합성얼음과 냉동얼음을 사용한 쇄빙선의 추진 성능 비교 연구

김문찬(Moon-Chan Kim),임태욱(Tae-Wook Lim),조준철(Jun-Cheol Jo),전호환(Ho-Hwan Chun),왕정용(Jungyong Wang) 한국해양공학회 2009 韓國海洋工學會誌 Vol.23 No.1

This paper reports on experimental investigations of self-propulsion performance with syntehtic (model) ice and refrigerated ice, which were conducted in a typical towing tank and ice tank, respectively. The main purpose of this research was to find the correlation between the self-propulsion performance with synthetic ice in a typical towing tank and that with refrigerated ice in an ice tank. The different stresses between the syntehtic ice and refrigerated ice influenced the self-propulsion performance due to different ice and propeller interactions. A further study on the ice property variation for a self-propulsion performance comparison is to be conducted in the near future.

중형 공동수조에서의 프로펠러 단독특성에 대한 위벽효과 보정 연구

서성부(Sung-Bu Suh),김기섭(Ki-Sup Kim) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회지 Vol.34 No.4

공동수조와 예인수조에서의 프로펠러 단독특성 차이를 보정할 수 있는 위벽효과 연구를 수행하였다. 우선 공동수조의 실험에서 프로펠러의 상류가 아닌 작동 평면 위치에서 계측된 유속을 프로펠러 전진속도로 정의할 경우, 위벽효과의 수정 량 및 단독특성차이가 현저히 줄어드는 것을 확인하였다. 다음으로 양력판 이론에 의한 단독특성 계산을 통해, 프로펠러 평면에서의 위벽효과를 구하고 앞의 결과에 추가적인 보정을 수행하였다. 그 결과, 예인수조에서의 단독특성과 더욱 더 좋은 일치를 보여 주는 것을 확인하였다. This paper studies the differences due to the wall effect in propeller open water(POW) characteristics tested in a towing tank and in a medium size cavitation tunnel(CT). When the advanced velocity of the propeller is defined as the flow velocity measured in the plane of propeller, POW characteristics resulting from CT has a better relationship with them of towing tank. To obtain the wall effect in the propeller plane, numerical computation using the lifting panel theory is performed with and without the wall around a propeller. Then, POW results in CT are corrected based on the wall effect from numerical results. The POW results obtained from this procedure show a better agreement with the experimental results in the towing tank.

일반 수조에서의 합성 얼음의 밀도변화에 따른 쇄빙선의 저항특성 연구

임태욱(TAE-WOOK LIM),김문찬(MOON-CHAN KIM),전호환(HO-HWAN CHUN) 한국해양공학회 2008 韓國海洋工學會誌 Vol.22 No.5

This paper deals with the experimental works for the correlations of ice resistance for icebreaker with synthetic(model) ice in general towing tank and with refrigerated ice in ice tank. In order to find out the correlation, the density variation is mainly focused in the present study. The model of Terry-Fox ice breaker has been used for the present correlation study because many data are available to be compared. According to the increase of density, the correlation becomes better quantitatively as well as qualitatively. Other parametric studies such as an ice size, a friction coefficient, a bending moment, etc., are also expected to be carried out to have better correlation in a near future. This research could be the basis for the possibility of resistance test using a synthetic ice in a general towing tank instead of an expensive ice tank.

Uncertainty assessment for a towed underwater stereo PIV system by uniform flow measurement

Han, Bum Woo,Seo, Jeonghwa,Lee, Seung Jae,Seol, Dong Myung,Rhee, Shin Hyung The Society of Naval Architects of Korea 2018 International Journal of Naval Architecture and Oc Vol.10 No.5

The present study aims to assess test uncertainty assessment method of nominal wake field measurement by a Stereoscopic Particle Image Velocimetry (SPIV) system in a towing tank. The systematic uncertainty of the SPIV system was estimated from repeated uniform flow measurements. In the uniform flow measurement case, time interval between image frames and uniform flow speed were varied to examine the effects of particle displacement and flow around the SPIV system on the systematic standard uncertainty. The random standard uncertainty was assessed by repeating nominal wake field measurements and the estimated random standard uncertainty was compared with that of laser Doppler velocimetry. The test uncertainty assessment method was applied to nominal wake measurement tests of a very large crude oil carrier model ship. The nominal wake measurement results were compared with existing experimental database by other measurement methods, with its assessed uncertainty.

외해 양식장 콘크리트 부유식 방파제 개발에 관한 연구

최군환,김미정,장기호,전제천,박정준 한국해양공학회 2019 韓國海洋工學會誌 Vol.33 No.6

The ecological changes in the ocean due to the drastic global warming require that action be taken to sustain the productivity of fisheries. Proper ocean facilities could help prevent the loss of the expenditures made on marine aquaculture and reduce the related compensation for various ocean conditions. The aim of this study was to develop a floating ocean wave-breaker using an eco-friendly concrete and conducting a site survey, a structural analysis, and a test of towing the tank. As a result, the wave at the fish farm would be reduced. The results of the holding power of anchors and the capability of moving the floating structures were considered in the design of the wave-breaker. The analyses of the material properties of concrete and the steel structures, as well as the CAPEX and OPEX analyses of the manufacturing and operation processes confirmed the superiority of the floating concrete wave-breaker. In particular, this study demonstrated that the concrete floating breakwater can protect the fish farm against typhoons and reverse-waves, thereby reducing losses of the fish.

