Relations expressing the effects of roughness orientations θi and flow behavior index n of the power-law fluid on the flow factors of area-distributed random roughness in hydrodynamic lubrication are derived. By using a mapping function, the generalized average Reynolds equation contains non-diagonal terms, and the flow factor tensor is symmetrical but not necessarily diagonal according to the coordinate system. Finally, the conditions that two rough surfaces act as though they were perfectly smooth are discussed for some particular combinations. [S0742-4787(00)01604-0]

Issue Section:
Technical Briefs
Keywords:
rheology, mechanical contact, shear flow, lubrication, tribology, rough surfaces, surface topography, viscosity
Topics:
Flow (Dynamics), Rheology, Surface roughness, Tensors, Lubrication
1.
Hughes
,
G. D.
, and
Bush
,
A. W.
,
1993
, “
An Average Reynolds Equation for non-Newtonian Fluids in EHL Line Contacts
,”
ASME J. Tribol.
,
115
, pp.
666
–
669
.
2.
Chang
,
L.
,
1992
, “
Traction in Thermal Elastohydrodynamic Lubrication of Rough Surfaces
,”
ASME J. Tribol.
,
114
, pp.
186
–
191
.
3.
Li
,
W. L.
,
Weng
,
C. I.
, and
Hwang
,
C. C.
,
1995
, “
Effects of Roughness Orientation on Thin Film Lubrication of a Magnetic Recording System
,”
J. Phys. D: Applied Physics
,
28
, pp.
1011
–
1021
.
4.
Li
,
W. L.
, and
Weng
,
C. I.
, and
Hwang
,
C. C.
,
1997
, “
An Average Reynolds Equation for non-Newtonian Fluid, With Application to the Lubrication of the Magnetic Head-Disk Interface
,”
STLE Tribol. Trans.
,
40
, pp.
111
–
119
.
5.
Li
,
W. L.
,
Weng
,
C. I.
, and
Lue
,
J. I.
,
1996
, “
Surface Roughness Effects in Journal Bearing With non-Newtonian Lubricants
,”
STLE Tribol. Trans.
,
39
, pp.
819
–
826
.
6.
Li
,
W. L.
,
1998
, “
Surface Roughness Effects in Hydrodynamic Lubrication Involving the Mixture of Two Fluids
,”
ASME J. Tribol.
,
120
, pp.
772
–
780
.
7.
Elrod
,
H. G.
,
1973
, “
Thin-Film Lubrication Theory for Newtonian Fluids With Surface Processing Striated Roughness or Grooving
,”
ASME J. Lubr. Technol.
,
95
, pp.
484
–
489
.
8.
Elrod
,
H. G.
,
1979
, “
A General Theory for Laminar Lubrication With Reynolds Roughness
,”
ASME J. Lubr. Technol.
,
101
, pp.
8
–
14
.
9.
Tonder
,
K.
,
1977
, “
Mathematical Verification of the Applicability of Modified Reynolds Equation to Striated Rough Surfaces
,”
Wear
,
44
No.
2
, pp.
329
–
343
.
10.
Tonder
,
K.
,
1986
, “
The Lubrication of Unidirectional Striated Roughness: Consequences for Some General Roughness Theories
,”
ASME J. Tribol.
,
108
, pp.
167
–
170
.
11.
Lo
,
S. W.
,
1992
, “
On the Effects of Roughness Orientation—A Mapping and Double Scale Analysis of Flow Factors
,”
ASME J. Tribol.
,
114
, pp.
747
–
754
.
12.
Patir
,
N.
, and
Cheng
,
H. S.
,
1978
, “
An Average Flow Model for Determining Effects of Three-Dimensional Roughness on Partial Hydrodynamic Lubrication
,”
ASME J. Lubr. Technol.
,
100
, pp.
12
–
17
.
13.
Tripp
,
J. H.
,
1983
, “
Surface Roughness Effects in Hydrodynamic Lubrication: The Flow Factor Method
,”
ASME J. Lubr. Technol.
,
105
, pp.
458
–
465
.
14.
Peklenik
,
J.
,
1967
–68, “
New Developments in Surface Characterization and Measurements by Means of Random Process Analysis
,”
Proc. ImechE
,
182
, Part 3K, pp.
108
–
126
.
Copyright © 2000
 by ASME
You do not currently have access to this content.