• Title/Summary/Keyword: 공기부양선

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Numerical Analysis on Flow Fields and the Calculation of Wave Making Resistance about Air Supported Ships (수치시뮬레이션에 의한 공기부양선 주위의 유동장해석과 조파저항계산)

  • Na Y. I.;Lee Y.-G.
    • Journal of computational fluids engineering
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    • v.1 no.1
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    • pp.55-63
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    • 1996
  • Numerical computations are carried out to analyze the characteristics of flow fields around Air Supported Ships. The computations are performed in a rectangular grid system based on MAC(Marker And Cell) method. The governing equations are represented in finite difference forms by forward differencing in time and centered differencing in space except for its convection terms. For the certification of this numerical analysis method, the computations of flow fields around a Catamaran, an ACV(Air Cushion Vehicle) modeled with pressure distribution on free surface and two SES(Surface Effect Ship)'s are carried out, The results of the present computations are compared with the previously presented computational and experimental results in the same condition.

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A Study of Aero for Hovercraft (공기부양선의 추진기 고찰)

  • Kang, Dong-Woo;Lee, In-Sun
    • Special Issue of the Society of Naval Architects of Korea
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    • 2008.09a
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    • pp.62-67
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    • 2008
  • The hovercraft is the amphibious hovercraft. Design and manufacturing companies of the aero propeller exist rarely in the world. Hence the propeller has beef designed and manufactured by manufacturing companies which make aero propeller mainly. In this paper, the hovercraft propeller of similar, which is building and designing by HHIC, is considered the type of aero propeller, rotational speed, diameter, number of blades, Open air propeller efficiency. As the result of check, hovercraft which is necessary huge static thrust is needed the ducted propeller in order to improve climbing capacity. However, the number of blades and turning direction almost do not affect.

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Aerodynamic Characteristics of WIG Effect Vehicle with Direct Underside Pressurization (DUP (Direct Underside Pressurization)을 가진 위그선의 공력특성에 관한 연구)

  • Lee, Ju-Hee
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.7
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    • pp.655-663
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    • 2010
  • DUP (direct underside pressurization) is a device that can considerably increase lift, reduce take-off speed and minimize hump drag when a WIG effect vehicle takes off on the water surface. A 3-dimensional numerical investigation of a WIG effect vehicle with DUP is performed to analyze aerodynamic characteristics and the static height stability. The model vehicle, named Aircat, consists of a propeller in the middle of a fuselage, an air chamber under the fuselage, Lippisch-type wings and a large horizontal T-tail. The lift is mainly increased by the stagnation of the accelerated air coming into the air chamber through the channel in the middle of the fuselage. However, the accelerated air increases drag as well as reduces static height stability.

A Study on the Analysis of Lateral Vibration of Flexible Shafting System for Propulsion and Lift in Air Cushion Vehicle (공기부양선의 추진 및 부양축계 횡진동 해석에 관한 연구)

  • Son, Seon-Tae;Kil, Byung-Lea;Cho, Kwon-Hae;Kim, Jung-Ryul
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.2
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    • pp.241-249
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    • 2008
  • In this study, lateral vibration analysis has been conducted on a propulsion and lift shafting system for an air cushion vehicle using ANSYS code. The shafting system is totally flexible multi-elements system including air propeller, aluminum alloy of lift fan and thin walled shaft with flexible coupling. The analysis included the lateral natural frequencies, mode shapes and harmonic analysis of the shafting system taking into account three-dimensional models for propulsion and lifting shaft system. In case of ACV the yawing and pitching rate of craft will be quite high. During yawing and pitching of craft significant gyroscopic moment will be applied to the shafting and will generate high amplitude of lateral vibration. So, such a shafting system has very intricate lateral vibrating characteristics and natural frequencies of shafting must be avoided in the range of operating revolution. The control of lateral vibration is included in this study.

A Study on the Analysis of Axial Vibration of Flexible Shafting System for Propulsion and Lift in Air Cushion Vehicle (공기부양선의 추진 및 부양축계 종진동 해석에 관한 연구)

  • Son, Seon-Tae;Kil, Byung-Lea;Kim, Jung-Ryul
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.6
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    • pp.768-776
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    • 2007
  • In this study, axial vibration analysis has been conducted on a propulsion and lift shafting system for an air cushion vehicle using ANSYS code. The shafting system is totally flexible multi-elements system including wood composite material of air propeller. aluminum alloy of lift fan and thin walled shaft with flexible coupling. The analysis calculated the axial natural frequencies and mode shapes of the shafting system taking into account an equivalent mass-elastic model for shafting system as well as the three-dimensional models for propeller blade and fan impeller. Such a flexible shafting system has very intricate vibrating characteristics and especially, axial natural frequencies of flexible components such as propeller blade and impeller of lift fan can be lower to the extent that causes a resonance in the range of operating revolution. The results for axial vibration analysis are presented and compared with the results of axial vibration test for lift fan conducted during Sea Trial.

A Study on the Analysis of Torsional Vibration of Branched Shafting System for Propulsion and Lift in Air Cushion Vehicle (공기부양선의 추진 및 부양축계 비틀림진동 해석 연구)

  • Son, Seon-Tae;Kim, Jung-Ryul
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.4
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    • pp.335-342
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    • 2007
  • A propulsion and lift shafting system in an air cushion vehicle is flexible multi-elements system which consists of two aeroderivative gas turbines with own bevel gears, four stage lift fan reduction gear, two stage propulsion reduction gear air propellers and high capacity of lifting fans. In addition, the system includes the multi-branched shafting with multi-gas turbine engines and thin walled shaft with flexible coupling. Such a branched shafting system has very intricate vibrating characteristics and especially, the thin walled shaft with flexible couplings can lower the torsional natural frequencies of shafting system to the extent that causes a resonance in the range of operating revolution. In this study, to evaluate vibrational characteristics some analytical methods for the propulsion and lift shafting system are studied. The analysis, including natural frequencies and mode shapes, for five operation cases of the system is conducted using ANSYS code with a equivalent mass-elastic model.