[CIG-SHORT] Problem setting initial conditions
Charles Williams
willic3 at gmail.com
Sun Feb 9 12:30:58 PST 2014
Sorry for being slow to respond to this, Oliver. I haven’t gone through everything in detail, but one thing I noticed is that your boundary conditions on the external boundaries are different for the two problems, which means that you won’t be able to get the same stress/strain state for the two cases. One possible solution would be to leave one boundary free. I’m not sure if this will work or not, but it’s probably worth a shot.
Cheers,
Charles
On 8/02/2014, at 6:50 am, Oliver Boyd <olboyd at usgs.gov> wrote:
> Hi Brad,
> Attached are some figures illustrating what I mean. In step1Kin, I use
> Dirichlet boundary conditions on the domain edges and specified 100 cm of
> fault slip on the fault. This generates stresses and strains in the
> materials and tractions on the fault as depicted in the figure
> step1Kin.png. If I let this simulation run, the viscoelastic layer will
> relax. But I'd like to change the conditions on the fault surface. So as a
> first step, I wanted to transfer the stresses and strains to step2Kin and
> let them relax. In step2Kin, domain boundaries and fault surface initial
> displacement is zero. I am hoping to get step1Kin and step2Kin to show the
> same results after 200 years. But they don't. There is the expected
> relaxation in step1Kin, but there is no relaxation in step2Kin. When I
> first transferred just the stress through db_initial_stress and looked at
> the stresses, strains, and tractions, step2Kin_stressini.png, I figured I
> only needed to transfer over the strains to make it look like step1Kin and
> everything would proceed as expected. But I haven't figured out how to
> transfer the strains properly. When I attempt to transfer both the
> stresses and strains, They appear to be working against each other.
> (step2Kin_stress_strain_ini.png).
>
> Oliver
>
> On 2/6/14 4:45 PM, "Brad Aagaard" <baagaard at usgs.gov> wrote:
>
>> Oliver,
>>
>> For the db_initial_strain, you are correct in that the values in the
>> spatial database are strain-xx, etc.
>>
>> I don't know what you mean by "seeing the initial strain field being
>> set". You can ask for the "initial_strain" field to be written as one of
>> the cell info fields to check to make sure it is read in and matches
>> what you expect the spatial database to produce. It does look like we
>> may not be including the initial strain in the "total_strain" output
>> field. Is this what you mean by "not seeing the initial strain field
>> being set" or are you seeing the initial strain field not affecting the
>> solution in the way you expect?
>>
>> Brad
>>
>> On 02/03/2014 09:04 AM, Oliver Boyd wrote:
>>> Hi Brad,
>>> Thanks for your help. I had initially tried using db_initial_strain as
>>> well as several of other things. I did as you suggested below, but do
>>> not
>>> see the initial strain field being set after running step2Kin. Thanks
>>> for
>>> reminding me of the use of --component.help. I was trying to figure out
>>> what variables I needed to set in db_initial_strain. Based on the
>>> manual I
>>> thought it was strain-xx Š, but I wasn't sure. I thought I might be able
>>> to get to it with help-properties, but I still haven't figured that out.
>>> In any case, I'm still doing something wrong.
>>>
>>> Thanks again for your help,
>>> Oliver
>>>
>>> On 2/2/14 11:07 AM, "Brad Aagaard" <baagaard at usgs.gov> wrote:
>>>
>>>> Oliver,
>>>>
>>>> There are separate spatial databases for initial stress and initial
>>>> strain.
