Study of a flexible disk rotating close to a rigid rotating wall considering fluid inertia effects

Abstract

The present study is a numerical simulation about the dynamics of a flexible disk coupled to thin air film and rotating close to a rigid rotating wall. The idea of a flexible disk rotating in a close proximity of a rigid rotating wall is introduced and studied with two new types of flat stabilizers, co-rotating and counter-rotating flat stabilizers, besides the well-known fixed-stabilizer type which has been studied extensively in earlier works. In the present study, the flexible disk is modeled using linear plate theory and the air flow between the flexible disk and the rigid wall is modeled using Navier–Stokes and continuity equations. The flow equations are discretized using cell centered finite volume method (FVM) and solved numerically with the SIMPLE algorithm, while the spatial terms in the disk model are discretized using finite difference method (FDM) and time integration is performed using fourth-order Runge–Kutta method. The effect of inertia and coriollis forces on the disk displacement and air-film pressure is studied, also the dependence of these forces on the rotation speed, initial gap size and inlet-hole radius is investigated. A transient numerical code is developed to compare the stability boundaries for the different types of flat stabilizer at a wide range of circumferential mode numbers. The numerical results showed an improved stability of the flexible disk when rotating close to a counter-rotating flat stabilizer compared with co-rotating and fixed flat stabilizers.