Author Topic: Newtons method failed to converge in 100 iterations.  (Read 3479 times)

Offline pitney1

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Newtons method failed to converge in 100 iterations.
« on: May 11, 2012, 10:32:40 PM »
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The Solver crahes with no helpful error, but does give the following warning on the iteration before failure: +--------------------------------------------------------------------+ | ****** Notice ****** | | Newtons method failed to converge in 100 iterations. This | | occurred while computing the following variable: | | | | Variable Name : Total Temperature | | Location Name : sparks | | Mesh location : VERTICES | | Mesh entity : | | Last 3 Changes : 1.26616E+03 1.26326E+03 1.26767E+03 | | Tolerance : 1.0000E-02 | | | | The Newton iteration was diverging. The solver will continue | | with the variable field as it was on the final iteration. If | | this situation continues you might try decreasing the Netwon | | iteration under relaxation factor. This can be changed by | | setting one of the following parameters: | | | | Temperature : "Constitutive Relation Under Relaxation" | | Pressure : "Newton Pressure Under Relaxation" | | | | for your mixture using the definition file editor. | +--------------------------------------------------------------------+

Offline william

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Re: Newtons method failed to converge in 100 iterations.
« Reply #1 on: May 11, 2012, 10:33:12 PM »
Check the CCL for your combustion calculation. For each domain, the combustion model section might read as follows:

In dom1:

FLUID MODELS:
COMBUSTION MODEL:
Eddy Dissipation Model Coefficient B = 0.5
Extinction Temperature = 5000[K]*(1-fcomb1)+700[K]*fcomb1
Option = Eddy Dissipation
END

In dom2:

FLUID MODELS:
COMBUSTION MODEL:
Eddy Dissipation Model Coefficient B = 0.5
Extinction Temperature = 5000[K]*(1-fcomb2)+700[K]*fcomb2
Option = Eddy Dissipation
END

In dom3:

FLUID MODELS:COMBUSTION MODEL:
Eddy Dissipation Model Coefficient B = 0.5
Extinction Temperature = 5000[K]*(1-fcomb3)+700[K]*fcomb3
Option = Eddy Dissipation
END

Finally, in sparks:

FLUID MODELS:
COMBUSTION MODEL:
Eddy Dissipation Model Coefficient B = 0.5
Extinction Temperature = 5000[K]*(1-fcombs)+700[K]*fcombs
Option = Eddy Dissipation
END

The expression fcombs = fcomb1 + fcomb2 + fcomb3 should be added to the CEL section.