On 11/27/2017 01:16 PM, Jane Lee wrote:
I'm trying to apply some partial boundary conditions to the step-22
stokes problem. I can't seem to find much further help on this and when
I try and implement it, it solves but solution is clearly unstable/blows
up.
I am trying the basics before i impose inhomogeneous quantities, and
using no normal flux on the boundary, which constrains one component,
and then allow no tangential stresses either, which should constrain the
other two. Can anyone spot where I'm going wrong?
I don't think you can do it that way -- this would constrain the normal
component in terms of the tangential components, and then somehow try to
find a coordinate system in which to constrain the tangential
components, but I can completely see how this leads to circular
dependencies and all sorts of other weirdness. If you want a zero
boundary condition, then just impose zero for all components.
I'll add that *theoretically* things should work this way -- you are
constraining all components. But *algorithmically*, I don't think that's
a useful approach.
Best
W.
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Wolfgang Bangerth email: bange...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/
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