1. 서 론 국내외적으로 선박의 온실가스 배출량을 감축하기 위한 노력 이 활발히 이루어지고 있다. 특히, 국제해사기구(IMO)의 MEPC (Marine Environment Protection Committee)에서는 선박의 온 실가스 배출량을 줄이고자 선박 제조연비 지수(Energy Efficiency Design Index, EEDI) 및 에너지 효율 운항 지표 (Energy Efficiency Operational Indicator, EEOI)를 도입하여 이 에 대한 규제를 강화하고 있다. 이러한 분위기 속에서 정수 중 속도 성능 뿐만 아니라, 파랑 중 선박의 속도 성능에 대한 관심 이 높아져 가고 있지만, 아직까지 대부분의 파랑 중 속도 성능 에 대한 연구들은 주로 파랑 중 부가저항의 관점에서 수행되고 있다 (Hwang, et al., 2013; Park, et al., 2016). 파랑 중 선박 의 속도 성능과 관련하여 추진성능의 관점에서는 프로펠러로 유입되는 유속의 변화와 유동 현상에 대한 규명이 필요하나, 이 에 대한 연구는 제한적인 상황이다. 정수 중에서는 전통적으로 5공 피토관(five-hole pitot tube)을 선수 규칙파 중 만재상태의 KVLCC2 모형선 공칭반류 계측 김호 1 ․ 장진호 2,† ․ 황승현 1 ․ 김명수 1 ․ Yoshiki Hayashi 3 ․ Yasuyuki Toda 3 한국해양과학기술원 부설 선박해양플랜트연구소 1 삼성중공업(주) 중앙연구소 2 오사카대학교 지구종합공학 선박해양공학과 3 Nominal Wake Measurement for KVLCC2 Model Ship in Regular Head Waves at Fully Loaded Condition Ho Kim 1 ․ Jinho Jang 2,† ․ Seunghyun Hwang 1 ․ Myoung-Soo Kim 1 ․ Yoshiki Hayashi 3 ․ Yasuyuki Toda 3 Korea Research Institute of Ships and Ocean Engineering 1 Central Research Institute, Samsung Heavy Industries Co., Ltd. 2 Department of Naval Architecture and Ocean Engineering Osaka University, Japan 3 This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. In the ship design process, ship motion and propulsion performance in sea waves became very important issues. Especially, prediction of ship propulsion performance during real operation is an important challenge to ship owners for economic operation in terms of fuel consumption and route-time evaluation. Therefore, it should be considered in the early design stages of the ship. It is thought that the averaged value and fluctuation of effective inflow velocity to the propeller have a great effect on the propulsion performance in waves. However, even for the nominal velocity distribution, very few results have been presented due to some technical difficulties in experiments. In this study, flow measurements near the propeller plane using a stereo PIV system were performed. Phase-averaged flow fields on the propeller plane of a KVLCC2 model ship in waves were measured in the towing tank by using the stereo PIV system and a phase synchronizer with heave motion. The experiment was carried out at fully loaded condition with making surge, heave and pitch motions free at a forward speed corresponding to Fr=0.142 (Re=2.55×106) in various head waves and calm water condition. The phase averaged nominal velocity fields obtained from the measurements are discussed with respect to effects of wave orbital velocity and ship motion. The low velocity region is affected by pressure gradient and ship motion. Keywords : Nominal wake(공칭반류), Orbital velocity(궤도속도), Phase synchronizer(위상동기장치), Stereo PIV(스테레오 입자영상유 속계) pISSN:1225-1143, Vol. 53, No. 5, pp. 371-379, October 2016 eISSN:2287-7355, http://dx.doi.org/10.3744/SNAK.2016.53.5.371 대한조선학회논문집 Journal of the Society of Naval Architects of Korea Received : 27 July 2016  Revised : 5 August 2016  Accepted : 25 August 2016 † Corresponding author : Jinho Jang, jinho1.jang@samsung.com