• Title/Summary/Keyword: Lagrangean methods

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Superconservative Finite Difference Scheme for Gas Dynamics

  • KOVALENKO ILYA G.
    • Journal of The Korean Astronomical Society
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    • v.34 no.4
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    • pp.271-273
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    • 2001
  • We present a 4-parameter implicit Lagrangean code which satisfies conservation of mass, linear and angular momenta, energy and entropy simultaneously. The primary advantage of this scheme is possibility to control dissipative properties of the scheme avoiding the effects of numerical viscosity.

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Report of East Sea Crossing by Underwater Glider (수중 글라이더를 이용한 동해 횡단 사례 보고)

  • Park, Yo-Sup;Lee, Shin-Je;Lee, Yong-Kuk;Jung, Seom-Kyu;Jang, Nam-Do;Lee, Ha-Woong
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.17 no.2
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    • pp.130-137
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    • 2012
  • The underwater glider using conception of Lagrangian method, is a new observation platform to understand the properties of the ocean vertically. In 2011 March, KORDI made a first successful autonomous trip from Hupo to west coast of Uleungdo piloting Littoral Glider of Alaska Native Technology LLC. The journey considered many environmental variables and route vigilantly selected, the glider covered 177 km horizontally and took approximately 6 days (153 hours). Despite the existence of 1 kt eddy current, Sound velocity sampling was conducted from 5 meters and reaching maximum of 200 meters depth at each dive. It successfully collected sound velocity and temperature profile at every 5 seconds totaling up to 1408 profiles using SVT&P sensor. During the flight it was also a mission to check the diverse modes of the glider i.e. spiral, waypoints, heading, drift and hover could function without a defect in a given situation. These modes were thoroughly monitored and it could be considered that the glider handled it well during the flight. As a result of this test flight, it was evident that the given underwater glider could operate under 2kt current environment with users defined heading and depth, also with the payload up to 5 kg without changing internal buoyancy.