• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.855-859
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• 2007

It is essential to obtain accurate and highly reliable streamflow data for water resources planning, evaluation and management as well as design of hydraulic structures. A new discharge estimation method, which is named 'non-dimensional velocity distribution and index-velocity method,' was proposed in this research. This method showed very close channel discharges which were calculated with the exiting velocity-area method. When velocity-area method is used to estimate channel discharge, it is required to observe point velocities at every desired point and vertical using a current meter like Price-AA. However 'non-dimensional velocity distribution and index-velocity method' is used, it become optional to observe point velocities at every desired point and vertical. But this method can not be applied for the cases of very complex and strongly asymmetric channel cross-sections because non-dimensional velocity distribution by entropy concept may be quite biased from that of natural rivers.

• 한국수자원학회논문집
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• 제41권6호
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• pp.575-585
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• 2008

수자원의 계획 평가 관리 및 수공구조물의 설계를 위해서는 정확하고 신뢰성 높은 유량 자료가 필수적이다. 본 연구에서는 Chiu의 유속분포와 최대유속 추정을 이용하여 하천유량을 계산하는 새로운 방법을 제시하였다. 기존 면적유속법과 비교 검토한 바, 본 연구에서 개발한 방법은 기존 유속면적법과 매우 유사한 하천유량을 보였다. Price-AA를 이용하여 유속을 측정할 경우 측선의 수심에 따라 정해진 지점에서 유속을 측정하여야 하는데, 본 연구에서 제시한 방법을 이용하면 임의의 측선과 측점에서 유속을 측정하여도 정확한 유량계산이 가능하다. 그러나 흐름 단면이 매우 복잡하거나 좌우의 비대칭성이 심한 경우에는 엔트로피 개념의 Chiu의 유속분포가 실제 자연하천의 흐름분포에서 멀어지고 유량산정에 Chiu의 유속분포의 정확도가 떨어지기 때문에 본 연구에서 제시한 방법을 적용하기 어렵다.

• 소음진동
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• 제9권5호
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• pp.943-948
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• 1999

This paper proposes a feasible and effective method for measuring the mechanical-acoustic transfer function by the application of equivalent area and velocity transfer function, a manifestation of the vibro-acoustical reciprocity principle. On the contrary to the volume velocity used in traditional method, the equivalent area is a peculiar raidation characteristics of sound sources and not influenced by any input signal for driving sound source. This invariant property of equivalent area can get rid of boresome works to measure the volume velocity of a sound source every time the driving signal is changed. Moreover, this method has a remarkable advantage to use a general loudspeaker as an accoustic exciter without the assumption of point source and can be applied to all kinds of sound sources even if they are not omni-directional sources.

• 건축역사연구
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• 제24권5호
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• pp.41-48
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• 2015

Quantitative analysis of termites damage is important in terms of conservation and maintenance of wooden cultural heritage buildings, because termites makes cavities and decreases the section area of wooden structural members. The purpose of this study is to forecast the range and spread of termites damage in the wooden structural members by using ultrasonic pulse velocity method. Ultrasonic pulse velocity has been used as one of non-destructive test to analysis the internal defect by using difference velocity between medium material and cavity. This method would be effective to analysis termites damages. From the result of the ultrasonic velocity test, the loss rate of area effected by termites damage had a strong correlation with ultrasonic velocity. And it is possible to predict the loss rate of area from by termites damage by using regression equation in the case of structural member of fine tree.

• 한국수자원학회논문집
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• 제38권10호
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• pp.811-824
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• 2005

ADCP는 음파의 도플러 효과를 이용하여 하천을 횡단하면서 단시간에 유속과 유량을 측정할 수 있는 장비이다. 본 연구는 현장 하천에서 ADCP를 이동식으로 운용하여 측정한 유속, 유량 자료를 동일한 지점에서 측정한 유속-면적법과 비교하여 ADCP를 이용한 유속, 유량 자료의 특성을 살펴볼 목적으로 수행되었다. ADCP에 의해 측정된 수심 분포는 직접 측심에 의해 측정한 수심 분포와 거의 일치하였다. ADCP로 측정한 유속은 순간적이므로 개별 연직유속분포는 시간평균한 유속-면적법 자료와 차이가 있었으나 유속 측선의 좌우에 근접한 자료를 공간적으로 평균할 경우 그 차이는 감소하고 유사한 유속 패턴을 나타내었으며, 왕복하여 반복한 측정 자료를 평균할 경우에도 시간평균한 자료와 비슷한 연직유속분포를 나타내었다. 수평유속분포의 경우 ADCP의 개별 자료 및 이를 중간단면적법에 해당하는 구간 하폭만큼 평균한 자료 역시 유속-면적법 자료와 잘 일치하는 양상을 나타내었다. 유량의 경우 한 지점에서 수 회 이상 평균한 값은 유속-면적법과 비교하여 $0.1\%{\~}9.3\%$의 차이가 나는 것으로 조사되었으며, 반복 측정 횟수를 늘릴 경우 유속-면적법 대비 오차가 감소하는 것으로 나타났다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.385-391
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• 2000

