Title page for etd-0719115-132401


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URN etd-0719115-132401
Author Ping-Ben Liu
Author's Email Address No Public.
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Department Mechanical and Electro-Mechanical Engineering
Year 2014
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Numerical Investigation for Two- and Three-Dimensional Turbulent Cavitating Flows
Date of Defense 2015-07-29
Page Count 56
Keyword
  • filter
  • side-entrant jet
  • generality
  • re-entrant jet
  • cavitation
  • Abstract Cavitation models and turbulent models are widely used to predict cavitation phenomenon in numerical simulations. The coefficients which dominate the evaporation and condensation rates in cavitation models are often empirical and tunable. To reduce the sensitivity and raise the generality of the coefficients, unsteady cloud cavitation cases on 2D Clark Y and NACA66 hydrofoils were simulated with different combinations of empirical coefficients and turbulent treatments. The Reynolds-Averaged Navier-Stokes (RANS) and Partially Averaged Navier-Stokes (PANS) turbulent approach was coupled with a homogeneous cavitation model to calculate the time-averaged lift coefficient, time-averaged drag coefficient and frequency of cavitation shedding behavior. The suitable empirical coefficients are presented in this study.
      An unsteady 3D simulation on a Delft twist 11 hydrofoil was also performed. The re-entrant jets and structure of the cavitating flow around the hydrofoil was investigated. The results on time-averaged lift coefficient, three dimensional cavity structure and shedding frequency agreed well with experimental observation. Analysis of the flow field reveals that secondary shedding is an omen of primary shedding and induced by a pair of side-entrant jets. These side-entrant jets promote re-entrant jets to move further upstream. Eventually, the attached cavity is cut off by the re-entrant jets, leading to the primary shedding.
    Advisory Committee
  • Kuang-Chuan Lin - chair
  • Yang-Yao Niu - co-chair
  • Hsin-Fu Huang - co-chair
  • Chien-Chou Tseng - advisor
  • Files
  • etd-0719115-132401.pdf
  • Indicate in-campus at 2 year and off-campus access at 2 year.
    Date of Submission 2015-08-19

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