Browsing by Author "Yang, W. M."

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Instability analysis of modulated Taylor vortices
(2009)
Yang, W. M.
;
Lin, H. C.
;
機械工程學系
;
Department of Mechanical Engineering
This study investigates the instability analysis of modulated Taylor vortices flow by utilising a numerical method. Based on the consideration that the outer cylinder is fixed and the inner cylinder rotates at a non-zero averaged speed under varying modulated amplitudes and frequencies, the flow is converted from one-dimension Couette flow to Taylor vortices. When the modulated amplitude is greater than 1 and the rotation speed of the inner cylinder exceeds the threshold value for one-dimensional flow, the flow will be more stable at intermediate and high frequencies. When the modulated amplitude is sufficiently large and the inner cylinder rotates at medium frequency, subharmonic flow arises.
LOWEST STABILITY BOUNDARY ON FLOW OF CONCENTRIC ROTATING CYLINDERS
(2010-05-01)
Lin, H. C.
;
Yang, W. M.
;
機械工程學系
;
Department of Mechanical Engineering
In this study, we numerically investigate the lowest instability boundary of nonaxisymmetric Taylor vortex flow (TVF) for different axial wavenumbers. The variation in the axial wavenumber of a supercritical TVF can affect the instability of the flow, because the wavelength of a Taylor vortex is constant only when the flow is axisymmetrical. When the nonaxisymmetric TVF is transformed to a wavy vortex flow (WVF), the instability boundary is changed with the variation in the axial wavenumber. We carry out an instability analysis of the nonaxisymmetric TVF between two concentric rotating cylinders, which have a radius ratio of 0.88.
TRANSFORMATIONAL PHENOMENON IN THE FIELD OF TAYLOR-COUETTE FLOW
(2010-11-01)
Yang, W. M.
;
Lin, H. C.
;
機械工程學系
;
Department of Mechanical Engineering