Student Number : 9910049F -
MSc (Eng) dissertation -
School of Mechanical, Industrial and Aeronautical Engineering -
Faculty of Engineering and the Built Environment / Cavitation was generated in tap water samples by the transmission of tension waves into
the liquid, using a hydrodynamic shock tube. The liquid cavitated at absolute negative
pressures of about -1 bar. Simulations of bubble responses showed qualitative agreement
with experimental observations of oscillatory growth and collapse cycles. Pressure
records showed secondary pressure pulsations, confirming the oscillatory nature of the
collapse at each rise in pressure. More quantitative comparison of theory and
photographic records would require a camera with a higher capture rate. Experiments
using another experimental facility involved liquid compression waves with peak static
pressures of up to about 1 MPa, which were transmitted from a conventional gas shock
tube into a liquid section and were intended to be reflected at the free surface as
expansion waves. These experiments were unsuccessful in producing absolute negative
pressures or cavitation that was visible through an optical observation section. This was
attributed to transition layer effects and pulse attenuation, which contributed to lowering
of the peak negative pressure behind the expansion wave, as well as the depth of the
transducer and observation section below the free surface, which may have been too low
for the peak tension to be superimposed on the lower pressure behind the incident
compression wave. Pressure records suggested that, for lower driver pressures, cavitation
occurred below the observation section, although this could not be verified optically.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/1665 |
| Date | 14 November 2006 |
| Creators | Sam, Justin Shang |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 7957648 bytes, application/pdf, application/pdf |
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