[CIG-SHORT] attenuation in a dynamic model?

[Eunseo Choi]

Thanks for the confirmation, Brad!

I'll try a smaller time step but don't understand why it would work.
The time step I used was a stable one for the dynamic problem, ~0.01 sec,
which was already much smaller than relaxation times I tried, ~1 sec to ~1
year.

Eunseo


On Thu, Aug 6, 2015 at 1:03 PM, Brad Aagaard <baagaard at usgs.gov> wrote:

> Eunseo,
>
> Attenuation for dynamic models is not yet implemented. This has been on
> the TODO list for a while but many other features have been a higher
> priority.
>
> If you try to use a viscoelastic model with a high viscosity, then you
> will likely need to reduce the time step. I am guessing that the
> instability you see is starting at a cell that is slightly more distorted
> so it has a smaller stable time step.
>
> Regards,
> Brad
>
>
> On 08/06/2015 09:17 AM, Eunseo Choi (echoi2) wrote:
>
>> Can PyLith have attenuation in an explicit dynamic problem?
>>
>> I couldn't find how to do this anywhere in the v.2.1.0 manual.
>>
>>
>> So, I first tried MaxwellIsotropic3D expecting the relaxation effect
>> to do the job but even with a very high viscosity, an instability
>> kicks in around the boundary where a time-dependent traction BC is
>> applied. Maybe this material model works only in static or
>> quasi-static problems? Or is it more likely to be a mistake in my
>> problem setup?
>>
>>
>> I also read in PyLith's TO-DO list that the plan is to use the
>> generalized Maxwell model for attenuation. Is this the material model
>> I was supposed to use? Is it working in v.2.1.0 but just not being
>> discussed in the manual?
>>
>>
>> Thanks,
>>
>> Eunseo
>>
>>
>>
>>
>>
>> _______________________________________________ CIG-SHORT mailing
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>>
>>
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