• Title/Summary/Keyword: Round bilge

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A Study on the Hull Form Design of Semi-Planing Round-Bilge Craft (Round-Bilge 고속 반활주선의 선형특성 및 설계에 관한 연구)

  • Lee, Jung-Gwan;Jung, Kwang-Hyo;Suh, Sung-Bu;Chun, Ho-Hwan;Lee, In-Won
    • Journal of Ocean Engineering and Technology
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    • v.24 no.4
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    • pp.59-65
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    • 2010
  • This study presents the design procedure for optimizing the semi-planing hull form, including appendages, using numerical and experimental methods. Four different referenced semi-planing hull forms were compared to determine their hydrodynamic performances, and one of the hull forms was modified for optimum operation at high-speed conditions (0.4 < $F_{NL}$ < 0.9). The optimized, semi-planing hull form was tested in the towing tank to investigate its resistance characteristics. Also, the results of the model tests with differing design parameters were used to choose the stern wedge and the spray strip to improve the hydrodynamic performance at high speeds.

Effect of Stern Wedge on the Wave Making Resistance of Chine Hull Form (선미 웨지가 차인선형의 조파저항에 미치는 영향)

  • Lee Dae-Hoon;Lew Jae-Moon;Kang Dae-Sun
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.9 no.2
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    • pp.92-97
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    • 2006
  • Hull forms of a high speed small boat have been developed through numerical studies. A round bilge type hull form has been drived form a using chine hull form with HCAD, a hull form variation software. Wave resistance and the flow fields around the ships have been computed using well-known software, WAVIS. This software employs Rankine source method with non-linear tree surface condition as well as dry transom boundary conditions. The round bilge hull form showed better resistance performance than to the chine hull form for the whole speed range. However, considering the building and labor costs of the small shipyard, the chine hull form has been selected and its wave resistance characteristics has been improved by modifying the bow regions and applying the stem wedge. It is found that the effect of stem wedge is quite satisfactory to improve the resistance characteristics of high speed chine hull form.

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차인형 어선의 저항성능에 미치는 선미 웨지의 영향

  • 유재문;이대훈;강대선
    • Journal of Korea Ship Safrty Technology Authority
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    • v.18
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    • pp.26-38
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    • 2005
  • 본 논문에서는 KRISO에서 개발한 선형설계 전용 프로그램인 HCAD와 조파저항 계산 프로그램인 WAVIS를 사용하여 소형 어선을 개발한 예를 보이고 있다. 소형 고속 어선으로 사용되고 있는 차인형 선형을 기준선으로 하여 둥근바닥 선형(Round Bilge Hull Form)을 설계한 과정과, 두 가지 선형에 대한 저항 특성을 이용하여 선체 주위의 유동장과 조파저항을 계산 하였다. 차인형 선형의 저항 특성이 둥근 바닥 선형에 비해 다소 크게 나타났으나 소형 조선소의 건조비를 감안하여 차인형 선형에 대한 저항 감소를 시도하였다. 차인형 선형은 최근 어선의 고속화에 따라 고속 운항시 과도한 선수파가 발생하기 쉽고, 심한 트림이 발생할 가능성이 있으므로, 이러한 문제를 해결하기 위해 선미웨지를 설계하였으며, WAVIS를 이용한 수치계산에 의해 저항 성능이 개선되었음을 확인하였다.

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Model tests on resistance and seakeeping performance of wave-piercing high-speed vessel with spray rails

  • Seo, Jeonghwa;Choi, Hak-Kyu;Jeong, Uh-Cheul;Lee, Dong Kun;Rhee, Shin Hyung;Jung, Chul-Min;Yoo, Jaehoon
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.8 no.5
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    • pp.442-455
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    • 2016
  • The resistance and seakeeping performance of a high-speed monohull vessel were investigated through a series of model tests in a towing tank. The hull had a slender wave-piercing bow, round bilge, and small deadrise angle on stern. Tests on the bare hull in calm water were first conducted and tests on spray rails followed. The spray rails were designed to control the flow direction and induce a hydrodynamic lift force on the hull bottom to reduce trim angle and increase rise of the hull. The maximum trim of the bare hull was $4.65^{\circ}$ at the designed speed, but the spray rails at optimum location reduced trim by $0.97^{\circ}$. The ship motion in head seas was examined after the calm water tests. Attaching the rails on the optimum location effectively reduced the pitch and heave motion responses. The vertical acceleration at the fore perpendicular reduced by 11.3%. The effective power in full scale was extrapolated from the model test results and it was revealed that the spray rails did not have any negative effects on the resistance performance of the hull, while they effectively stabilized the vessel in calm water and waves.