[CIG-SHORT] Dirichlet and Neumann boundary conditions simultaneously for different degrees of freedom of the same edge

[Matthew Knepley]

On Tue, Jan 3, 2017 at 3:47 AM, Ekaterina Yevgenyevna Bolotskaya <
bolee at mit.edu> wrote:

> Dear Developers,
>
> I've started working with pylith only recently.
>
> I'm currently working on a 2D simulation where I need to initially
> compress a 2D block in both directions and then have y-displacement fixed
> for vertical boundaries. Thus, I need to apply Dirichlet and Neumann
> boundary conditions simultaneously for different degrees of freedom of
> the same edge.
>

We need to clarify exactly what you want to do:

  a) First, compress a block in both x- and y-. I assume that you mean
apply a given traction to the surface. How long are you waiting for the
compression? Is this a steady state problem?

  b) Second, fix the y- displacement and remove the compressive forces, and
look at the rebound. Is this a time-dependent problem?


> Could you tell me if I can do that and how?
>

Note that applying both Dirichlet and Neumann conditions at the same time
for the elliptic problem in PyLith does not make mathematical sense.

  Thanks,

     Matt


> Thanks!
>
>
> Best regards,
> Ekaterina Bolotskaya
>
> PhD in Geophysics,
> Earth, Atmospheric and Planetary Science Department,
> Massachusetts Institute of Technology
> E-mail. bolee at mit.edu
> Mob. +1 (857) 284-2805 <%2B1%20%28857%29%20284-2805>
>          +7 (963) 995-36-33 <%2B7%20%28963%29%20995-36-33>
>
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