Title page for etd-0730113-051304


[Back to Results | New Search]

URN etd-0730113-051304
Author Jin-Tung Lu
Author's Email Address No Public.
Statistics This thesis had been viewed 5385 times. Download 833 times.
Department Mechanical and Electro-Mechanical Engineering
Year 2012
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Investigation of cavitating flow by lagrangian coherent structure
Date of Defense 2013-07-23
Page Count 100
Keyword
  • Cavitation
  • FTLE
  • Turbulence
  • Particle tracking
  • LCS
  • Abstract Turbulent cavitating flows are ubiquitous in our daily life and technologies, which will induce the noises, material removal, and efficiency reduction of the flow machinery. As the result, it is important to investigate the flow structures of the cavitating flow to predict its dynamical behaviors effectively. In the present study, we utilize the volume of fraction techniques to time-dependent turbulent cavitating flows.
    Lagrangian Coherent Structures (LCS) have been developed to highlight the flow structures recently. It is a trajectory-basedapproach from a Lagrangian perspective by considering the fluid as a dynamical system of fluid particles rather than a continuum. This method is frame-independent and more useful to capture the dynamical features of the flows, which can be missed in the traditional Eulerian analyses based on the velocity or vorticity fields.
    This dissertation utilizes the finite-time Lyapunov exponent(FTLE) and LCS to get a better understanding of the flow dynamics and underlying physics of the simulated cavitating flows for different representative phenomena during the corresponding stages. It is found that LCS can capture the re-entraint jet front and also indicate that fluid around lower surface could be attracted to the upper surface of the hydrofoil when the induced cavity grows around the trailing edge. This dissertation also analyzes the complicated flow interaction around the trailing edge when the multiple circulation and cavitation regions are formed by particle tracking method.
    Advisory Committee
  • Kuang-Chuan Lin - chair
  • Fu-Ling Yang - co-chair
  • Yang-Yao Niu - co-chair
  • Chien-Chou Tseng - advisor
  • Files
  • etd-0730113-051304.pdf
  • indicate access worldwide
    Date of Submission 2013-09-03

    [Back to Results | New Search]


    Browse | Search All Available ETDs

    If you have more questions or technical problems, please contact eThesys