Sains Malaysiana 42(7)(2013): 975–980
Travelling-Wave Similarity Solutions for an Unsteady
Shear-Stress-Driven
Dry Patch in a Flowing Film
(Penyelesaian Keserupaan Gelombang Menjalar bagi Aliran Tak Mantap
di Sekitar
Tompokan Kering yang Didorong oleh Tegasan Ricih)
Yazariah M.Yatim*
School of Mathematical Sciences,
Universiti Sains Malaysia, 11800 Penang, Malaysia
Brian R. Duffy & Stephen K. Wilson
Department of Mathematics and Statistics, University of
Strathclyde
G1 1XHGlasgow, United Kingdom
Diserahkan: 1 Februari 2012/Diterima: 16 Januari 2013
ABSTRACT
We investigate unsteady flow of a thin film of Newtonian fluid
around a symmetric slender dry patch moving with constant velocity on an
inclined planar substrate, the flow being driven by a prescribed constant shear
stress at the free surface of the film (which would be of uniform thickness in
the absence of the dry patch). We obtain a novel unsteady travelling-wave
similarity solution which predicts that the dry patch
has a parabolic shape and that the film thickness increases monotonically away
from the dry patch.
Keywords: Dry patch; similarity solution; thin-film
flow; travelling-wave
ABSTRAK
Kami mengkaji aliran tak mantap filem nipis
bendalir Newtonian di sekitar tompokan kering simetri yang bergerak dengan
halaju yang malar di atas substrat yang condong. Aliran tersebut didorong oleh
tegasan ricih yang malar pada permukaan bebas filem itu (yang mempunyai
ketebalan yang seragam sekiranya tompokan kering tidak wujud). Kami memperoleh penyelesaian keserupaan gelombang menjalar bagi
tompokan kering yang menunjukkan tompokan kering tersebut berbentuk parabola
dan ketebalan filem menjauhi tompokan kering didapati bertambah secara
monotonik.
Kata kunci: Aliran filem nipis; gelombang
menjalar; penyelesaian keserupaan; tompokan kering
RUJUKAN
Hartley, D.E. & Murgatroyd, W. 1964. Criteria
for the break-up of thin liquid layers flowing isothermally over solid surfaces.Int. J. Heat Mass Transfer 7:
1003-1015.
Murgatroyd, W. 1965. The role of shear and
form forces in the stability of a dry patch in two-phase film flow. Int. J.
Heat Mass Transfer 8: 297-301.
Podgorski,T.,
Flesselles, J-M. & Limat, L. 1999. Dry arches
within flowing films. Phys. Fluids 11: 845-852.
Podgorski, T., Flesselles,
J-M. &
Limat, L. 2001. Curvature of a dry patch boundary in a
flowing film. C.R. Acad. Sci., Ser IV 2: 1361-1367.
Ponter, A.B., Davies, G.A.,
Ross, T.K. & Thornley, P.G. 1967.The influence of mass transfer on liquid
film breakdown. Int. J. Heat Mass
Transfer 10: 349-359.
Rio, E., Daerr, A. &
Limat, L. 2004. Probing with a laser sheet
the contact angle distribution along a contact line. J. Colloid Interface
Sci. 269: 164-170.
Rio, E. & Limat, L. 2006. Wetting hysteresis of a dry patch
left inside a flowing film. Phys. Fluids 18:
032102-1–032102-8.
Sćbilleau, J.,
Lebon, L. & Limat, L. 2009. Stability of a dry patch in a
viscous flowing film. Eur. Phys. J. Special Topics 166: 139-142.
Wilson, S.K., Duffy, B.R. & Davis,
S.H. 2001. On a slender dry patch in a liquid
film draining under gravity down an inclined plane. Eur. J. Appl. Math. 12: 233-252.
Yatim, Y.M., Duffy, B.R. & Wilson, S.K. 2012. Travelling-wave similarity solutions for an unsteady gravity-driven
dry patch. In Progress in Industrial Mathematics at ECMI 2010.Heidelberg:
Springer-Verlag. pp. 441-447.
*Pengarang
untuk surat-menyurat; email: yazariahmy@usm.my
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