Direct numerical simulation of turbulent intermediate Froude number fountain flow

Williamson, N., Armfield, S.W., and Lin, W. (2008) Direct numerical simulation of turbulent intermediate Froude number fountain flow. ANZIAM Journal, 50. pp. 16-30.

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Abstract

Fountains are an important flow in many industrial and geophysical problems but the understanding of this flow at low Froude numbers is limited. In this study we use direct numerical simulation to examine two regimes of turbulent fountain flow, weak flow at Fr = 2:2 and very weak flow at Fr = 0:45. At Fr = 0:45 buoyancy stabilises the flow and there is little entrainment of ambient fluid. Kelvin-Helmholtz instabilities are generated at the interface between the upwelling flow and the ambient fluid. At Fr = 2:2 the shear interaction between the rising and falling flow streams becomes important as it drives both large and small scale vortex structures. Large scale structures draw ambient fluid into the fountain while small scale structures exchange mass between the up flow and down flow. Periodic ejection of mass from the top of the fountain is shown to be an important dynamic in the flow. The results provided here can assist in analytical model development.

Item ID: 4810
Item Type: Article (Refereed Research - C1)
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ISSN: 1446-8735
Funders: Australian Research Council
Date Deposited: 30 Jul 2009 01:44
FoR Codes: 09 ENGINEERING > 0915 Interdisciplinary Engineering > 091504 Fluidisation and Fluid Mechanics @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970109 Expanding Knowledge in Engineering @ 60%
97 EXPANDING KNOWLEDGE > 970102 Expanding Knowledge in the Physical Sciences @ 40%
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