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On the shapes of liquid curtains flowing from a non-vertical slot

Published online by Cambridge University Press:  26 October 2023

Alessandro Della Pia*
Affiliation:
Scuola Superiore Meridionale, Naples 80138, Italy Department of Industrial Engineering, University of Naples ‘Federico II’, Naples 80125, Italy
Michael G. Antoniades
Affiliation:
Department of Chemical Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
Eleni S. Ioannidis
Affiliation:
Department of Chemical Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
Zoe A. Wejko
Affiliation:
Department of Chemical Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
Nathaniel S. Barlow
Affiliation:
School of Mathematics and Statistics, Rochester Institute of Technology, Rochester, NY 14623, USA
Matteo Chiatto
Affiliation:
Department of Industrial Engineering, University of Naples ‘Federico II’, Naples 80125, Italy
Steven J. Weinstein
Affiliation:
Department of Chemical Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA School of Mathematics and Statistics, Rochester Institute of Technology, Rochester, NY 14623, USA
Luigi de Luca
Affiliation:
Department of Industrial Engineering, University of Naples ‘Federico II’, Naples 80125, Italy
*
Email address for correspondence: alessandro.dellapia@unina.it

Abstract

A theoretical and experimental investigation of two-dimensional (2-D) liquid curtains (gravitationally thinning liquid sheets) is provided under conditions where the curtain issues from a thin slot whose centreline is inclined with respect to the vertical. This analysis is motivated in part by recent works where it has been proposed that oblique liquid curtains (those exiting a non-vertical slot) may bend upwards against gravity when the relevant Weber number at the slot is less than unity ($We <1$). By contrast, Weinstein et al. (J. Fluid Mech., vol. 876, 2019, R3) have proposed that such $We<1$ curtains must be vertical and downward falling regardless of the inclination of the slot. Under low-Reynolds-number ($Re$) conditions typical of liquid film coating operations, our experiments show that the curtain shape follows the classic ballistic (parabolic) trajectory in the supercritical regime ($We>1$). In subcritical conditions ($We<1$), experiments show that the downward-falling curtain is vertical except in a relatively small region near the slot, where the combined effects of viscosity and surface tension induce the so-called teapot effect. These experimental results are confirmed by 2-D numerical simulations, which predict the curtain behaviour ranging from highly viscous ($Re = O(1)$) to nearly inviscid conditions. The one-dimensional (1-D) inviscid model of Weinstein et al. is recast in a different form to facilitate comparisons with the 2-D model, and 1-D and 2-D results agree favourably for supercritical and subcritical conditions. Despite the large parameter range explored, we have found no evidence that upward-bending curtains exist in an oblique configuration.

Type
JFM Papers
Copyright
© The Author(s), 2023. Published by Cambridge University Press

