一般问题每个格子尺度多大啊？10^-4m可以吗？

3.14布

初学者求解答！

luo@odu.edu

You should consider the grid Reynolds number for direct numerical simulation (DNS), i.e.,

Re* = \delta x U / \nu

where \delta x, U, \nu are grid spacing size, the characteristic velocity, and the viscosity, respectively. Re* should be small (less than 1.0??). Looking at the grid size in absolute, physical unit in isolation is not a good practice. That is why the Navier-Stokes equation has to be nondimensionalized, to include the Reynolds number Re.

-- L.-S. Luo

3.14布

可是如果研究粘性很大的液体导热问题时，液体几乎是静止的，Re接近于零啊，网格又该画多大合适呢

luo@odu.edu

If the problem involves heat transfer, then one must consider the Rayleigh number Ra, the grid spacing must be small enough to resolve the thermal boundary layer. See the following paper:

J. Wang, D.H. Wang, P. Lallemand, and L.-S. Luo.
Lattice Boltzmann simulations of thermal convective flows in two dimensions.
Computers and Mathematics with Applications 65(2):262-286 (January 2013)

which you can download from my website (http://www.lions.odu.edu/~lluo).

-- LSL

[ 本帖最后由 luo@odu.edu 于 2014-4-21 01:36 编辑 ]

3.14布

谢谢您