A Marked Change in Subcavitating-Cascade-Performance Resulted from a Very Small Modification in Leading Edges

Hitoshi Soyama, Tsutomu Narasaka, Risaburo Oba, Ryoichiro Oshima, Johshiro Sato, Seiichi Tanabe, Katsumasa Shimmei

Research output: Contribution to journalArticle

Abstract

For the first step to find low-drag thin hydrofoils in cascade applicable to Kaplan-turbines, the subcavitating performance and the corresponding cavitation aspects for two different hydrofoils whose shapes are quite the same except the neighborhood of the leading edge within one percent chord. The leading edges are somewhat modified, for two cascade arrangements of a pitch-chord-ratio t/l = 1.14 and of two cascade angles θ = 23° and 35°, for various cavitation numbers and various incidences. Clearly, a marked change in drag is resulted from such a very small modification around the edge, which is closely related to the boundary layer separation around the leading edge. It is also suggested to the suitable modifications without separation bubble.

Original languageEnglish
Pages (from-to)1283-1288
Number of pages6
JournalTransactions of the Japan Society of Mechanical Engineers Series B
Volume58
Issue number548
DOIs
Publication statusPublished - 1992 Jan 1
Externally publishedYes

Keywords

  • Blade
  • Bubble
  • Cascade
  • Cavitation
  • Separation
  • Water Turbine

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering

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