Experimental study on the intrusion and stratification produced by confined laminar and turbulent round fountains

Dong, Liqiang, Lin, Wenxian, and Khatamifar, Mehdi (2021) Experimental study on the intrusion and stratification produced by confined laminar and turbulent round fountains. International Journal of Heat and Fluid Flow, 89. 108785. pp. 1-26.

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Abstract

In this paper, high-speed cameras and flow visualization techniques are used to investigate the behavior of the ‘fountain filling box’ flow resulted from releasing a round fountain in a homogeneous quiescent fluid in a cylindrical container over the ranges of 1.0⩽Fr⩽20.0,102⩽Re⩽1502, and 27.9⩽λ⩽48.75, where Fr,Re and λ are the Froude number, the Reynolds number, and the dimensionless radius of the container, respectively, with λ non-dimensionalized by the fountain source radius. The results show the transition of the flow behavior of the fountain and its secondary flows (i.e., the intrusion, reversed flow and stratification) from laminar to turbulent with increasing Fr, and turbulence of the flow strengthened with increasing Re. For intermediate (e.g., Fr=3.0) and forced turbulent fountains (e.g., Fr=5.0, 8.0, 15.0) with a specific λ, the non-dimensionalized time-scale for the intrusion front to impinge upon the sidewall, τw, is nearly constant for Re≳500. This is because the secondary intrusion flow is dominated by the wall-jet and buoyancy-inertial regimes where the non-dimensionalized intrusion front velocity, vi, is only time-dependent (vi~τ-1/2) or time-dependent but also under the influence of Fr (vi~Fr-1/2τ-1/4). However, τw for the fountains of Re≲204 is significantly different, which may result from the change in the dominant regime for the intrusion or the interaction between the upflow, downflow of the fountain and the ambient fluids. Furthermore, it is found that the non-dimensionalized quasi-steady development rate of the stratification, vs, increases with Fr, but decreases with Re, since the diffusion effect is suppressed with decreasing Fr or increasing Re.

Item ID: 66224
Item Type: Article (Research - C1)
ISSN: 1879-2278
Keywords: Filling box; Laminar round fountain; Turbulent round fountain; Intrusion; Stratification
Copyright Information: © 2021 Elsevier Inc. All rights reserved.
Funders: Australian Research Council, James Cook University (JCU)
Date Deposited: 19 Apr 2021 01:15
FoR Codes: 40 ENGINEERING > 4012 Fluid mechanics and thermal engineering > 401205 Experimental methods in fluid flow, heat and mass transfer @ 50%
40 ENGINEERING > 4012 Fluid mechanics and thermal engineering > 401208 Geophysical and environmental fluid flows @ 50%
SEO Codes: 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280110 Expanding knowledge in engineering @ 100%
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