On Mixed Squeeze Films of Infinite Width Plates

1991 ◽  
Vol 113 (2) ◽  
pp. 378-383
Author(s):  
Wu Chengwei
Keyword(s):  
Flow Model ◽  
Damping Coefficient ◽  
Squeeze Film ◽  
Average Flow ◽  
One Dimensional ◽  
Contact Rigidity ◽  
Squeeze Film Damping ◽  
Longitudinal Roughness ◽  
Roughness Amplitude ◽  
Average Flow Model

A mixed squeeze film model between two rough squeezing plates is established in the present paper. The squeeze behavior in the presence of full and partial fluid film between two rough surfaces is analyzed by using Patir and Cheng’s average flow model and Greenwood and Tripp’s roughness contact model. For one-dimensional squeeze films, transverse and isotropic surface roughness (γ ≤ 1) leads to an increasing squeeze film damping coefficient and a longer sinkage time in comparison with smooth surfaces. But, longitudinal roughness (γ > 1) leads to a decreasing squeeze film damping coefficient and a shorter sinkage time. When the roughness orientation parameter γ is kept constant, increasing roughness amplitude causes an early roughness contact and an increasing contact rigidity.

An Evaluation of the Average Flow Model [1] for Surface Roughness Effects in Lubrication

1980 ◽  
Vol 102 (3) ◽  
pp. 360-366 ◽  
Author(s):  
J. L. Teale ◽  
A. O. Lebeck
Keyword(s):  
Surface Roughness ◽  
Flow Model ◽  
Two Dimensional ◽  
Roughness Effects ◽  
Important Conclusion ◽  
Average Flow ◽  
One Dimensional ◽  
Dimensional Flow ◽  
Two Dimensional Flow ◽  
Average Flow Model

The average flow model presented by Patir and Cheng [1] is evaluated. First, it is shown that the choice of grid used in the average flow model influences the results. The results presented are different from those given by Patir and Cheng. Second, it is shown that the introduction of two-dimensional flow greatly reduces the effect of roughness on flow. Results based on one-dimensional flow cannot be relied upon for two-dimensional problems. Finally, some average flow factors are given for truncated rough surfaces. These can be applied to partially worn surfaces. The most important conclusion reached is that an even closer examination of the average flow concept is needed before the results can be applied with confidence to lubrication problems.

scholarly journals An Average Flow Model of the Reynolds Roughness Including a Mass-Flow Preserving Cavitation Model

2005 ◽  
Vol 127 (4) ◽  
pp. 793-802 ◽  
Author(s):  
Guy Bayada ◽  
Sébastien Martin ◽  
Carlos Vázquez
Keyword(s):  
Mass Flow ◽  
Numerical Experiments ◽  
Reynolds Equation ◽  
Flow Model ◽  
Two Dimensional ◽  
Scale Analysis ◽  
Cavitation Model ◽  
Average Flow ◽  
One Dimensional ◽  
Average Flow Model

An average Reynolds equation for predicting the effects of deterministic periodic roughness, taking Jakobsson, Floberg, and Olsson mass flow preserving cavitation model into account, is introduced based upon the double scale analysis approach. This average Reynolds equation can be used both for a microscopic interasperity cavitation and a macroscopic one. The validity of such a model is verified by numerical experiments both for one-dimensional and two-dimensional roughness patterns.

Damping Analysis of Asymmetrical Comb Accelerometer

2007 ◽  
Vol 353-358 ◽  
pp. 2597-2600 ◽  
Author(s):  
Wei Ping Chen ◽  
Zhen Gang Zhao ◽  
Xiao Wei Liu ◽  
Yu Min Lin
Keyword(s):  
Damping Ratio ◽  
Resonance Phenomenon ◽  
Damping Coefficient ◽  
Anodic Bonding ◽  
Squeeze Film ◽  
Frequency Bandwidth ◽  
Vibration Method ◽  
Capacitive Accelerometer ◽  
Squeeze Film Damping

The resonance phenomenon is suppressed by adjusting the damping of the comb accelerometer structure to widen the frequency bandwidth of the capacitive accelerometer. The capacitive accelerometer with asymmetrical combs, fabricated with DRIE and anodic bonding, is presented. The damping category of the accelerometer is introduced, in which the squeeze-film damping coefficient and the damping ratio factor are detailed. The damping ratio factor of the accelerometer, measured by a vibration method, is 0.17. The damping ratio factor of the optimized structure is calculated of 0.15 to 0.18 with the change of experiential modulus C from 25 to 30, theoretically.

Pressure and Shear Flow in a Rough Hydrodynamic Bearing, Flow Factor Calculation

1997 ◽  
Vol 119 (3) ◽  
pp. 549-555 ◽  
Author(s):  
L. Lunde ◽  
K. To̸nder
Keyword(s):  
Finite Element Method ◽  
Surface Roughness ◽  
Finite Element ◽  
Shear Flow ◽  
Reynolds Equation ◽  
Flow Model ◽  
The Finite Element Method ◽  
Average Flow ◽  
Hydrodynamic Bearing ◽  
Average Flow Model

The lubrication of isotropic rough surfaces has been studied numerically, and the flow factors given in the so-called Average Flow Model have been calculated. Both pressure flow and shear flow are considered. The flow factors are calculated from a small hearing part, and it is shown that the flow in the interior of this subarea is nearly unaffected by the bearing part’s boundary conditions. The surface roughness is generated numerically, and the Reynolds equation is solved by the finite element method. The method used for calculating the flow factors can be used for different roughness patterns.

A Simple Method to Calculate Contact Factor Used in Average Flow Model

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Fanming Meng ◽  
Q. Jane Wang ◽  
Diann Hua ◽  
Shuangbiao Liu
Keyword(s):  
Density Distribution ◽  
Probability Density ◽  
Method Validation ◽  
Present Method ◽  
Flow Model ◽  
Probability Density Distribution ◽  
Simple Method ◽  
Average Flow ◽  
Non Gaussian ◽  
Average Flow Model

The average flow model proposed by Patir and Cheng offers a great convenience for the analysis of rough surfaces in lubrication. The contact factor introduced by Wu and Zheng helps to solve a difficulty in local film evaluation using the average flow model. This paper reports a simple method to calculate the contact factor. Method validation is demonstrated by the comparison of the contact factors for Gaussian surfaces obtained with the present method and the fitting formula of Wu and Zheng. The proposed method cannot only easily compute the contact factor values for Gaussian surfaces; it can also be used for those of non-Gaussian and measured surfaces, especially those with unknown probability density distribution of the roughness height.

A mass-conservative average flow model based on finite element method for complex textured surfaces

2013 ◽  
Vol 56 (10) ◽  
pp. 1909-1919 ◽  
Author(s):  
Yi Xie ◽  
YongJian Li ◽  
ShuangFu Suo ◽  
XiangFeng Liu ◽  
JingHao Li ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Flow Model ◽  
Textured Surfaces ◽  
Average Flow ◽  
Model Based ◽  
Average Flow Model ◽  
Element Method
Sign in / Sign up

Export Citation Format

Share Document