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adaptive time stepping

#1

Hi all,
My original time is

#TIME_STEPPING

$PCS_TYPE

OVERLAND_FLOW

$TIME_END

243040

$TIME_START

0

$TIME_STEPS

43200 20

#TIME_STEPPING

$PCS_TYPE

RICHARDS_FLOW

$TIME_END

243040

$TIME_START

0

$TIME_STEPS

43200 20

When I changed the TIME_STEPS to larger value such as 3600, the code rejects the solution. So I want to move to adaptive time stepping.

I found there is an example of TIME_CONTROL SELF_ADAPTIVE in the example: abdul

However, I did not understand the meaning of the parameters. When I use the adaptive time stepping:

#TIME_STEPPING

$PCS_TYPE

OVERLAND_FLOW

$TIME_CONTROL

SELF_ADAPTIVE

4 1.7

10 0.7

MAX_TIME_STEP

100

MINISH

2

It only gave me two results at T=0 and T= 1e308

Do you know how to set up reasonable adaptive parameters for my case?

Thanks,

Xuan

#2

Hi,

We recently updated TIME_CONTROL SELF_ADAPTIVE while keeping compatibility with older versions. You can find updated description of the method in the latest release note:

https://svn.ufz.de/ogs/wiki/ReleaseNotes

If you don't have an account to access the above link yet, please contact to thomas.kalbacher@ufz.de to make it.

Best,
Nori

···

On 01/12/2015 01:08 PM, Xuan Yu wrote:

Hi all,
My original time is
#TIME_STEPPING
$PCS_TYPE
OVERLAND_FLOW
$TIME_END
243040
$TIME_START
0
$TIME_STEPS
43200 20
#TIME_STEPPING
$PCS_TYPE
RICHARDS_FLOW
$TIME_END
243040
$TIME_START
0
$TIME_STEPS
43200 20
When I changed the TIME_STEPS to larger value such as 3600, the code
rejects the solution. So I want to move to adaptive time stepping.
I found there is an example of TIME_CONTROL SELF_ADAPTIVE in the
example: abdul
However, I did not understand the meaning of the parameters. When I use
the adaptive time stepping:

#TIME_STEPPING

  $PCS_TYPE

   OVERLAND_FLOW

  $TIME_CONTROL

    SELF_ADAPTIVE

    4 1.7

    10 0.7

  MAX_TIME_STEP

    100

  MINISH

   2

It only gave me two results at T=0 and T= 1e308

Do you know how to set up reasonable adaptive parameters for my case?

Thanks,

Xuan

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Department of Environmental Informatics (ENVINF)
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#3

Hi

With the svn shutting down last year, is it possible to access documentation on time control elsewhere?

Regards
Swamini

#4

Hey,

You’ll find the keyword documentation here and some infos on adaptive time stepping here.

Example files from benchmarks are e.g.:

1d_ho.tim
h_us_drainage.tim
h_us_line_celia.tim
h_us_line_Forsyth.tim
h_us_line_Halm.tim
h_us_line_Warrick.tim
h_us_quad.tim
h_us_tri_freebc.tim
…

Best,
Timo

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