岬先端で剥離する渦の吸い込み速度 : 理論値と実験値の比較 Suck-up Velocity of an Eddy Separated at the Tip of a Headland : A comparison of theoretical and experimental data

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Abstract

岬先端で剥離する渦の発生周期と渦の吸い込み現象について検討した。剥離渦は自らスピンダウンしながら余剰エネルギーを生じ,その余剰エネルギーは底層水の吸い上げに消費される。剥離後の渦は非粘性のRankinn Combined Vortexとし,剥離時の岬の前面に発達する境界層厚さを1/7乗速度分布則およびプラントルの混合距離理論を用いて定式化し,吸い込み速度,発生周期について実験と比較して理論の有効性を確認した。

A theory related to the suck-up phenomenon and the generation period of eddy separated at the tip of aheadland has been developed. When the boundary layer develops in front of a headland wall and flow separationoccurs at the tip of the headland, eddies are generated and flow down accompanying spin down and suck-up phenomena. By using the l/7-th-power velocity distribution law and Prandtle's mixing-length theory, it is derivedtheoretically that the boundary layer thickness which develops along the headland wall is proportional to the headlandlength. After the eddy separation, the eddy is treated with the Rankine Combined Vortex. An excesskinetic energy appears virtually in the separated eddy itself owing to the spin down of eddy and the excess energyis consumed in sucking up the bottom waters. The suck-up Velocity is deduced as W= Γ/(2πa), Where Γ is the circulation and 'a' is the radius of separated eddy.

Journal

  • Journal of Fisheries Engineering

    Journal of Fisheries Engineering 32(2), 119-126, 1995-11-30

    The Japanese Society of Fisheries Engineering

References:  7

Cited by:  1

Codes

  • NII Article ID (NAID)
    10008438649
  • NII NACSIS-CAT ID (NCID)
    AN10278554
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    09167617
  • Data Source
    CJP  CJPref  J-STAGE  JASI 
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