Self-Excited Oscillations of a Circular Disk Rotating in Air.

Yasuda, Kimihiko; Torii, Takao; Shimizu, Toshihiko

doi:10.1299/jsmec1988.35.347

Cited by 16 publications

(3 citation statements)

References 16 publications

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“…It is because the nonsymmetric stiffness, generated by the radial component of the airflow in the lubrication film, stiffens the disk. Yasuda et al [ 12 ] proposed that the aerodynamic force on a disk rotating in an infinite medium can be written in terms of the so-called lift and damping forces whose models can be characterized as rotating damping. They assumed that the ratio between the lift and damping force was proportional to rotational speed.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Sensing and Feedback Control for Vibration/Flutter of Rotating Disk by PZT Actuators via Air Coupled Pressure

Yan

Xü

Han

et al. 2011

Sensors

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In this paper, a feedback control mechanism and its optimization for rotating disk vibration/flutter via changes of air-coupled pressure generated using piezoelectric patch actuators are studied. A thin disk rotates in an enclosure, which is equipped with a feedback control loop consisting of a micro-sensor, a signal processor, a power amplifier, and several piezoelectric (PZT) actuator patches distributed on the cover of the enclosure. The actuator patches are mounted on the inner or the outer surfaces of the enclosure to produce necessary control force required through the airflow around the disk. The control mechanism for rotating disk flutter using enclosure surfaces bonded with sensors and piezoelectric actuators is thoroughly studied through analytical simulations. The sensor output is used to determine the amount of input to the actuator for controlling the response of the disk in a closed loop configuration. The dynamic stability of the disk-enclosure system, together with the feedback control loop, is analyzed as a complex eigenvalue problem, which is solved using Galerkin’s discretization procedure. The results show that the disk flutter can be reduced effectively with proper configurations of the control gain and the phase shift through the actuations of PZT patches. The effectiveness of different feedback control methods in altering system characteristics and system response has been investigated. The control capability, in terms of control gain, phase shift, and especially the physical configuration of actuator patches, are also evaluated by calculating the complex eigenvalues and the maximum displacement produced by the actuators. To achieve a optimal control performance, sizes, positions and shapes of PZT patches used need to be optimized and such optimization has been achieved through numerical simulations.

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Section: Introductionmentioning

confidence: 99%

Optimization of Sensing and Feedback Control for Vibration/Flutter of Rotating Disk by PZT Actuators via Air Coupled Pressure

Yan

Xü

Han

et al. 2011

Sensors

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“…Yasuda et al 4) performed a theoretical as well as an experimental study for the self-excited vibrations of a flexible disk rotating in air. Firstly, they analyzed the free vibrations of the disk without the effect of air and then the vibrations of the disk in air were analyzed.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulations of a Flexible Disk Rotating Close to a Rigid Rotating Wall

Gad

Rhim

2008

jjap

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In this paper, we present a numerical study about the dynamics of a flexible disk rotating close to a rigid rotating wall. Two new types of flat stabilizers, co-rotating and counter-rotating flat stabilizers, are introduced besides the well-known fixedstabilizer type which has been studied extensively. The 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 finite volume method (FVM) and solved numerically with semi-implicit method for pressure-linked equations (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 transient numerical simulation is performed to compare the stability boundaries of 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.

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“…Hosaka and Crandall 2) performed a single-mode analysis to obtain a rough estimate for the critical speed of a flexible disk coupled to thin air film and they found that the instability appears when the relative velocity between the disk and the average air flow in the fluid film is larger than the traveling wave velocity of the disk vibration and the same conclusion was obtained later by Huang and Mote. 3) The self-excited vibrations of a flexible disk rotating in air were investigated both experimentally and numerically by Yasuda et al 4) and they found that the vibrations of the disk in air propagate as forward and backward traveling waves and the later becomes of self-excited nature at sufficiently high speeds. Recently, Aman et al [5][6][7] developed a flexible optical disk (FOD) system which can achieve a small axial run out of the disk through simplified stabilizer control.…”

mentioning

confidence: 99%

Experimental and Numerical Study on the Dynamic Behavior of a Spinning Flexible Disk Close to a Rotating Rigid Wall

Gad

Rhim

2009

jjap

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In the present work, the behavior of a flexible disk rotating close to a fixed, a co-rotating, and a counter rotating flat-stabilizers in open air is investigated both experimentally and numerically. The Navier-Stokes equations along with the continuity equation representing the flow in the air-film are discretized using the finite volume method and solved numerically with the SIMPLE algorithm. An experimental test-rig is designed to investigate the effects of the rotation speed, the initial gap height and the inlet-hole size on the flexible disk displacement and its vibration amplitude. Finally, a comparison between the experimental and the numerical results is made.

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Self-Excited Oscillations of a Circular Disk Rotating in Air.

Cited by 16 publications

References 16 publications

Optimization of Sensing and Feedback Control for Vibration/Flutter of Rotating Disk by PZT Actuators via Air Coupled Pressure

Optimization of Sensing and Feedback Control for Vibration/Flutter of Rotating Disk by PZT Actuators via Air Coupled Pressure

Numerical Simulations of a Flexible Disk Rotating Close to a Rigid Rotating Wall

Experimental and Numerical Study on the Dynamic Behavior of a Spinning Flexible Disk Close to a Rotating Rigid Wall

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