>>>>
>>>> [pylithapp.timedependent.materials.upper_crust]
>>>> db_initial_stress = spatialdata.spatialdb.SimpleDB
>>>> db_initial_stress.label = Initial stress in upper crust
>>>> db_initial_stress.iohandler.filename =
>>>> spatialdb/afterslip_stress_uppercrust.spatialdb
>>>> db_initial_stress.query_type = nearest
>>>>
>>>> # ADD db_initial_strain
>>>> db_initial_strain = spatialdata.spatialdb.SimpleDB
>>>> db_initial_strain.label = Initial strain in upper crust
>>>> db_initial_strain.iohandler.filename =
>>>> spatialdb/afterslip_strain_uppercrust.spatialdb
>>>> db_initial_strain.query_type = nearest
>>>>
>>>> Remember you can use pylith --COMPONENT.help and
>>>> --COMPONENT.help-properties and --COMPONENT.help-components to
>>>> interrogate what properties and components are available. In this case
>>>> COMPONENT would be
>>>> timedependent.materials.upper_crust.
>>>>
>>>> pylith step1Kin.cfg
>>>> --timedependent.materials.upper_crust.help-components
>>>> facilities of 'elasticisotropic3d':
>>>> db_initial_state=<component name>: Database for initial state
>>>> variables.
>>>> current value: 'nullcomponent', from {default}
>>>> configurable as: nullcomponent, db_initial_state
>>>> db_initial_strain=<component name>: Database for initial strain.
>>>> current value: 'nullcomponent', from {default}
>>>> configurable as: nullcomponent, db_initial_strain
>>>> db_initial_stress=<component name>: Database for initial stress.
>>>> current value: 'nullcomponent', from {default}
>>>> configurable as: nullcomponent, db_initial_stress
>>>> db_properties=<component name>: Database for physical property
>>>> parameters.
>>>> current value: 'simpledb', from {default}
>>>> configurable as: simpledb, db_properties
>>>> output=<component name>: Output manager for elastic material
>>>> information.
>>>> current value: 'outputmatelastic', from {default}
>>>> configurable as: outputmatelastic, output
>>>> perf_logger=<component name>: Performance and memory logging.
>>>> current value: 'memory_logger', from {default}
>>>> configurable as: memory_logger, perf_logger
>>>> quadrature=<component name>: Quadrature object for numerical
>>>> integration.
>>>> current value: 'quadrature', from {default}
>>>> configurable as: quadrature
>>>>
>>>> Brad
>>>>
>>>> On 1/31/14 11:26 AM, Oliver Boyd wrote:
>>>>> Hello,
>>>>> I'm trying to generate a set of initial conditions in one problem and
>>>>> then use them in another. The first problem calculates the stress
>>>>> changes due to an earthquake. Currently, the second problem only looks
>>>>> at the viscoelastic response (which of course can be done in the first
>>>>> problem). Once I get the viscoelastic response in the second problem
>>>>> to
>>>>> equal the first (if I let the first progress through time), I will
>>>>> change the fault interface model, but this is not yet implemented.
>>>>>
>>>>> I'm able to transfer over the initial stress through db_initial_stress
>>>>> but I don't know how to transfer the initial strain. I've tried
>>>>> putting
>>>>> the initial strain in the db_initial_stress.iohandler.filename file
>>>>> with
>>>>> the components given by p71 of the manual, but they don't appear to
>>>>> have
>>>>> an effect when I run the simulation. Attached are the files needed for
>>>>> the simulation.
>>>>>
>>>>> Thanks for your assistance,
>>>>> Oliver
>>>>>
>>>>> Flow
>>>>> pylith step1Kin.cfg
>>>>> python afterslip_initial_parms.py
>>>>> pylith step2Kin.cfg
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> CIG-SHORT mailing list
>>>>> CIG-SHORT at geodynamics.org
>>>>> http://geodynamics.org/cgi-bin/mailman/listinfo/cig-short
>>>>>
>>>>
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>
> <step2Kin_stress_strain_ini.png><step2Kin_stressini.png><step1Kin.png><step2Kin.cfg><step1Kin.cfg>_______________________________________________
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Charles A. Williams
Scientist
GNS Science
1 Fairway Drive, Avalon
PO Box 30368
Lower Hutt 5040
New Zealand
ph (office): 0064-4570-4566
fax (office): 0064-4570-4600
C.Williams at gns.cri.nz
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