Experimental investigations of granular matter flow regimes leading to insight into lahar flow dynamics : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Earth Science at Massey University, Manawatū, New Zealand

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dc.contributor.authorNeather, Adam Charles
dc.date.accessioned2017-11-29T23:46:48Z
dc.date.available2017-11-29T23:46:48Z
dc.date.issued2016
dc.description.abstractThe flow of granular material governs numerous natural processes including the aeolian dynamics of sand dune formation, sub-aerial and submarine mass flows, the collective dynamics of ice blocks floating on the ocean, avalanches of debris and snow, as well as volcanic granular-fluid flow processes, such as pyroclastic density currents, volcanogenic debris flows and lahars. Lahars are a particularly important type of granular flow, in regards to its possible effect on human life; they are debris and water-based flows, initiated by volcanic processes. A fascinating aspect about granular matter is the co-existence of behaviour similar to two or all three of the classical states of matter (solid, liquid, gas) and their frequent transitions between these behaviours. Despite the ubiquity of these transitions in nature and industry, the fundamental physics of granular matter remains a mystery, to the extent that a unified theory to describe the motion and behaviour of granular matter is still absent. This study is an attempt to simulate lahars and their erosion/deposition mechanics in the laboratory by making use of a rotating drum. A rotating drum can be treated as an analogue for a lahar because it allows for erosion and deposition to occur as an active region of material flows over a passive, erodible bed. In nature these processes are transitory and highly dynamic, but an experimental analogue allows for the processes to be observed in a steady system. Results include detailed maps of the various regions in a flowing granularmaterial correlated to the speed of rotation of the flows. The changing status of the active and passive regions allows for measurements of the erosion mechanics within the drum. Also, potentially identified are two new phenomena; high speed rotations appear to include features similar to Kelvin-Helmholtz instabilities, and enclosed regions of subrotation, which are referred to as self-enclosed circulation cells (SECCs).en_US
dc.identifier.urihttp://hdl.handle.net/10179/12463
dc.language.isoenen_US
dc.publisherMassey Universityen_US
dc.rightsThe Authoren_US
dc.subjectGranular flowen_US
dc.subjectLaharsen_US
dc.subjectMathematical modelsen_US
dc.subjectResearch Subject Categories::NATURAL SCIENCES::Earth sciencesen_US
dc.titleExperimental investigations of granular matter flow regimes leading to insight into lahar flow dynamics : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Earth Science at Massey University, Manawatū, New Zealanden_US
dc.typeThesisen_US
massey.contributor.authorNeather, Adam
thesis.degree.disciplineEarth Scienceen_US
thesis.degree.grantorMassey Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophy (PhD)en_US
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