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Instabilities of interacting vortex rings generated by an oscillating disk
(American Physical SocietyPhysical Review E, 2016-09-14)
We propose a natural model to probe in a controlled fashion the instability of interacting vortex rings shed from the edge of an oblate spheroid disk of major diameter $\textit{c}$, undergoing oscillations of frequency ...
Non-axisymmetric instabilities in discs with imposed zonal flows
(Oxford University PressMonthly Notices of the Royal Astronomical Society, 2016-09-06)
We conduct a linear stability calculation of an ideal Keplerian flow on which a sinusoidal zonal flow is imposed. The analysis uses the shearing sheet model and is carried out both in isothermal and adiabatic conditions, ...
Dynamical and radiative processes in the Upper Troposphere/Lower Stratosphere
(Department of Applied Mathematics and Theoretical Physics, University of CambridgeUniversity of CambridgeDepartment of Applied Mathematics and Theoretical PhysicsCorpus Christi College, 2016-06-28)
The overall aim of this thesis is to gain a better understanding of certain key attributes and processes in the Upper Troposphere/Lower Stratosphere (UTLS). This work involves exploring the interactions between radiation ...
Size segregation in a granular bore
(American Physical SocietyPhysical Review Fluids, 2016-10-06)
We investigate the effect of particle-size segregation in an upslope propagating granular bore. A bidisperse mixture of particles, initially normally graded, flows down an inclined chute and impacts with a closed end. This ...
Arbitrary axisymmetric steady streaming: Flow, force and propulsion
(SpringerJournal of Engineering Mathematics, 2016)
A well-developed method to induce mixing on microscopic scales is to exploit flows generated by steady streaming. Steady streaming is a classical fluid dynamics phenomenon whereby a time-periodic forcing in the bulk or ...
Particle-Vortex Duality from 3D Bosonization
(American Physical SocietyPhysical Review X, 2016-09-19)
We show how particle-vortex duality in $d$ = 2 + 1 dimensions arises as part of an intricate web of relationships between different field theories. The starting point is “bosonization,” a conjectured duality that uses flux ...
Multiple instability of layered stratifed plane Couette flow
(Cambridge University PressJournal of Fluid Mechanics, 2017-02-25)
We present the linear stability properties and nonlinear evolution of two-dimensional plane Couette flow for a statically stable Boussinesq three-layer fluid of total depth 2$h$ between two horizontal plates driven at ...
Viscous effects on the acoustics and stability of a shear layer over an impedance wall
(Cambridge University PressJournal of Fluid Mechanics, 2017-01-01)
The effect of viscosity and thermal conduction on the acoustics in a shear layer above an impedance wall is investigated numerically and asymptotically by solving the linearised compressible Navier–Stokes equations (LNSE). ...
Aerotaxis in the closest relatives of animals
(eLife Sciences Publications LtdeLife, 2016-11-24)
As the closest unicellular relatives of animals, choanoflagellates serve as useful model organisms for understanding the evolution of animal multicellularity. An important factor in animal evolution was the increasing ocean ...
Bio-inspired canopies for the reduction of roughness noise
(ElsevierJournal of Sound and Vibration, 2016-12-22)
This work takes inspiration from the structure of the down covering the flight feathers of larger species of owls, which contributes to their ability to fly almost silently at frequencies above 1.6 kHz. Microscope photographs ...