Waves and oscillation in vortex rings

Pao Yue-kong Library Electronic Theses Database

Waves and oscillation in vortex rings

 

Author: Huang, Jun
Title: Waves and oscillation in vortex rings
Degree: M.Phil.
Year: 2005
Subject: Hong Kong Polytechnic University -- Dissertations
Vortex-motion -- Mathematical models
Fluid dynamics
Oscillations
Waves
Department: Dept. of Mechanical Engineering
Pages: xv, 119 leaves : ill. (some col.) ; 30 cm
Language: English
InnoPac Record: http://library.polyu.edu.hk/record=b1818124
URI: http://theses.lib.polyu.edu.hk/handle/200/2085
Abstract: The problem of vortex ring oscillation and waves in vortex tube can be traced back to 19th century (Lord Kelvin, 1867 and 1880). This thesis concerns some investigation on the oscillation and wave phenomenon in vortex rings. After a brief historical review of the investigation in vortex dynamics and an introduction of the experimental apparatus and optical metrology, a series of experimental observations are presented a dual-wavelike instability in vortex rings. The first wavelike instability is presented at Reynolds number range between 600 and 1000 for circular vortex ring and the second one could be observed in axisymmetric vortex rings (azimuthal number n >= 2) at laminar phase and transition phases of the first instability. The azimuthal number of the first instability depends on the ratio n (core radius to ring radius), while the mode of the second one accords with the shape of the orifice. Some other characters of the wave-like instability were also investigated by experiments, such as special wavelength and oscillation period. The experimental results are compared with some theoretical prediction. Because both this dual-wave spectrum in vortex rings and the superposed wave in vortex column are similar to those in cylindrical solid beams, following the existing beam theory, a four-helical-wave model is set up.

Files in this item

Files Size Format
b18181247.pdf 3.641Mb PDF
Copyright Undertaking
As a bona fide Library user, I declare that:
  1. I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
  2. I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
  3. I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.

     

Quick Search

Browse

More Information