Bifurcations of Atmospheric Vortices

Gabuardi Diaz, Jesse (2011). Bifurcations of Atmospheric Vortices B.Sc Thesis, School of Engineering, The University of Queensland.

       
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Author Gabuardi Diaz, Jesse
Thesis Title Bifurcations of Atmospheric Vortices
School, Centre or Institute School of Engineering
Institution The University of Queensland
Publication date 2011
Thesis type B.Sc Thesis
Supervisor Alexander Klimenko
Total pages 53
Language eng
Subjects 0913 Mechanical Engineering
0901 Aerospace Engineering
Formatted abstract
Hurricanes/Cyclones and Tornados are both regarded as atmospheric vortices, however there exists no current research on the comparison between theory and flow structure of
such phenomena. Is it possible that research that has been achieved in one field may be used to further advance research in another? This thesis investigates the theory of
Hurricanes and Tornadoes and determines the similarities between such theories. This thesis also aims to detail the dynamics and bifurcations of vortices in general and theorise the flow structure, in particular the formation of the “eye” within Tornadoes, based upon vortex breakdown.

By reviewing vortex breakdown theory, it is believed that the formation of several breakdowns occurring in the core of a Tornado could cause a formation of an “eye” where little or no flow might occur. These breakdowns occur at some distance below the top boundary layer; however for increases in the swirl ratio the stagnation point, the point where the breakdown formation occurs, moves closer to the top boundary surface. The breakdown consists of a bubble like structure, flow is forced to reverse down the axis of the vortex and recirculate behind the stagnation point. It was found that the swirl ratio is the most dominate parameter that governs the structure of Tornado like vortices.

From comparisons of the flow structures in Cyclones/ Hurricanes and Tornadoes they appear to be similar. However unlike Tornadoes where the flow structure is primarily described by the Reynolds number and the swirl ratio, Cyclones are primarily influenced by the coriolis parameter and other conditions around them. Essentially Cyclones are driven by large
amounts of latent heat of condensation thus a Cyclone visualised as a giant vertical heat engine.

Thus similarities between Cyclones/Hurricane and Tornadoes are small, hence using theoretical information describing the flow within a Cyclone provides little or no benefits in
the area of Tornadoes, and vice versa.
Keyword bifurcation
Atmospheric vortices

Document type: Thesis
Collection: UQ Theses (non-RHD) - UQ staff and students only
 
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Created: Tue, 02 Dec 2014, 13:55:21 EST by Ahmed Taha Siddiqui on behalf of Scholarly Communication and Digitisation Service