharge through the hydraulic model test. the dilution method is divided into Constant-Rate-Infection Method and Slug-Injection Method in the river discharge measurement techniques. When the dilution method is applied in the hydraulic model flume, it is analyzed that the estimated error of constant-rate-injection method is less than that of the slug-in-jection method, and the result shows that floodflow analysis is more efficient than lowflow analysis as compared observed discharge with calculated discharge. The result of statistical error analysis shows that the constant-rate-injection method is appropriate technique for the measurement of the river discharge. Therefore, the dilution method among the river discharge measurement techniques can be applied for the river basin which can't be measured with current meter or unsteady-flow regime in the urban-small drainage or hydraulic structure equipment area and can be obtained more exact results than any other discharge measurement techniques.

• 한국정보통신학회논문지
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• 제16권12호
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• pp.2619-2627
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• 2012

전자 부자 흐름 패턴 시스템은 위치 측위 기술과 여러 가지 통신 기술을 이용하여 원격에서 부자의 위치를 모니터링 함으로써 하천의 유량을 예측할 수 있다. 현재 자연하천의 흐름 패턴을 분석하기 위해 여러 형태의 수동 부자들이 사용되고 있다. 수동 부자를 이용한 유량 측정은 유량을 측정하기위해 거리와 시간을 직접 측정한 후 이것을 이용한다. 이러한 방법은 측정방법과 정확한 유량 측정 측면에서 효율적이지 못하다. 이러한 문제를 극복하기 위해 본 연구진은 CDMA, GPS 그리고 2.4GHz기반의 RF모듈을 이용하여 전자부자를 설계 및 구현했다. 그리고 전자부자의 위치정보와 흐름 패턴 정보를 알기 위한 모니터링 시스템을 설계 및 구현하였다. 더불어 배터리로 동작하는 전자부자에서 짧은 life cycle은 전자부자를 이용한 흐름 패턴 시스템에서의 효용성을 떨어뜨린다. 이를 극복하기 위해 전자부자 흐름 패턴 시스템의 전자부자를 위한 전원 절약 기법을 설계하였다.

• 설비공학논문집
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• 제17권4호
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• pp.355-363
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• 2005

A novel method for simultaneously measuring the fluid velocity and the large particle velocity in a particle-containing fluid flow is developed in this study. In this method, the fluid velocity and the large particle velocity are measured by PIV and PTV, respectively. The PIV and PTV images are obtained from the same flow images. Since a PIV result represents the average displacement of all particles in an interrogation area, it will include an error caused by the relative displacement between the large particles and the fluid. In order to reduce the false influence of large particles on the PIV calculation, the mean brightness of small PIV particle images is substituted to the locations of large particles in the PIV images. The simulation results showed that the new method significantly reduces the PIV error caused by the large particles even at the case where the large particles occupy area fraction as large as $20\%$ of the full image.

• Journal of Advanced Marine Engineering and Technology
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• 제36권1호
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• pp.185-194
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• 2012

비교적 접근이 용이한 육상 및 천해에서 석유의 생산은 이미 완료되었거나 대부분이 진행 중이기에 석유 생산 지역이 점차 심해로 확장되고 있다. 심해와 같은 저온환경에서 석유생산이 이루어지면 석유의 부존환경과 다른 온도와 압력에 노출되어 생산시스템에 다양한 고형물이 집적되어 석유가 안정적으로 생산되지 못하게 하는 유동안정성 확보 문제가 발생할 수 있다. 고형물 중 왁스는 온도에 민감하기 때문에 왁스의 집적을 예측하고 제어하기 위해서는 오일 내 왁스가 석출되기 시작하는 온도인 왁스생성 온도의 정확한 측정이 요구되나 표준화된 측정법이 존재하지 않아 다양한 방법이 제안되고 있는 실정이다. 이 연구에서는 점도측정법, 시차주사열량법, 필터막힘점측정법, 압력필터측정법을 적용하여 불투명 오일의 왁스생성온도를 측정하고, 이를 검증하기 위해 고형물생성유도장치와 가스크로마토크래피를 이용하였다. 이 연구결과를 통해 오일특성에 따른 왁스생성온도 실험법을 체계화한다면 불투명 오일의 왁스생성온도 측정법 표준화하는데 주요자료로 이용할 수 있어 왁스에 의한 유동안정성 확보 문제를 예측하고 해결하는데 활용될 수 있을 것이다.