Direct numerical simulation and analysis of transitional fountain flows

Luo, Chuan-xu, Lin, Wen-xian, Liu, Tao, Gao, Wen-feng, Li, Ming, Ma, Yu, and Zheng, Qin-hong (2008) Direct numerical simulation and analysis of transitional fountain flows. Journal of Hydrodynamics, 23 (3). pp. 244-255.

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Fountains with moderate Froude (Fr) and Reynolds (Re) numbers are of interest, especially for understanding the mechanism of turbulence and entrainment in the early stages of turbulent fountains. However there has been little investigation work to be done about the behavior of these transitional fountains. In this paper, the transient behavior of axisymmetric fountains with 19<"1S1O and lO(r.;;R~lOOO was studied by direct numerical simulation. It is found that when R~OO, there is little mixing between the downflow of the fountain and the ambient, even for Fr=8. However, when Re~OO, the mixing between the fountain downflow and the ambient becomes stronger, indicating that the entrainment and the turbulence are mainly due to Reynolds number and the contribution from Fr number is much smaller, and the mixing becomes very strong especially when Re~400. The maximum fountain penetration height fluctuates, even when the flow reaches the quasi-steady state, due to the interaction between the downflow and the bottom boundary and/or the entrainment between the downflow and the ambient, with its averaged value scales to F?12 Rell4 for 1 <FISS and I O(r.;;R~SOO.

Item ID: 9447
Item Type: Article (Research - C1)
ISSN: 1000-4874
Keywords: fountain; direct numerical simulation; transitional regime; turbulence; entrainment
Funders: 973 Basic Research Scheme, China; National Natural Science Foundation, China; Yunnan Provincial Science Foundation, China
Date Deposited: 02 Jun 2010 02:04
FoR Codes: 09 ENGINEERING > 0915 Interdisciplinary Engineering > 091504 Fluidisation and Fluid Mechanics @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970109 Expanding Knowledge in Engineering @ 70%
97 EXPANDING KNOWLEDGE > 970102 Expanding Knowledge in the Physical Sciences @ 30%
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