Thermal convection of a viscoelastic fluid in an open-top porous layer   heated from below

doi:10.1016/j.jnnfm.2009.12.002

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	Thermal convection of a viscoelastic fluid in an open-top porous layer heated from below
	Niu, Jun ; Fu, Ceji ; Tan, Wenchang
刊名	非牛顿流体力学杂志
	2010
关键词	Viscoelastic fluid Thermal convection Porous medium OLDROYD-B FLUIDS INSTABILITY FLOW MEDIA
DOI	10.1016/j.jnnfm.2009.12.002
英文摘要	Buoyancy-driven convection of a viscoelastic fluid saturated in an open-top porous square box is studied based on a modified Darcy's law. The results are compared with those for a Newtonian fluid under the same boundary conditions and those for the viscoelastic fluid under a closed-top boundary. In particular, the critical Darcy-Rayleigh number Ra for onset of convection is determined first by using the linear stability theory. Then the effects of the relaxation time and the retardation time of the viscoelastic fluid on the heat transfer rate and the flow pattern are investigated numerically. The results reveal some interesting properties of thermal convection for the viscoelastic fluid. The relaxation time makes the fluid easier to destabilize while the retardation time tends to stabilize the fluid motion in the porous medium, and larger heat transfer rate can be achieved with larger value of the relaxation time and decreased retardation time. Furthermore, larger relaxation time facilitates earlier bifurcation of the flow pattern as Ra increases, but bifurcation can be postponed with increased retardation time. For larger ratio of relaxation time over retardation time, the flow pattern is more complicated and the frequency of flow oscillation also increases. Finally, large ratio of relaxation time over retardation time can make the open-top boundary impermeable due to the viscoelastic effect on the fluid. (C) 2009 Elsevier B.V. All rights reserved.; Mechanics; SCI(E); 9; ARTICLE; 5-6; 203-211; 165
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/244686]
专题	工学院
推荐引用方式 GB/T 7714	Niu, Jun,Fu, Ceji,Tan, Wenchang. Thermal convection of a viscoelastic fluid in an open-top porous layer heated from below[J]. 非牛顿流体力学杂志,2010.
APA	Niu, Jun,Fu, Ceji,&Tan, Wenchang.(2010).Thermal convection of a viscoelastic fluid in an open-top porous layer heated from below.非牛顿流体力学杂志.
MLA	Niu, Jun,et al."Thermal convection of a viscoelastic fluid in an open-top porous layer heated from below".非牛顿流体力学杂志 (2010).