The influence of height on the spreading distance of axisymmetric jets impinging on a rigid surface

Luthfi Luthfi

Abstract


The influence of the domain height of negative buoyancy jets when impinging on a rigid surface has been investigated. The study was conducted numerically by applying the Computational Fluid Dynamics (CFD) method.  The numerical model consists of a set of Navier-Stokes equations together with an energy equation. The jet flow was modeled in a two-dimensional axisymmetric coordinate. The governing equations were solved in transient using the finite volume approach. The programming code for the numerical model was written in Fortran. The numerical simulations were run at Froude number Fr = 5.0; Reynolds number, Re = 200 and Prandtl number Pr = 7.0. The investigated parameter, the domain height was varied at around 8.8 ≤ H/X0 ≤ 10.2. The flow visualization created from simulation results has revealed the mystery behind the complex flow behavior in detail. Starting from the initial flow when the jet entered the domain to the complex flow pattern of the jet flow detaching from the top surface. Including when the downflow mixes with the upflow creating a recirculation area near the top surface and the bottom of the domain. The plot of the spreading distance over time shows that there is a maximum distance when the jet starts detaching from the top surface. Gradually, the distance decreases until reaching a fixed final distance when the jet flow reaches quasi-steady. The influence of the domain height that was investigated shows different flow patterns at different heights. The plot of final distances over the domain height shows that there is a nonlinear relationship. The regression equation created from the numerical data shows good agreement and accuracy.


Keywords


impinging jet; transient simulation; computational fluid dynamics; buoyancy and domain height

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References


L. J. Bloomfield and R. C. Kerr, Turbulent fountains in a stratified fluid, Journal of Fluid Mechanics, vol. 358, pp. 335-356, 1998.

L. J. Bloomfield and R. C. Kerr, A theoretical model of a turbulent fountain , Journal of Fluid Mechanics, vol. 424, pp. 197-216, 2000.

W. Lin and S. Armfield, Weak fountains in a stratified fluid, Physical Review, Vol 66, 066308, 2002.

W. Lin and S. Armfield, Direct simulation of weak axisymmetric fountains in a homogeneous fluid, Journal of Fluid Mechanics, vol. 403, pp. 67-88, 2000.

W. Lin and S. Armfield, The Reynolds and Prandtl number dependence of weak fountains, Computational Mechanics, vol. 31, pp. 379-389, 2003.

W. Lin and S. Armfield, Direct simulation of fountains with intermediate Froude and Reynolds number, ANZIAM Journal, vol. 45(E), pp. C66-C77, 2004.

W. Lin and S. Armfield, Onset of entrainment in transitional round fountains in a homogeneous fluid, International Journal of Heat and Mass Transfer, vol. 51, pp. 5226-5237, 2008.

N. Williamson, S. W. Armfield and W. Lin, Transition behavior of weak turbulent fountains. Journal of Fluid Mechanics, vol. 655, pp. 306-326, 2010.

N. Williamson, S. W. Armfield and W. Lin, Forced turbulent fountain flow behavior, Journal of Fluid Mechanics, vol. 671, pp. 535-558, 2011.

K. Kuruppu and C. J. Lemckert, Plunging radius of water fountains following impact on a rigid surface, Proceedings of 7th Australasian Heat and Mass Transfer Conference, pp. 195-200, 2000.

D. M. Holstein and C. J. Lemckert, Spreading of energetic submerged fountains impinging on a rigid surface, Proceedings of 14th Australasian Fluid Mechanics Conference, pp. 749-752, 2001.

C. J. Lemckert, Spreading radius of fountains after impinging a free surface, Proceedings of 15th Australasian Fluid Mechanics Conference, pp. 217-220, 2004.

C. J. Lemckert, Submerged fountains impinging on a smooth horizontal surface. Proceedings of 8th Australasian Heat and Mass Transfer Conference, pp. D10, 2005.

P. Cooper and G. R. Hunt, Impinging axisymmetric turbulent fountains, Physics of Fluid, vol. 19, pp. 117101, 2007.

S. E. Norris, A parallel Navier- Stokes solver for natural convection and free surface flow, PhD thesis, The University of Sydney, Australia, 2000.




DOI: http://dx.doi.org/10.30811/jpl.v20i1.2437

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