Pore water convection within carbonaceous chondrite parent bodies: Temperature-dependent viscosity and flow structure

	Pore water convection within carbonaceous chondrite parent bodies: Temperature-dependent viscosity and flow structure
	Zhang, K ; Liao, XH ; Schubert, G
刊名	PHYSICS OF FLUIDS
	2005-08-01
卷号	17 期号:8 页码:086602-1
英文摘要	Thermal convection of pore water within a permeable, internally heated spherical body is investigated. Account is taken of the strong temperature dependence of the viscosity of water. With application to hydrothermal circulation in carbonaceous chondrite parent bodies in mind, the variation of gravity with radius in the body is also accounted for. The critical Rayleigh number for the onset of hydrothermal convection in a spherical porous body is determined as a function of the central temperature. It is found that the basic motionless state always becomes unstable with respect to an infinitesimal disturbance characterized by spherical harmonic degree l=2. The order of the spherical harmonics m, and hence the three-dimensional structure of the convective flow, cannot be determined by the stability analysis because of the degeneracy of the linear solution. The three-dimensional structure of the convective flow is determined by removing the degeneracy through the nonlinear effect of the temperature-dependent water viscosity. Three different convection solutions are found. However, the three-dimensional structures of these solutions are exactly the same and axisymmetric after an appropriate rotational transformation. The stability criterion is most effectively viewed as a requirement that the product of permeability and square of planetesimal radius exceed a quantity mainly dependent on central temperature. In this way, the criterion applies to planetesimals independent of the specific identification of the short-lived radionuclide responsible for early heating or its concentration. Evaluation of the criterion in this form leads to the conclusion that hydrothermal convection is likely in carbonaceous chondrite parent bodies heated sufficiently to melt the ice and raise the water temperature by tens to a hundred degrees Celsius. Weakly nonlinear convection in the planetesimals has two regions of hot upwelling water providing significant volumes of hydrothermally altered rock. (c) 2005 American Institute of Physics.
WOS标题词	Science & Technology ; Technology ; Physical Sciences
类目[WOS]	Mechanics ; Physics, Fluids & Plasmas
研究领域[WOS]	Mechanics ; Physics
关键词[WOS]	THERMAL-CONVECTION ; SPHERICAL-SHELL ; PLANETS ; FLUID
收录类别	SCI
语种	英语
WOS记录号	WOS:000231392000035
内容类型	期刊论文
源URL	[http://119.78.226.72/handle/331011/19399]
专题	上海天文台_天文地球动力学研究中心
作者单位	1.Chinese Acad Sci, Shanghai Astron Observ, Shanghai 200030, Peoples R China 2.Univ Exeter, Sch Math Sci, Exeter, Devon, England 3.Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA 4.Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA
推荐引用方式 GB/T 7714	Zhang, K,Liao, XH,Schubert, G. Pore water convection within carbonaceous chondrite parent bodies: Temperature-dependent viscosity and flow structure[J]. PHYSICS OF FLUIDS,2005,17(8):086602-1.
APA	Zhang, K,Liao, XH,&Schubert, G.(2005).Pore water convection within carbonaceous chondrite parent bodies: Temperature-dependent viscosity and flow structure.PHYSICS OF FLUIDS,17(8),086602-1.
MLA	Zhang, K,et al."Pore water convection within carbonaceous chondrite parent bodies: Temperature-dependent viscosity and flow structure".PHYSICS OF FLUIDS 17.8(2005):086602-1.