dc.contributor.advisor |
Stow, Dave |
en |
dc.contributor.author |
Bradley, Stuart G. |
en |
dc.date.accessioned |
2007-08-11T09:33:37Z |
en |
dc.date.available |
2007-08-11T09:33:37Z |
en |
dc.date.issued |
1975 |
en |
dc.identifier |
THESIS 75-260 |
en |
dc.identifier.citation |
Thesis (PhD)--University of Auckland, 1975 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/1397 |
en |
dc.description |
Full text is available to authenticated members of The University of Auckland only. |
en |
dc.description.abstract |
An experimental study is described of highly reproducible collisions between charged or uncharged drops of different radius moving at correct relative terminal velocities. Experimental data describes rate of drop rotation, axial length, coalescence efficiency, and number and size of large and small products. All measured quantities are expressed as functions of both impact parameter and drop charge.
Theories describe drainage of a deformable and of an electro-statically unstable airfilm trapped between colliding drop Surfaces. Coalescence is predicted in accordance with observations. An analytic stability analysis method is tested against known results for a drop oscillating in an intense electric field. When applied to the collision problem, in conjunction with a model of asymmetric drop breakup, upper and lower limits of impact parameter are predicted for drop stability, in agreement with experiment.
Results of experiment and theory are parameterized so that they may be readily used in any drop spectrum modification calculation. As an example, the modification of drop spectrum between cloud base and ground is examined. Properties and parameterization of initial drop spectra are thoroughly investigated. It is found that satellite droplet production dominates drop spectra so that results are insensitive to initial assumed spectrum shapes. A numerical investigation of time-dependent modifications indicates that satellite drop production allows drop spectra to follow rapid changes since numbers of small drops are associated with the presence of drops with high terminal velocity.
Fits of the theory to experimental drop distributions obtained at the ground show excellent agreement. Correspondence between fine structure in experimental and theoretical distributions is demonstrated. Time cross-correlations between different parts of an experimental drop spectrum show that numbers of small drops are associated in time and space with numbers of medium-radius drops. Cross-correlation between very large and very small drops shows a time delay consistent with fall from an active region of the cloud.
Drop charging mechanisms are discussed. Theory is developed describing charge exchange when drops are separated by a finite liquid filament. Satellite drop charges are calculated. Theoretical models of joint drop size and drop charge show qualitative agreement with joint spectra measured at the ground. |
en |
dc.language.iso |
en |
en |
dc.publisher |
ResearchSpace@Auckland |
en |
dc.relation.ispartof |
PhD Thesis - University of Auckland |
en |
dc.relation.isreferencedby |
UoA9921767914002091 |
en |
dc.rights |
Restricted Item. Available to authenticated members of The University of Auckland |
en |
dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated |
en |
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
en |
dc.title |
Physical and electrical properties of raindrop interactions |
en |
dc.type |
Thesis |
en |
thesis.degree.grantor |
The University of Auckland |
en |
thesis.degree.level |
Doctoral |
en |
thesis.degree.name |
PhD |
en |
dc.rights.holder |
Copyright: The author |
en |
dc.identifier.wikidata |
Q112837490 |
|