|Title:||Onset of plume convection in mushy layers||Authors:||Chung, C.A.
|Issue Date:||2000||Publisher:||臺北市:國立臺灣大學應用力學研究所||Journal Volume:||vol. 408||Start page/Pages:||-||Source:||Journal of Fluid Mechanics||Abstract:||
A weakly nonlinear analysis is employed to investigate the onset of plume convection
in the mushy layer of a binary solution directionally solidied from below.
An improved mathematical model including the constant pressure condition at the
melt/mush interface is applied to analytically analyse the nonlinear behaviour of
the convection. Results show that, due to the consideration of the constant pressure
condition at the interface, the present analytical results are much better in comparison
with the experiments than those obtained by previous studies, in which the
no-vertical-flow condition at the interface was considered. It is also shown that the
bifurcation to three-dimensional hexagon convection, corresponding to the onset of
plume convection, is subcritical. For the case of small concentration ratio C (equation
(5b)) the channel of the plume is generated at the top of the mush and grows
downwards into the mush. For the case of large C, the channel may be generated
at the interior of the mush and grow upwards to the top of the mush. The possible
parameter regime in which the flow is of a stable down-centre hexagon is discussed.
|Appears in Collections:||應用力學研究所|
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