Investigation of Slider Vibrations and Vibration Mode Changes in Helium-Air Gas Mixtures

2014 ◽  
Author(s):  
Zhengqiang Tang ◽  
Frank E. Talke
Keyword(s):  
Numerical Model ◽  
Physical Properties ◽  
Free Path ◽  
Frequency Analysis ◽  
Vibration Mode ◽  
Mean Free Path ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
Air Bearing ◽  
Pitch Mode

A numerical model for the simulation of slider vibrations in helium-air gas mixtures has been developed. The physical properties of the helium-air gas mixture, such as density, mean free path and viscosity, were determined to calculate the dynamic flying characteristics of a slider using the CMRR air bearing simulator. Frequency analysis shows that the helium percentage in the gas mixture can shift the second pitch mode of the slider to a higher frequency.

Elastohydrodynamic Lubrication of Air-Lubricated Rollers

1996 ◽  
Vol 118 (3) ◽  
pp. 623-628 ◽  
Author(s):  
Y. B. Chang ◽  
F. W. Chambers ◽  
J. J. Shelton
Keyword(s):  
Numerical Model ◽  
Film Thickness ◽  
Free Path ◽  
Close Contact ◽  
Slip Flow ◽  
Elastohydrodynamic Lubrication ◽  
Mean Free Path ◽  
Pressure Profiles ◽  
The Mean ◽  
Air Film

The lubricating air film between two rotating rollers in close contact was studied numerically. The numerical model used in this study accounts for the effects of air compressibility, material deformation, and the slip flow which occurs when the air film thickness is not much larger than the mean-free-path of the air molecules. The air film profiles and the pressure profiles for the nip region between the rollers were calculated. It was found that the calculated air film thicknesses are lower than predicted by the liquid elastohydrodynamic calculation. From this study, equations for the minimum air film thickness, the air film thickness at the center of contact, and the amount of air that passes through the nip were obtained. This study has application to the prediction of the amount of air entrained in a winding roll.

scholarly journals Unified gas-kinetic wave-particle methods IV: multi-species gas mixture and plasma transport

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Chang Liu ◽  
Kun Xu
Keyword(s):  
Free Path ◽  
Cell Size ◽  
Knudsen Number ◽  
Mean Free Path ◽  
Plasma Transport ◽  
Gas Mixture ◽  
Time Step ◽  
Flow Physics ◽  
Asymptotic Complexity ◽  
The Continuum

AbstractIn this paper, we extend the unified gas-kinetic wave-particle (UGKWP) methods to the multi-species gas mixture and multiscale plasma transport. The construction of the scheme is based on the direct modeling on the mesh size and time step scales, and the local cell’s Knudsen number determines the flow physics. The proposed scheme has the multiscale and asymptotic complexity diminishing properties. The multiscale property means that according to the cell’s Knudsen number the scheme can capture the non-equilibrium flow physics when the cell size is on the kinetic mean free path scale, and preserve the asymptotic Euler, Navier-Stokes, and magnetohydrodynamics (MHD) when the cell size is on the hydrodynamic scale and is much larger than the particle mean free path. The asymptotic complexity diminishing property means that the total degrees of freedom of the scheme reduce automatically with the decreasing of the cell’s Knudsen number. In the continuum regime, the scheme automatically degenerates from a kinetic solver to a hydrodynamic solver. In the UGKWP, the evolution of microscopic velocity distribution is coupled with the evolution of macroscopic variables, and the particle evolution as well as the macroscopic fluxes is modeled from a time accumulating solution of kinetic scale particle transport and collision up to a time step scale. For plasma transport, the current scheme provides a smooth transition from particle-in-cell (PIC) method in the rarefied regime to the magnetohydrodynamic solver in the continuum regime. In the continuum limit, the cell size and time step of the UGKWP method are not restricted by the particle mean free path and mean collision time. In the highly magnetized regime, the cell size and time step are not restricted by the Debye length and plasma cyclotron period. The multiscale and asymptotic complexity diminishing properties of the scheme are verified by numerical tests in multiple flow regimes.

Inelastic mean free path and phase-shift determinations in NiO, using EXELFS

1993 ◽  
Vol 3 (7) ◽  
pp. 1649-1659
Author(s):  
Mohammad A. Tafreshi ◽  
Stefan Csillag ◽  
Zou Wei Yuan ◽  
Christian Bohm ◽  
Elisabeth Lefèvre ◽  
...  
Keyword(s):  
Phase Shift ◽  
Free Path ◽  
Mean Free Path ◽  
Inelastic Mean Free Path

THE MAGNETIC ANISOTROPY OF Ni AND THE MEAN FREE PATH OF THE ELECTRONS

1971 ◽  
Vol 32 (C1) ◽  
pp. C1-539-C1-540 ◽  
Author(s):  
K. HAUSMANN ◽  
M. WOLF
Keyword(s):  
Magnetic Anisotropy ◽  
Free Path ◽  
Mean Free Path ◽  
The Mean

The measurement of mean free path λs using a slowing down time lead spectrometer in the 1–10 eV energy region

1968 ◽  
Vol 22 (4) ◽  
pp. 261-262
Author(s):  
M.P. Navalkar ◽  
K. Chandramoleshwar ◽  
D.V.S. Ramkrishna
Keyword(s):  
Free Path ◽  
Energy Region ◽  
Mean Free Path ◽  
Slowing Down ◽  
Time Lead

scholarly journals Controllable transport mean free path of light in xerogel matrixes embedded with polystyrene spheres

2009 ◽  
Vol 17 (9) ◽  
pp. 6975 ◽  
Author(s):  
Boris P. Bret ◽  
Nuno J. Couto ◽  
Mariana Amaro ◽  
Eduardo J. Nunes-Pereira ◽  
Michael Belsley
Keyword(s):  
Free Path ◽  
Mean Free Path ◽  
Polystyrene Spheres

An experimental method for calibration of the plasmon mean free path

2009 ◽  
Vol 236 (3) ◽  
pp. 165-173 ◽  
Author(s):  
H. MELTZMAN ◽  
Y. KAUFFMANN ◽  
P. THANGADURAI ◽  
M. DROZDOV ◽  
M. BARAM ◽  
...  
Keyword(s):  
Experimental Method ◽  
Free Path ◽  
Mean Free Path
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