Forchheimer nonlinear flow model

Dear colleagues, the syntax:

$FLOWLINEARITY
4 1.17 2.5

in the .mmp file is correctly acknowledged by ogs as firing the Forchheimer nonlinear flow model. The response of ogs is:

MMPRead … ->Forchheimer nonlinear flow with given a1, a2

However, only the first parameter (the 1.17 here) is used, and we suspect that it is the Izbash model that is applied, not the Forchheimer model. This behaviour is common in all recent versions of OpenGeosys (at least from 5.4 onwards). Does anybody know the reason for this behaviour? Is there a way to apply the Forchheimer model with given a1 and a2?

Best regards,
John

Dear John,

As far as I checked the code, both parameters are used in the flow linearity model 4.
OGS calculates relative permeability of the model as

        k_rel = 1.0/(a1 + a2*|v|)

Do you have $LOCAL_PICARD1 keyword in your *.num file as below? Without the keyword, the model doesn't work correctly.

  $LOCAL_PICARD1
   200 1e-10

Regards,
Nori

···

On 03/18/2015 11:00 PM, John N.E. Papaspyros wrote:

Dear colleagues, the syntax:

  $FLOWLINEARITY
   4 1.17 2.5

in the .mmp file is correctly acknowledged by ogs as firing the
Forchheimer nonlinear flow model. The response of ogs is:

MMPRead ... ->Forchheimer nonlinear flow with given a1, a2

However, only the first parameter (the 1.17 here) is used, and we
suspect that it is the Izbash model that is applied, not the Forchheimer
model. This behaviour is common in all recent versions of OpenGeosys (at
least from 5.4 onwards). Does anybody know the reason for this
behaviour? Is there a way to apply the Forchheimer model with given a1
and a2?

Best regards,
John

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Norihiro Watanabe, Dr.-Ing.
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Helmholtz-Zentrum für Umweltforschung GmbH - UFZ
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Dear Nori, you are my hero! I can’t thank you enough for your help!

All the best,
John

Τη Πέμπτη, 19 Μαρτίου 2015 - 12:00:29 π.μ. UTC+2, ο χρήστης John N.E. Papaspyros έγραψε:

···

Dear colleagues, the syntax:

$FLOWLINEARITY
4 1.17 2.5

in the .mmp file is correctly acknowledged by ogs as firing the Forchheimer nonlinear flow model. The response of ogs is:

MMPRead … ->Forchheimer nonlinear flow with given a1, a2

However, only the first parameter (the 1.17 here) is used, and we suspect that it is the Izbash model that is applied, not the Forchheimer model. This behaviour is common in all recent versions of OpenGeosys (at least from 5.4 onwards). Does anybody know the reason for this behaviour? Is there a way to apply the Forchheimer model with given a1 and a2?

Best regards,
John