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References

Acquaviva, M.R., Della Pia, A., Chiatto, M. & de Luca, L. 2023 Hole-driven dynamics of a three-dimensional gravitational liquid curtain. J. Fluid Mech. 968, A20.CrossRefGoogle Scholar
Benilov, E.S. 2019 Oblique liquid curtains with a large Froude number. J. Fluid Mech. 861, 328348.CrossRefGoogle Scholar
Benilov, E.S. 2023 Stability of oblique liquid curtains with surface tension. Phys. Fluids 35, 032116.CrossRefGoogle Scholar
Chiatto, M. & Della Pia, A. 2022 Natural frequency discontinuity of vertical liquid sheet flows at transcritical threshold. J. Fluid Mech. 945, A32.CrossRefGoogle Scholar
Clarke, A., Weinstein, S.J., Moon, A. & 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. 3, 481500.CrossRefGoogle Scholar
De Luca, L. 1999 Experimental investigation of the global instability of plane sheet flows. J. Fluid Mech. 399, 355376.CrossRefGoogle Scholar
De Luca, L. & Costa, M. 1997 Stationary waves on plane liquid sheets falling vertically. Eur. J. Mech. (B/Fluids) 16, 7588.Google Scholar
Della Pia, A., Chiatto, M. & de Luca, L. 2020 Global eigenmodes of thin liquid sheets by means of volume-of-fluid simulations. Phys. Fluids 32, 082112.CrossRefGoogle Scholar
Della Pia, A., Chiatto, M. & de Luca, L. 2021 Receptivity to forcing disturbances in subcritical liquid sheet flows. Phys. Fluids 33, 032113.CrossRefGoogle Scholar
Finnicum, D.S., Weinstein, S.J. & Rushak, 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
Francois, M.M., Cummins, S.J., Dendy, E.D., Kothe, D.B., Sicilian, J.M. & Williams, M.W. 2006 A balanced-force algorithm for continuous and sharp interfacial surface tension models within a volume tracking framework. J. Comput. Phys. 213 (1), 141173.CrossRefGoogle Scholar
Gascon, K.N., Antoniades, M.G. & Weinstein, S.J. 2019 Use of simplified surface tension measurements to determine surface excess: an undergraduate experiment. J. Chem. Educ. 96, 342347.CrossRefGoogle Scholar
Georgiou, G.C., Papanastasiou, T.C. & Wilkes, J.O. 1988 Laminar Newtonian jets at high Reynolds number and high surface tension. AIChE J. 34 (9), 15591562.CrossRefGoogle Scholar
Girfoglio, M., De Rosa, F., Coppola, G. & de Luca, L. 2017 Unsteady critical liquid sheet flows. J. Fluid Mech. 821, 219247.CrossRefGoogle Scholar
Hirt, C.W. & Nichols, B.D. 1981 Volume of fluid (VOF) method for the dynamics of free boundaries. J. Comput. Phys. 39 (1), 201225.CrossRefGoogle Scholar
van Hooft, J.A., Popinet, S., van Heerwaarden, C.C., van der Linden, S.J.A., de Roode, S.R. & van de Wiel, B.J.H. 2018 Towards adaptive grids for atmospheric boundary-layer simulations. Boundary-Layer Meteorol. 167 (3), 421443.CrossRefGoogle ScholarPubMed
Iyer, M., Casalinho, J., Seiwert, J., Wattiau, M. & Duval, H. 2021 Experimental study of a liquid film flowing over a perforation. AIChE J. 67, 11.CrossRefGoogle Scholar
Keller, J.B. & Weitz, M.L. 1957 Upward falling jets and surface tension. J. Fluid Mech. 2, 201203.CrossRefGoogle Scholar
Kistler, S.F. & Scriven, L.E. 1994 The teapot effect: sheet-forming flows with deflection, wetting and hysteresis. J. Fluid Mech. 263, 1962.CrossRefGoogle Scholar
Lin, S.P. & Roberts, G. 1981 Waves in a viscous liquid curtain. J. Fluid Mech. 112, 443458.CrossRefGoogle Scholar
Popinet, S. 2003 Gerris: a tree-based adaptive solver for the incompressible Euler equations in complex geometries. J. Comput. Phys. 190 (2), 572600.CrossRefGoogle Scholar
Popinet, S. 2009 An accurate adaptive solver for surface-tension-driven interfacial flows. J. Comput. Phys. 228 (16), 58385866.CrossRefGoogle Scholar
Ramos, J.I. 2003 Oscillatory dynamics of inviscid planar liquid sheets. Appl. Maths Comput. 143 (1), 109144.Google 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
Scardovelli, R. & Zaleski, S. 1999 Direct numerical simulation of free-surface and interfacial flow. Annu. Rev. Fluid Mech. 31 (1), 567603.CrossRefGoogle Scholar
Schmidt, S. & Oberleithner, K. 2020 Instability of forced planar liquid jets: mean field analysis and non linear simulation. J. Fluid Mech. 883, 138.CrossRefGoogle Scholar
Schmidt, S., Tammisola, O., Lesshafft, L. & Oberleithner, K. 2021 Global stability and nonlinear dynamics of wake flows with a two-fluid interface. J. Fluid Mech. 915, A96.CrossRefGoogle Scholar
Schweizer, P.M. 2021 Premetered coating methods: attractiveness and limitations. Springer.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
Torsey, B., Weinstein, S.J., Ross, D. & Barlow, N. 2021 The effect of pressure fluctuations on the shapes of thinning liquid curtains. J. Fluid Mech. 910, 114.CrossRefGoogle Scholar
Weinstein, S.J., Ross, D.S., Ruschak, K.J. & Barlow, N.S. 2019 On oblique liquid curtains. J. Fluid Mech. 876, R3.CrossRefGoogle Scholar
Weinstein, S.J. & Ruschak, K.J. 2004 Coating flows. Annu. Rev. Fluid Mech. 36, 2953.CrossRefGoogle Scholar

Della Pia et al. Supplementary Movie 1

Sequence of experimental curtain shapes as they undergo transition between supercritical and subcritical flows.

Download Della Pia et al. Supplementary Movie 1(Video)
Video 10.8 MB

Della Pia et al. Supplementary Movie 2

Sequence of experimental curtain shapes as they hey undergo transition between supercritical and subcritical flows (magnified near slot).

Download Della Pia et al. Supplementary Movie 2(Video)
Video 17.5 MB