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The effect of pressure fluctuations on the shapes of thinning liquid curtains

Published online by Cambridge University Press:  15 January 2021

Bridget M. Torsey*
Affiliation:
School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY14623, USA
Steven J. Weinstein
Affiliation:
School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY14623, USA Department of Chemical Engineering, Rochester Institute of Technology, Rochester, NY14623, USA
David S. Ross
Affiliation:
School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY14623, USA
Nathaniel S. Barlow
Affiliation:
School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY14623, USA
*
Email address for correspondence: bmt5558@rit.edu

Abstract

We consider the time-dependent response of a gravitationally thinning inviscid liquid sheet (a coating curtain) leaving a vertical slot to sinusoidal ambient pressure disturbances. The theoretical investigation employs the hyperbolic partial differential equation developed by Weinstein et al. (Phys. Fluids, vol. 9, issue 12, 1997, pp. 3625–3636). The response of the curtain is characterized by the slot Weber number, $W_{e_0} = \rho q V/2\sigma$, where $V$ is the speed of the curtain at the slot, $q$ is the volumetric flow rate per unit width, $\sigma$ is the surface tension and $\rho$ is the fluid density. Flow disturbances travel along characteristics with speeds relative to the curtain of $\pm \sqrt {uV/W_{e_0}}$, where $u = \sqrt {V^{2} + 2gx}$ is the curtain speed at a distance $x$ downstream from the slot. Here g is the acceleration of gravity. When the flow is subcritical ($W_{e_0} < 1$), upstream travelling disturbances near the slot affect the curtain centreline, and the slope of the curtain centreline at the slot oscillates with an amplitude that is a function of $W_{e_0}$. In contrast, all disturbances travel downstream in supercritical curtains ($W_{e_0} > 1$) and the slope of the curtain at the slot is vertical. Here, we specifically examine the curtain response under supercritical and subcritical flow conditions near $W_{e_0} = 1$ to deduce whether there is a substantial change in the overall shape and magnitude of the curtain responses. Despite the local differences in the curtain solution near the slot, we find that subcritical and supercritical curtains have similar responses for all imposed sinusoidal frequencies.

Type
JFM Papers
Copyright
© The Author(s), 2021. Published by Cambridge University Press

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References

REFERENCES

Baird, M.H.I. & Davidson, J.F. 1962 Annular jets-I: fluid dynamics. Chem. Engng Sci. 17 (6), 467472.CrossRefGoogle Scholar
Binnie, A.M. 1974 Resonating waterfalls. Proc. R. Soc. Lond. A 339 (1619), 435449.Google Scholar
Brown, D.R. 1961 A study of the behaviour of a thin sheet of moving liquid. J. Fluid Mech. 10 (2), 297305.CrossRefGoogle Scholar
Brunet, P., Christophe, C. & Laurent, L. 2004 Transonic liquid bells. Phys. Fluids 16 (7), 26682678.CrossRefGoogle Scholar
Clarke, A., Weinstein, S.J., Moon, A.G. & Simister, E.A. 1997 Time-dependent equations governing the shape of a two-dimensional liquid curtain. Part 2. Experiment. Phys. Fluids 9 (12), 36373644.CrossRefGoogle Scholar
Clarke, N.S. 1968 Two-dimensional flow under gravity in a jet of viscous liquid. J. Fluid Mech. 31 (3), 481500.Google Scholar
De Luca, L. & Costa, M. 1997 Stationary waves on plane liquid sheets falling vertically. Eur. J. Mech. B/Fluids 16 (1), 7588.Google Scholar
De Rosa, F., Girfoglio, M. & de Luca, L. 2014 Global dynamics analysis of nappe oscillation. Phys. Fluids 26 (12), 122109.CrossRefGoogle Scholar
Finnicum, D.S., Weinstein, S.J. & Ruschak, K.J. 1993 The effect of applied pressure on the shape of a two-dimensional liquid curtain falling under the influence of gravity. J. Fluid Mech. 255, 647665.CrossRefGoogle Scholar
Georgiou, G.C., Papanastasiou, T.C. & Wilkes, J.O. 1988 Laminar Newtonian jets at high Reynolds number and high surface tension. AIChE Journal 34, 9.Google Scholar
Girfoglio, M., De Rosa, F., Coppola, G. & De Luca, L. 2017 Unsteady critical liquid sheet flows. J. Fluid Mech. 821, 219247.CrossRefGoogle Scholar
Hildebrand, F.B. 2003 Advanced Calculus for Applications. Textbook Publishers.Google Scholar
Hopwood, F.L. 1952 Water bells. Proc. Phys. Soc. B 65 (1), 25.CrossRefGoogle Scholar
John, F. 2012 Partial Differential Equations. Springer.Google Scholar
Lance, G.N. & Perry, R.L. 1953 Water bells. Proc. Phys. Soc. B 66 (12), 10671072.CrossRefGoogle Scholar
Lax, P.D. 2006 Hyperbolic Partial Differential Equations. Courant Institute of Mathematical Sciences.Google Scholar
de Luca, L. 1999 Experimental investigation of the global instability of plane sheet flows. J. Fluid Mech. 399, 355376.CrossRefGoogle Scholar
Mori, H., Nagamine, T., Ito, R. & Sato, Y. 2012 Mechanism of self-excited vibration of a falling water sheet. Nihon Kikai Gakkai Ronbunshu, C Hen/Trans. Japan Soc. Mech. Engrs C 78 (792), 27202732.Google Scholar
Paramati, M. & Tirumkudulu, M.S. 2016 Open water bells. Phys. Fluids 28 (3), 032105.CrossRefGoogle Scholar
Ramos, J.I. 1988 Liquid curtains. I. Fluid mechanics. Chem. Engng Sci. 43 (12), 31713184.Google Scholar
Ramos, J.I. 1997 Analysis of annular liquid membranes and their singularities. Meccanica 32 (4), 279293.CrossRefGoogle Scholar
Ramos, J.I. 2003 Oscillatory dynamics of inviscid planar liquid sheets. Appl. Maths Comput. 143 (1), 109144.CrossRefGoogle Scholar
Ruschak, K.J. 1980 A method for incorporating free boundaries with surface tension in finite element fluid-flow simulators. Intl J. Numer. Meth. Engng 15 (5), 639648.CrossRefGoogle Scholar
Sato, Y., Miura, S., Nagamine, T., Morii, S. & Ohkubo, S. 2007 Behavior of a falling water sheet. J. Environ. Engng 2 (2), 394406.CrossRefGoogle Scholar
Schmid, P. & Henningson, D.S. 2002 On the stability of a falling liquid curtain. J. Fluid Mech. 463, 163171.Google Scholar
Tillett, J.P.K. 1968 On the laminar flow in a free jet of liquid at high Reynolds numbers. J. Fluid Mech. 32 (2), 273292.CrossRefGoogle Scholar
Weinstein, S.J., Clarke, A., Moon, A.G. & Simister, E.A. 1997 Time-dependent equations governing the shape of a two-dimensional liquid curtain. Part 1. Theory. Phys. Fluids 9 (12), 36253636.CrossRefGoogle Scholar
Weinstein, S.J. & Ruschak, K.J. 2004 Coating flows. Annu. Rev. Fluid Mech. 36 (1), 2953.CrossRefGoogle Scholar