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http://dx.doi.org/10.9725/kstle.2014.30.1.15

Sensitivity Analysis of Effective Viscosity Coefficients for Computing Characteristics of Ultrathin Gas Film Bearings  

Kim, Ui Han (School of Mechanical Engineering, Yonsei University)
Rhim, Yoon Chul (Dept. of Mechanical Engineering, Yonsei University)
Publication Information
Tribology and Lubricants / v.30, no.1, 2014 , pp. 15-20 More about this Journal
Abstract
A more accurate expression for effective viscosity is obtained using a linear regression of the data from Fukui-Kaneko's model, which are obtained through numerical calculations based on the linearized Boltzmann equation. Veijola and Turowski's expression is adopted as a base function for effective viscosity. The four coefficients in that equation are optimized, and sensitivity analysis is conducted for these coefficients. The results show that the coefficient for the first-order Knudsen number is the most accurate, whereas the coefficient in the exponential of the Knudsen number is the least accurate compared with Fukui-Kaneko's results. The expression for effective viscosity is accurate within 0.02% rms of Fukui-Kaneko's results for the inverse Knudsen numbers from 0.01 to 100 and surface accommodation coefficients ranging from 0.7 to 1.
Keywords
effective viscosity; knudsen number; slip boundary condition; linear regression; sensitivity analysis; surface accommodation coefficient; mean free path;
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