• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.2
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• pp.131-136
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• 2008

The characteristics of the flowfields around two circular cylinders in various arrangements were investigated by PIV. In tandem arrangement, the Strouhal numbers measured in the rear region of the cylinder of wake side were decreased with the space ratios, the flow between two cylinders was almost stagnated and the closer to upstream cylinder, the larger the width of the stagnated region was. The direction of vortex between two cylinders was opposed each other with the small difference(${\alpha}$=${\pm}1.0^{\circ}$) of the attack angle . In side by side arrangement, the flow velocity between two circular cylinders were increased with the space ratios.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.3
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• pp.87-95
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• 2002

원주의 항력 감소와 원주 주위 유동의 제어에 대하여 실험적으로 연구하였다. 원주 주위 유동을 제어하기 위하여 작은 제어봉을 원주 전방에 설치하였다. 실험시 원주 직경(D=30mm)에 기초한 레이놀즈수는 $Re=2 {/times} 10^4$이었다. 제어봉의 직경(d)은 4mm, 5mm, 6mm, 7mm로 변화시켰으며, 원주와 제어봉 사이의 거리(L)를 조절하면서 원주의 표면압력분포와 후류속도를 측정하였다. 제어봉으로부터의 와 유출이 사라지는 임계거리 (critical distance) $ L_C$는 $ L_C$ /D=1.5+0.83d이었는데, $ L_C$를 전후로 유동특성과 항력값이 크게 바뀌었다. 특히 원주와 제어봉 사이의 거리가 임계거리보다 짧은 경우에는 항력이 감소하다가 $ L_C$보다 크게 되면 증가하는 경향을 보였다. 제어봉의 직경이 d/D=0.233인 경우, L/D=2.013의 조건에서 원주는 약 29%의 항력 감소를 보였고, 전체 항력은 L/D=1.833조건에서 약 25% 항력이 감소하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.7
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• pp.1381-1390
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• 1992

This paper presents a dynamic characteristics of flow induced vibration of circular cylinder set with inclined angle against flow direction. The effect of the cylinder bounded by spiral fin and wire on the damping of flow induced vibration is investigated, i.e., inclined angle, spiral pitch angle and number of spiral thread are studied. As the results, the cylinder with spiral fin is most effective for the damping. Also the cylinder bounded by pitch angle 50.deg. and 2 spiral thread is most effective.

• KOMUNHWA
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• no.61
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• pp.165-191
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• 2003

White Porcelain kiln sites confirmed in Wonju are a total of 12: Chijeong-Myon, Pandea-ri, Guyre-lri etc. in the early period of Chosun Dynasty, and Guyre-2ri and Songok-ri etc. There were several reasons why Wonju was the major kiln site during the early

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.2
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• pp.264-270
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• 2011

The Characteristics of the flowfield around three circular cylinders in tandem arrangement was investigated by PIV. Strouhal numbers, vorticity, velocity vectors and velocity profiles were observed at centre-to-centre space ratios of P/D=1.25~3.75, and Reynolds number of Re=$3.0{\times}10^3{\sim}5.0{\times}10^3$. As the results the Strouhal numbers measured in the rear region of 3rd the cylinder were distinguished three kind of regions with the space ratios and The flow pattern in the wake of each cylinder was different according to these regions. The time averaged flow at region of each cylinder was almost stagnated and the size of the stagnated region was small in order of 1st, 2nd and 3rd cylinder. The direction of vortex at the front and rear region of 2nd cylinder was opposed each other with the small difference(${\alpha}= {\pm}5^{\circ}$) of the attack angle ${\alpha}$.

• Progress in Medical Physics
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• v.8 no.1
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• pp.37-45
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• 1997

The present work is determine to the dose distribution reduced by the insertion of a shielded into a vaginal cylinder around a $\^$60/CO source in brachytherapy, and to the source calibration. It was investigated by measuring the relative dose around a 2.5cm diameter shielded vaginal cylinder in a polystyrene phantom by use of a ionization chamber. Measurements were made with the cylinder unshielded and 0.55cm thick 90$^{\circ}C$ lead shields inserted. Also, the dose distribution compared measurement value with calculation value according to the device manufacturer and the multiple-divided dose tables. A reduction in dose was observed on the unshielded side of the cylinder which increased with distance from the source and it does 4.4％ within 1cm from the surface of the cylinder. On the shielded side of the cylinder, the dose at the surface is reduced to about 20.4％ of its value without the shield. The effective attenuation factor entered for the 90$^{\circ}C$ lead shielded cylinder was average 0.2 in a $\^$60/CO moving source. In comparision with the dose calculation mathods, the multiple-divided dose tables are difference less than ${\pm}$4.1％ with measured data in a $\^$60/Co source.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.198-204
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• 2016

