Direct numerical simulation of vortex ring evolution from the laminar to the early turbulent regime
Archer, P.J., Thomas, T.G. and Coleman, G.N. (2008) Direct numerical simulation of vortex ring evolution from the laminar to the early turbulent regime. Journal of Fluid Mechanics, 598, 201-226. (doi:10.1017/S0022112007009883).
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Direct numerical simulation is used to study the temporal development of single vortex rings at various Reynolds numbers and core thicknesses. Qualitative differences between the evolution of thin- and thick-core rings are observed leading to a correction factor to the classical equation for the ring translational velocity. We compare the obtained linear modal growth rates with previous work, highlighting the role of the wake in triply periodic numerical simulations. The transition from a laminar to a turbulent ring is marked by the rearrangement of the outer core vorticity into a clearly defined secondary structure. The onset of the fully turbulent state is associated with shedding of the structure in a series of hairpin vortices. A Lagrangian particle analysis was performed to determine the ring entrainment and detrainment properties and to investigate the possibility of an axial flow being generated around the circumference of the core region prior to the onset of turbulence.
|Keywords:||vortex rings, direct numerical simulation|
|Subjects:||Q Science > QA Mathematics
T Technology > TL Motor vehicles. Aeronautics. Astronautics
Q Science > QC Physics
|Divisions:||University Structure - Pre August 2011 > School of Engineering Sciences > Aerodynamics & Flight Mechanics
|Date Deposited:||02 Jun 2008|
|Last Modified:||08 Jun 2012 12:21|
|Contact Email Address:||firstname.lastname@example.org|
|RDF:||RDF+N-Triples, RDF+N3, RDF+XML, Browse.|
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