English  |  正體中文  |  简体中文  |  Items with full text/Total items : 54367/62174 (87%)
Visitors : 14184562      Online Users : 73
RC Version 6.0 © Powered By DSPACE, MIT. Enhanced by NTHU Library IR team.
Scope Tips:
  • please add "double quotation mark" for query phrases to get precise results
  • please goto advance search for comprehansive author search
  • Adv. Search
    HomeLoginUploadHelpAboutAdminister Goto mobile version

    Please use this identifier to cite or link to this item: http://nthur.lib.nthu.edu.tw/dspace/handle/987654321/81001

    Authors: SHU, F.H.;STEWART, G.R.
    教師: 徐遐生
    Date: 1985
    Publisher: Elsevier
    Relation: ICARUS, Elsevier, Volume 62, Issue 3, 1985, Pages 360-383
    Abstract: We use a Krook equation, modified to allow collisions to be inelastic, to describe the dynamics of a particulate disk. By a simple heuristic argument, we compute the effective collision rate in a disk of spherical particles with a power-law distribution of sizes. For Saturn's rings, the effective collision rate for momentum transport is substantially lower than that conventionally estimated on the basis of an observed optical depth at visual wavelengths. We then discuss how the vertically integrated set of moment equations may be closed without the need to discard the third-order moments at the outset; our formulation allows for the possibility of a bent disk. In the limit that the collision frequency is much larger than the orbit frequency, we recover the usual Navier-Stokes equations of viscous hydrodynamics for a thin disk, with an explicit expression for the shear viscosity. For an unperturbed disk, we can solve the krook equation directly, without any assumptions about the magnitude of the collision frequency. Our analytical results, for an unperturbed disk, are in good agreement with the treatments of Hämeen-Anttila, of Goldreich and Tremaine, and of Borderies, Goldreich, and Tremaine, using a Boltzmann description for a collection of identical spheres (assumed to be smooth so that the rotational and translational degrees of freedom do not couple). As a final application of the method, we generalize the formation to include the effects of gravitational scattering. This generalization is not crucial for many applications in planetary rings, but it may be important for the discussion of gas clouds in the disk of a spiral galaxy, and it is probably central to the accumulation of planets from smaller bodies in the primitive solar nebula.
    Relation Link: http://www.elsevier.com/wps/find/homepage.cws_home
    URI: http://nthur.lib.nthu.edu.tw/dspace/handle/987654321/81001
    Appears in Collections:[ 徐遐生 (2002-2006)] 期刊論文
    [物理系] 期刊論文

    Files in This Item:

    File SizeFormat


    SFX Query


    DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - Feedback