Uncertainty assessment for a towed underwater stereo PIV system by uniform flow measurement

Bum Woo Han,Jeonghwa Seo,Seung Jae Lee,Dong Myung Seol,Shin Hyung Rhee 대한조선학회 2018 International Journal of Naval Architecture and Oc Vol.10 No.5

The present study aims to assess test uncertainty assessment method of nominal wake field measurement by a Stereoscopic Particle Image Velocimetry (SPIV) system in a towing tank. The systematic uncertainty of the SPIV system was estimated from repeated uniform flow measurements. In the uniform flow measurement case, time interval between image frames and uniform flow speed were varied to examine the effects of particle displacement and flow around the SPIV system on the systematic standard uncertainty. The random standard uncertainty was assessed by repeating nominal wake field measurements and the estimated random standard uncertainty was compared with that of laser Doppler velocimetry. The test uncertainty assessment method was applied to nominal wake measurement tests of a very large crude oil carrier model ship. The nominal wake measurement results were compared with existing experimental database by other measurement methods, with its assessed uncertainty.

Experimental study on kinetic energy conversion of horizontal axis tidal stream turbine

Seo, Jeonghwa,Lee, Seung-Jae,Choi, Woo-Sik,Park, Sung Taek,Rhee, Shin Hyung Elsevier 2016 RENEWABLE ENERGY Vol.97 No.-

<P><B>Abstract</B></P> <P>The present study aims to understand the energy conversion mechanism of a 100 kW horizontal axis tidal stream turbine by analyzing thrust, torque, and wake flow measurements. The scale ratio of the turbine model was 1/20 and model tests for power and wake measurements were conducted in a towing tank facility. Wake fields were measured by a towed underwater stereoscopic particle image velocimetry (SPIV) system. The chord-length based Reynolds number at 40% of the radius of the turbine ranged from 53,000 to 63,000 in the test conditions. The turbine model showed the highest power coefficient at a tip speed ratio (TSR) of 3.5, and the magnitude of power coefficient was 0.278. Three TSR conditions were selected for SPIV measurement after power measurement tests, representing heavy loading, highest efficiency, and light loading, respectively. In the wake field measurement results, conversion of kinetic energy of the turbine wake was investigated, decomposing it into effectively extracted work, loss due to the drag on the turbine system, kinetic energy of the time-mean axial flow, local flow structures, turbulence, and secondary flow loss. In high TSR conditions with a small angle of attack onto the turbine blade, the secondary flow loss was minimized.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Wake and force measurements of a HATST model were conducted in the towing tank. </LI> <LI> The measurements were characterized by a small blockage ratio and high Reynolds number. </LI> <LI> Energy conversion mechanism of a HATST was analyzed with measured data. </LI> <LI> Turbulence generation consumes only a small portion of the inflow kinetic energy. </LI> </UL> </P>

회류수조와 예인수조 시험결과의 상호관계의 실험적 연구

이귀주,라영곤 대한조선학회 2003 大韓造船學會 論文集 Vol.40 No.4

Model tests using 2.0m model of the series 60 form(= 0.6) were carried out in the Circulating Water Channel (CWC) in the Chosun University (CU, Korea) for the purpose of a correlative study with Towing Tank (TT). Resistance, propeller open water, self propulsion and wake survey tests were carried out and the results were extrapolated to the ship scale. These results were compared with the extrapolated ship values based on the model test of 7.0m model in the TT at the Korea Research Institute of Ships and Ocean Engineering (KRISO, Korea). The CWC test results were correlated with the results of the towing tank tests.

전산유체역학을 이용한 수중운동체 저항해석 및 예인수조에서의 저항시험 방법에 대한 고찰

박정훈(Jeonghoon Park),김성훈(Sunghoon Kim),정배균(Baegyun Jeong),김종순(Jongsoon Kim) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12

Flow Resistance is very important element in flight performance of underwater vehicle. Generally, We used the method of towing model in constant velocity and measuring force to obtain the resistance. However, resistance in real flight velocity of vehicle is calculated by applying theoretical prediction of surface vehicle resistance test, because of performance limit of towing tank(for example, towing velocity Etc.). In this paper, we calculated resistance of underwater vehicle by using CFD(Computational Fluid Dynamics), and checked the reliability of simulation model, comparing to experiment results. In addition, resistance simulation results by applying towing tank method were compared to those by applying real flight velocity, and we verified feasibility of prediction in towing tank test.

풍동과 예인 수조를 이용한 터빈 성능 비교 시험

강정민(Kang, Jung-Min),이영호(Lee, Yeong-Ho),이규찬(Lee, Kyu-Chan) 한국신재생에너지학회 2011 신재생에너지 Vol.7 No.4

The objective of this paper is to suggest a new method of a wind turbine performance test. The performance test of a wind turbine is generally carried out in a wind tunnel. The test needs not only a high-accuracy measuring system but also durable structure to withstand high speed turbine rotation and wind flow. Therefore, we tried turbine performance test using a towing tank to improve stability and reliability. Because a turbine rotates more slowly and generates more torque in the water than in the wind tunnel under similarity conditions. In this study, we developed turbine performance test systems and verified the turbine test method using a towing tank through comparing results of the wind tunnel and the towing tank test.