The characteristics of the flow field of a circular cylinder having a small vertical plate at the upstream side are investigated by measuring the fluid force on the circular cylinder and by visualizing the flow field using particle image velocimetry. The experimental parameters are the width ratios (H/B = 0.2-0.6) of the vertical plates to the circular cylinder's diameter, and the gap ratios (G/B = 0-3) between the circular cylinder and the vertical plate. The drag reduction rate and Strouhal number of the circular cylinder increased and then decreased with G/B in the case of the same H/B. The drag reduction rate increased with H/B in the case of the same G/B. In the case of a circular cylinder having a small vertical plate, the stagnation regions are represented on the upstream and downstream sides of the circular cylinder, and the size of that region on the upstream side increased with H/B.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.428-434
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• 2021

To study whether the area under the cultivation of Italian ryegrass (IRG) has increased with rise in global temperatures, we investigated the effects of climatic variables on seed productivity in different parts of Gangwon-do, South Korea. Specifically, IRG was cultivated in the western (Gangneung), central (Wonju), and northern (Chuncheon) parts of Gangwon-do. The heading date of IRG in Gangneung was earlier than that in the other regions. Moreover, the values of agronomic traits, including spikelets per spike, grains per spike, and thousand-grain weight, were lower in Chuncheon. However, there were no differences spikelets per spike and grains per spike between Wonju and Gangneung. Additionally, the thousand-grain weight and seed production were higher in Gangneung. Statistical correlation analysis between climatic variables and agronomic traits revealed that the mean daily minimum temperature was positively correlated with seed formation-related traits in April and seed maturity-related traits in May. In the light of rising minimum temperatures in Gangwon-do, Gangneung, Chuncheon and Wonju are suitable areas for IRG cultivation with optimal seed productivity.

• Journal of Korean Physical Therapy Science
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• v.8 no.2
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• pp.1047-1050
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• 2001

이 연구의 목적은 전완 원주와 악력과의 상관관계를 알아보는 것이다. 오른손잡이 여성 30명이 이 연구에 참여하였으며, 연구의 대상자의 평균 연령은 31.0세였다. 전완 원주는 척골의 주두와 경상돌기의 1/2 지점과 근위 3/4 지점에서 줄자를 이용하여 측정하였다. 악력은 미국 수부 치료사 협회의 기준에 의하여 Jarmar dynamometer를 사용하여 측정하였다. 통계학적 분석은 피어슨 상관 관계 계수를 이용하여 상관관계를 조사하였다. 전완 두 지점에서 측정된 원주와 악력간에는 낮은 상관관계를 나타내었다(r=.02. p=.921; r=.02, p=.928). 연구 대상자 30명 중 정기적으로 상체 운동을 하는 18명의 연구 대상자들의 전완 두 지점에서도 낮은 상관 관계를 나타내었다(r=.16, p=.521: r=.18, p=.468). 본 연구의 결과는 선행된 다른 연구 결과와는 상이하게 높은 상관관계를 나타내지 않았다. 그 이유로는 본 연구에서 악력에 영향을 주는 여러 가지 요소들(신체 유형, 운동 습관. 직업 피하 지방성분, 유전적 요소 등)의 측정이 고려되지 않았고. 연구 대상자의 수(n=30)가 적었다는 점을 들 수 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.278-278
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• 2019

본 연구의 목적은 수위조건에 따른 댐체의 방류능력을 검토하는 것이 주목적으로 수리모형실험을 통한 수위-유량곡선을 제시하고 이론식으로 도출된 방류량 산정값과의 결과를 검토하는 것이다. 원주천댐은 강원도 원주시 판부면 신촌리 일원에 설치되는 콘크리트 중력식 댐으로 댐길이는 210.0m 이며, 댐높이는 45.5m, 댐마루고는 EL. 239.0m 이다. 홍수시 방류설비로는 21m 길이의 무문식 2열 여수로로 이루어져 있다. 본 연구를 위해 제작된 원주천 댐모형은 수평축척(LH) 1/60, 연직축척(LV) 1/60, 왜곡도 1을 갖는 정상모형으로 제작되었다. 방류능 검토실험은 여수로의 방류량을 검토하는 것으로 수위와 방류량과의 관계를 계측을 통해 곡선으로 제시하는 것이다. 수위는 저수지 상류부 수위(원주천댐으로부터 150 m 상류지점)를 측정하여 수위별 방류량을 계측하였다. 유량의 경우 방류량값의 정확도 향상을 위해 관유량계와 삼각위어를 동시에 사용하여 측정하였다. 수리모형실험 결과 원주천댐의 수위-방류량 곡선은 그림 1과 같이 산출되었다. 이러한 결과를 토대로 원주천댐 설계시 사용되었던 자료를 비교하여 보았다. 원주천댐의 수위별 방류량은 미개척국(USBR)의 'Design of Small Dams'와 "댐 설계기준 해설(2011, 한국수자원학회)"에서 제시한 방법으로 방류량을 산정한 것으로 이들 두 자료를 비교한 자료는 그림 2와 같다. 실험결과 계산식과 수리모형실험을 통해 계측된 방류량은 큰 차이를 보이지 않는 것으로 나타났다. 이러한 결과로 보았을 때 계산식으로 산정된 수위-유량관계식은 충분히 댐운영에 적용할 수 있는 기초자료로 충분할 것으로 판단된다.