Cargill, D. and Fehribach, J. and Lin, TS and Please, Colin and Raymond, C. and Schwendeman, D. and Skorczewski, T. and Tilley, B. and Witelski, T. and Wrobel, J. and Wang, J. and Zhang, S. (2009) Homogenization of the Equations Governing the Flow Between a Slider and a Rough Spinning Disk. [Study Group Report]

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Abstract
We have analyzed the behavior of the flow between a slider bearing and a harddrive magnetic disk under two types of surface roughness. For both cases the length scale of the roughness along the surface is small as compared to the scale of the slider, so that a homogenization of the governing equations was performed.
For the case of longitudinal roughness, we derived a onedimensional lubricationtype equation for the leading behavior of the pressure in the direction parallel to the velocity of the disk. The coefficients of the equation are determined by solving linear elliptic equations on a domain bounded by the gap height in the vertical direction and the period of the roughness in the spanwise direction.
For the case of transverse roughness the unsteady lubrication equations were reduced, following a multiple scale homogenization analysis, to a steady equation for the leading behavior of the pressure in the gap. The reduced equation involves certain averages of the gap height, but retains the same form of the usual steady, compressible lubrication equations.
Numerical calculations were performed for both cases, and the solution for the case of transverse roughness was shown be in excellent agreement with a corresponding numerical calculation of the original unsteady equations.
Item Type:  Study Group Report 

Problem Sectors:  Materials Information and communication technology 
Study Groups:  US Workshop on Mathematical Problems in Industry > 25th MPI [Delaware 15/6/2009  19/6/2009] 
Company Name:  Hitachi 
ID Code:  270 
Deposited By:  Dr Kamel Bentahar 
Deposited On:  09 Dec 2009 18:12 
Last Modified:  29 May 2015 19:53 
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