Velocity method was supposed by Parkin et al.(1985) in order to supplement previous log t and (equation omitted) method. This study was to present the method for estimating the horizontal coefficient of consolidation by using velocity method which was based on the Barren's equation. Velocity method throughly eliminated not only settlement curve which had shape with difficulty in evaluating coefficient of consolidation but also the effect of unknown intial compression, the secondary consolidation and occurrence of unknown point by using velocity instead of settlement. The purpose of this study is to investigate its application in field. Velocity method was used in obtaining horizontal coefficient of consolidation in Kyung-gi area. Horizontal coefficient of consolidation using velocity method was calculated and compared with log t method, √t method Magnan & Deroy's method, Bergado's method.

• 한국분무공학회지
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• 제3권1호
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• pp.27-33
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• 1998

Correlations of drop size and velocity in a spray from the disintegration of liquid jet and liquid film from an internal mixing twin-fluid atomizer, were determined by phase Doppler method. The distribution pattern of Sauter mean diameter(SMD) in a spray was changed by a behavior of liquid flow. As smaller droplets became faster and slower easily by the surrounding conditions, the correlation between drop size and mean velocity was found to be varied as next 3 steps; firstly smaller droplets have a higher mean velocity at the area near atomizer, droplets have almost the same mean velocity and finally larger droplets have a higher mean velocity at the area far from an atomizer.

• 지질공학
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• 제4권3호
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• pp.333-341
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• 1994

Ray Method와 관측지진 자료에 의해서 지각구조 상부 Mantle을 연구하면서 저속도층이 탐지되었다. 우리는 한반도에서 부곡 온천 지역과 추가령 지구대를 통과하는 P파와 S의 도착 시간 지연을 관측했다. 현재 지열 탐사는 이 지역이 심부 저속도 물체는 "지연 암영"이라고 불리우는 높은 지열이상을 설명 해주고 있다. 우리는 하부지각의 부분 용융에 기인한 저속도 물체의 가설을 하부지각의 이차원 비등질 모델의 속도변화가 있음을 Ray Method(Cerveny and Psencik, 1983)에 의해서 분석 하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.154-154
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• 2021

Since the development of Bubble Image Velocimetry (BIV) technique as the complementary technique of Particle Image Velocimetry (PIV), the application of digital imaging technique in the field of hydraulic and coastal engineering increased rapidly. BIV works very well in multi-phase flow (air-water) flows where the PIV technique doesn't. However, the velocity field obtained from BIV technique often resulted in a velocity vector on the outside of the flow (false velocity) since the Field of View (FOV) usually not only cover the air-water flow but also the area outside the flow. In this study, a simple technique of post processing velocity field was developed. This technique works based on the average of the pixel value in the interrogation area. An image of multi-phase flow of wave overtopping was obtained through physical experiment using BIV technique. The velocity calculation was performed based on the similar method in PIV. A velocity masking technique developed in this study then applied to remove the false velocity vector. Result from non-masking, manually removed and auto removed false velocity vector were presented. The masking technique show a similar result as manually removed velocity vector. This method could apply in a large number of velocity field which is could increase the velocity map post-processing time.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1340-1352
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• 2008

In this study, S-wave velocity range is gauged in every field test method at the total 5 locations in the marine deposits in Incheon area. field test method is accomplished the SPT(Standard Penetration Test), CPT(Cone Penetration Test), SPS(Suspension PS Logger), SCPT (Seismic Cone Penetration Test) and so on. The S-wave velocity of SCPT in the downhole test method is measured lower than SPS logger at the N value > 15 range. But at the N value < 15 range, SPS logger and SCPT result is measured same. In this result, although the soil strength of the downhole test method increased, the rate of S-wave velocity is tend to be slowed. This result shows that the downhole test is difficult to apply at the place that the intensity of soil is more extreme and harder soil. And it shows that the existing Imai(1982) type that is mostly used within the country is not suitable for the marine deposits. Thus, the empirical formula that can show the range of S-wave velocity in each N value for domestic soil is needed.