{"id":{"repo_id":"auckland-ms","oai_identifier":"oai:researchspace.auckland.ac.nz:2292/64090"},"canonical_url":"https://search.dev.ndltd.org/etd/auckland-ms/oai:researchspace.auckland.ac.nz:2292/64090","repository":{"repo_id":"auckland-ms","name":"University of Auckland","base_url":"https://researchspace.auckland.ac.nz/server/oai/request"},"display":{"title":"Engineering the Whirlwind","abstract":"An analysis of atmospheric buoyancy vortices is made, suggesting they can be usefully analysed as heat engines, converting Convectively Available Potential Energy (CAPE) contained in a rising columnar core, into rotational kinetic energy. The cold reservoir of the heat engine is considered as being located at the point where the coherent vortex core breaks down into a turbulent plume. Vortex coherence at small diameters is found to depend on the suppression of turbulent mixing, arising from hydrodynamic stability and stable radial stratification of density in the vortex core, combined with sufficient lapse-rate divergence. Lapse-rate divergence describes a situation where the vortex core cools more slowly in rising than the surrounding atmosphere does. The height and temperature of the cold-reservoir of the heat-engine driving the vortex, are modelled as resulting from this behaviour. Experiments are reported that measure this suppression of turbulent mixing in laboratory vortices and compare it to predictions, based on published models based on non-dimensional numbers. Estimates of the behaviour of saturated vortices rising in open atmosphere are made, based on those measurements of the suppression of turbulent mixing, to estimate design parameters for a field demonstrator of the concept of a vortex station, which is envisaged as an installation capable of generating a tall artificial buoyancy vortex with high wind-speeds occurring at the ground.","abstract_html":"An analysis of atmospheric buoyancy vortices is made, suggesting they can be usefully analysed as heat engines, converting Convectively Available Potential Energy (CAPE) contained in a rising columnar core, into rotational kinetic energy. The cold reservoir of the heat engine is considered as being located at the point where the coherent vortex core breaks down into a turbulent plume. Vortex coherence at small diameters is found to depend on the suppression of turbulent mixing, arising from hydrodynamic stability and stable radial stratification of density in the vortex core, combined with sufficient lapse-rate divergence. Lapse-rate divergence describes a situation where the vortex core cools more slowly in rising than the surrounding atmosphere does. The height and temperature of the cold-reservoir of the heat-engine driving the vortex, are modelled as resulting from this behaviour. Experiments are reported that measure this suppression of turbulent mixing in laboratory vortices and compare it to predictions, based on published models based on non-dimensional numbers. Estimates of the behaviour of saturated vortices rising in open atmosphere are made, based on those measurements of the suppression of turbulent mixing, to estimate design parameters for a field demonstrator of the concept of a vortex station, which is envisaged as an installation capable of generating a tall artificial buoyancy vortex with high wind-speeds occurring at the ground.","abstract_has_math":false,"creators":["Hawkes, Neil Andrew"],"institution":"ResearchSpace@Auckland","degree_name":"PhD","degree_level":"Doctoral","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":[],"advisors":["Flay, Richard","Cater, John"],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022","date_published":"2022","updated_at":"2026-07-24T01:05:11Z","subjects":[],"languages":[],"rights":["Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated."],"rights_urls":["https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm"],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2292/64090","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Flay, Richard","Cater, John"]},{"key":"dc:creator","label":"Author","values":["Hawkes, Neil Andrew"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2023-05-22T01:48:24Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2023-05-22T01:48:24Z"]},{"key":"dc:date.issued","label":"Date","values":["2022"]},{"key":"dc:publisher","label":"Institution","values":["ResearchSpace@Auckland"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["UoA"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["PhD"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["The University of Auckland"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated."]},{"key":"dc:rights.uri","label":"Rights URI","values":["https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/2292/64090"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["An analysis of atmospheric buoyancy vortices is made, suggesting they can be usefully analysed as heat engines, converting Convectively Available Potential Energy (CAPE) contained in a rising columnar core, into rotational kinetic energy. The cold reservoir of the heat engine is considered as being located at the point where the coherent vortex core breaks down into a turbulent plume. Vortex coherence at small diameters is found to depend on the suppression of turbulent mixing, arising from hydrodynamic stability and stable radial stratification of density in the vortex core, combined with sufficient lapse-rate divergence. Lapse-rate divergence describes a situation where the vortex core cools more slowly in rising than the surrounding atmosphere does. The height and temperature of the cold-reservoir of the heat-engine driving the vortex, are modelled as resulting from this behaviour. Experiments are reported that measure this suppression of turbulent mixing in laboratory vortices and compare it to predictions, based on published models based on non-dimensional numbers. Estimates of the behaviour of saturated vortices rising in open atmosphere are made, based on those measurements of the suppression of turbulent mixing, to estimate design parameters for a field demonstrator of the concept of a vortex station, which is envisaged as an installation capable of generating a tall artificial buoyancy vortex with high wind-speeds occurring at the ground."]},{"key":"dc:title","label":"Title","values":["Engineering the Whirlwind"]}]}],"canonical_facts":{"dc:contributor.advisor":["Flay, Richard","Cater, John"],"dc:creator":["Hawkes, Neil Andrew"],"dc:date.accessioned":["2023-05-22T01:48:24Z"],"dc:date.available":["2023-05-22T01:48:24Z"],"dc:date.issued":["2022"],"dc:description.abstract":["An analysis of atmospheric buoyancy vortices is made, suggesting they can be usefully analysed as heat engines, converting Convectively Available Potential Energy (CAPE) contained in a rising columnar core, into rotational kinetic energy. The cold reservoir of the heat engine is considered as being located at the point where the coherent vortex core breaks down into a turbulent plume. Vortex coherence at small diameters is found to depend on the suppression of turbulent mixing, arising from hydrodynamic stability and stable radial stratification of density in the vortex core, combined with sufficient lapse-rate divergence. Lapse-rate divergence describes a situation where the vortex core cools more slowly in rising than the surrounding atmosphere does. The height and temperature of the cold-reservoir of the heat-engine driving the vortex, are modelled as resulting from this behaviour. Experiments are reported that measure this suppression of turbulent mixing in laboratory vortices and compare it to predictions, based on published models based on non-dimensional numbers. Estimates of the behaviour of saturated vortices rising in open atmosphere are made, based on those measurements of the suppression of turbulent mixing, to estimate design parameters for a field demonstrator of the concept of a vortex station, which is envisaged as an installation capable of generating a tall artificial buoyancy vortex with high wind-speeds occurring at the ground."],"dc:identifier.uri":["https://hdl.handle.net/2292/64090"],"dc:publisher":["ResearchSpace@Auckland"],"dc:relation.isreferencedby":["UoA"],"dc:rights":["Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated."],"dc:rights.uri":["https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm"],"dc:title":["Engineering the Whirlwind"],"dc:type":["Thesis"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["Doctoral"],"thesis:degree_name":["PhD"],"thesis:institution_name":["The University of Auckland"]},"updated_at":"2026-07-24T01:05:11Z"}