Reduction of flow-induced vibration and noise of an optical disk drive

Dynamic interaction of heat transfer, air flow and disc vibration of disc drives — Theoretical development and numerical analysis

“…They found that coalescence between the acoustic and structural modes could lead to flutter instability at supercritical speeds. Some researchers [5][6][7][8][9] treated the coupling dynamics of the fluid flow and rotating disc as fluid and structure interaction problems. With the Reynolds equation of lubrication for thin film flows, Naganathan et al [5] and Bajaj et al [6] studied flutter instability and the forced harmonic response of a flexible disc rotating near a rigid wall in the presence of air, and found that the rotating disc could undergo flutter instability when the speed of rotation was above a critical speed, as discovered by a number of researchers in the recent past.…”

“…Using Navier-Stokes and continuity equations, Gad and Rhim [7] investigated dynamics of a flexible disc coupled to thin air film and rotating close to a rigid rotating wall, and it was shown that the stability of the rotating flexible disc could be improved by a counter-rotating flat stabiliser. With the NavierStokes equations for an incompressible air flow of constant viscosity, Yuan et al [8] studied the self-excited vibration induced by fluid forces of a rotating, umbrella-shaped disc in an open shroud, and Cheng et al [9] designed several enclosure covers of an optical disc drive to improve the flow-induced vibration of rotating discs.…”

“…(3) The temperature distribution of the surrounding fluid was analysed in [10][11][12][14][15][16][17][18][19][20], but that of the rotating disc itself was ignored, although the dynamic characteristics of the rotating disc can be affected significantly by the thermal stresses induced by the disc temperature variation. (4) The numeric simulations of fluid flow and heat transfer were performed at only several prescribed disc speeds [6][7][8][9][10] due to the limitation of computation capacity, although a comprehensive investigation over a large continuous speed range is much more realistic and useful. (5) For computer hard/optical disc drives, although some related investigations [5][6][7][8][9] of fluid flow have been made on the vibration and flutter instability of a rotating disc, there is no study on the problem of heat transfer and thermoelastic dynamic coupling with the fluid flow induced by disc rotation.…”

“…(4) The numeric simulations of fluid flow and heat transfer were performed at only several prescribed disc speeds [6][7][8][9][10] due to the limitation of computation capacity, although a comprehensive investigation over a large continuous speed range is much more realistic and useful. (5) For computer hard/optical disc drives, although some related investigations [5][6][7][8][9] of fluid flow have been made on the vibration and flutter instability of a rotating disc, there is no study on the problem of heat transfer and thermoelastic dynamic coupling with the fluid flow induced by disc rotation.…”

“…(7)(8)(9) and illustrated in Figs. 1, 4 and 5; the natural frequencies of the rotating disc are solved and analysed under the thermal stresses induced by the disc temperature distribution, as indicated in Eqs.…”