Unsteady laminar nonlinear slip flow of power law fluids in a microchannel is investigated. The nonlinear partial differential equation resulting from the momentum balance is solved with linear as well as nonlinear boundary conditions at the channel wall. We prove the existence of the weak solution, develop a semi-analytical solution based on the pseudo-spectral-Galerkin and Tau methods, and discuss the influence and effect of the slip coefficient and power law index on the time-dependent velocity profiles. Larger slip at the wall generates increased velocity profiles, and this effect is further enhanced by increasing the power law index. Comparatively, the velocity of the Newtonian fluid is larger and smaller than that of the power law fluid for the same value of the slippage coefficient if the power index is smaller and larger, respectively, than one.

References

1.
Larrode
,
F. E.
,
Housiadas
,
C.
, and
Drossinos
,
Y.
,
2000
, “
Slip-Flow Heat Transfer in Circular Tubes
,”
Int. J. Heat Mass Transfer
,
43
, pp.
2669
2680
.
2.
Renksizbulut
,
M.
,
Niazmand
,
H.
, and
Tercan
,
G.
,
2006
, “
Slip-Flow and Heat Transfer in Rectangular Microchannels With Constant Wall Temperature
,”
Int. J. Therm. Sci.
,
45
(
9
), pp.
870
881
.
3.
Duan
,
Z. P.
, and
Muzychka
,
Y. S.
,
2008
, “
Slip Flow Heat Transfer in Annular Microchannels With Constant Heat Flux
,”
ASME J. Heat Transfer
,
130
(
9
), p.
092401
.
4.
Akyildiz
,
F. T.
, and
Siginer
,
D. A.
,
2011
, “
Fully Developed Laminar Slip and No-Slip Flow in Rough Microtubes
,”
Z. Angew. Math. Phys.
,
62
(
4
), pp.
741
748
.
5.
Balmer
,
R. T.
, and
Fiorina
,
M. A.
,
1980
, “
Unsteady Flow of an Inelastic Power-Law Fluid in a Circular Tube
,”
J. Non-Newtonian Fluid Mech.
,
7
(
2–3
), pp.
189
198
.
6.
Schowalter
,
W. R.
,
1988
, “
The Behavior of Complex Fluids at Solid Boundaries
,”
J. Non-Newtonian Fluid. Mech.
,
29
, pp.
25
36
.
7.
Lauga
,
E.
,
Brenner
,
M.
, and
Stone
,
H.
,
2007
, “
Microfluids: The No Slip Boundary Conditions
,”
Handbook of Experimental Fluid Mechanics
,
Springer
, New York, pp.
1219
1240
.
8.
Denn
,
M. M.
,
2001
, “
Extrusion Instabilities and Wall Slip
,”
Ann. Rev. Fluid Mech.
,
33
(
1
), pp.
265
287
.
9.
Hatzikiriakos
,
S. G.
,
1993
, “
A Slip Model for Linear Polymers Based on Adhesive Failure
,”
Int. Polym. Process.
,
8
(
2
), pp.
135
142
.
10.
Hatzikiriakos
,
S. G.
,
2012
, “
Wall Slip of Molten Polymers
,”
Progr. Polym. Sci.
,
37
(
4
), pp.
624
643
.
11.
Hron
,
J.
,
Le Roux
,
C.
,
Málek
,
J.
, and
Rajagopal
,
K. R.
,
2008
, “
Flows of Incompressible Fluids Subject to Navier's Slip on the Boundary
,”
Comput. Math. Appl.
,
56
(
8
), pp.
2128
2143
.
12.
Potente
,
H.
,
Timmermann
,
K.
, and
Kurte-Jardin
,
M.
,
2006
, “
Description of the Pressure/Throughput Behavior of a Single-Screw Plasticating Unit in Consideration of Wall Slippage Effects for Non-Newtonian Material and 1-D Flow
,”
Int. Polym. Process.
,
21
(
3
), pp.
272
281
.
13.
Ferrás
,
L. L.
,
Nóbrega
,
J. M.
, and
Pinho
,
F. T.
,
2012
, “
Analytical Solutions for Newtonian and Inelastic Non-Newtonian Flows With Wall Slip
,”
J. Non-Newtonian Fluid Mech.
,
175–176
, pp.
76
88
.
14.
Ferrás
,
L. L.
,
Nóbrega
,
J. M.
, and
Pinho
,
F. T.
,
2012
, “
Analytical Solutions for Channel Flows of Phan–Thien–Tanner and Giesekus Fluids Under Slip
,”
J. Non-Newtonian Fluid Mech.
,
171–172
, pp.
97
105
.
15.
Zhao
,
C.
,
Zholkovskij
,
E.
,
Masliyah
,
J. H.
, and
Yang
,
C.
,
2008
, “
Analysis of Electroosmotic Flow of Power-Law Fluids in a Slit Microchannel
,”
J. Colloid Interface Sci.
,
326
(
2
), pp.
503
510
.
16.
Barkhordari
,
M.
, and
Etemad
,
S. G.
,
2007
, “
Numerical Study of Slip Flow Heat Transfer of Non-Newtonian Fluids in Circular Microchannels
,”
Int. J. Heat Fluid Flow
,
28
(
5
), pp.
1027
1033
.
17.
Damianou
,
Y.
,
Kaoullas
,
G.
, and
Georgiou
,
G. C.
,
2016
, “
Cessation of Viscoplastic Poiseuille Flow in a Square Duct With Wall Slip
,”
J. Non-Newtonian Fluid Mech.
,
233
, pp.
13
26
.
18.
Guermond
,
J.-L.
,
2007
, “
Faedo–Galerkin Weak Solutions of the Navier–Stokes Equations With Dirichlet Boundary Conditions
,”
Journal de Mathématiques Pures et Appliquées
,
88
(
1
), pp.
87
106
.
19.
Málek
,
J.
,
Rajagopal
,
K. R.
, and
Žabenský
,
J.
,
2016
, “
On Power-Law Fluids With the Power-Law Index Proportional to the Pressure
,”
Appl. Math. Lett.
,
62
, pp.
118
123
.
20.
Lanczos
,
C.
,
1938
, “
Trigonometric Interpolation of Empirical and Analytic Functions
,”
J. Math. Phys.
,
17
(
1–4
), pp.
123
199
.
21.
Ortiz
,
E. L.
,
1969
, “
The Tau Method
,”
SIAM J. Numer. Anal.
,
6
(
3
), pp.
480
492
.
22.
Gottlieb
,
D.
, and
Orszag
,
S. A.
,
1977
,
Numerical Analysis of Spectral Methods: Theory and Applications
,
SIAM
,
Philadelphia, PA
.
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