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-   -   How to find error in runing earth (https://www.cfd-online.com/Forums/phoenics/51604-how-find-error-runing-earth.html)

John May 16, 2003 23:55

How to find error in runing earth
 
Hi:

I compile a Q1 file and run earth, It fails to run after several steps. Where can I find the reason? I open the 'result' and find the information as follows

--- INTEGRATION OF EQUATIONS BEGINS ---

absbk1 = 3.530345E-02 absbk2 = 4.293048E-02

block-correction switched off absolute pressure .le. 0. run aborted l0p = 491826 i = 62 p =-2.085495E+05 press0 = 1.000000E+05

namsub= PRFILE; namfun= NONE set varmin(p1)) to: - 0.5*PRESS0, say, for a near-atmospheric-pressure flow isweep = 4 izstep = 29 ixy slab= 62 I do not know how can set the limit about pressure?

Thanks

John Ludwig, CHAM May 19, 2003 05:14

Re: How to find error in runing earth
 
For some reason the pressure is going to excessively negative values. To put a minimum value on pressure, you can either edit the Q1 file, and in the Group 18 section add the line:

VARMIN(P1)=-0.5*PRESS0

as at the bottom of the result file, or in the VR-Editor, you can open the Main menu, then the Numerics panel. Click on 'Limits on Variables'. From there you can set the minimum and maximum values for all the solved and stored variables.

However, the pressure going crazy is usually a symptom of some other problem - it is rarely the cause of the problem itself. It may be that there are incompatible or missing boundary conditions or other settings.

If you cannot figure it out, and you have a valid support agreement, you can e-mail your Q1 to support@cham.co.uk, and they will sort it out for you.


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