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Warning running groovyBC: "min ... max ... differ, I will use the average"

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Old   September 15, 2015, 22:39
Default Warning running groovyBC: "min ... max ... differ, I will use the average"
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Mick McGill
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Hi everyone,

I'm running a case where heat loss is calculated through the walls using a groovyBC gradientExpression. The code used for this in 0/T is:

Code:
leftWall
    {
        type            groovyBC;
        refValue        uniform 1680;
        refGradient     uniform 0;
        valueFraction   uniform 1;
        value           uniform 1680;
        valueExpression "0";
        gradientExpression "(Toutlet > 1680) ? ((-(h*A*(Toutlet-T_inf)+esp*A*sig*(pow(Toutlet,4)-pow(T_surr,4))))/kl) : ((-(h*A*(Toutlet-T_inf)+esp*A*sig*(pow(Toutlet,4)-pow(T_surr,4))))/ks) ";
        fractionExpression "0";
        evaluateDuringConstruction 0;
        variables       
9
(
"h=10.0;"
"A=0.00845561879;"
"T_inf=297.0;"
"T_surr=297.0;"
"esp=0.3;"
"sig=5.67e-8;"
"ks=20;"
"kl=60;"
"Toutlet{leftWall}=oldTime(T);"
)
;
        timelines       (
);
        lookuptables    (
);
    }
The case runs and the results are similar to what is expected, however the warning:

Code:
--> FOAM Warning : 
    From function ExpressionResult::getUniformInternal(const label size,bool noWarn)
    in file ExpressionResult/ExpressionResultI.H at line 350
    The minimum value 1674.98 and the maximum 1675.21 differ. I will use the average 1675.14
--> FOAM Warning : 
    From function ExpressionResult::getUniformInternal(const label size,bool noWarn)
    in file ExpressionResult/ExpressionResultI.H at line 350
    The minimum value 1682.8 and the maximum 1959.02 differ. I will use the average 1838.05
--> FOAM Warning : 
    From function ExpressionResult::getUniformInternal(const label size,bool noWarn)
    in file ExpressionResult/ExpressionResultI.H at line 350
    The minimum value 1682.8 and the maximum 1957.31 differ. I will use the average 1838.05
Any advice would be greatly appreciated. I have a feeling that it may be because of how Toutlet{backwall} is specified, it is looking to take data from another patch which would be required to be a uniform field, however I am not sure.

Thanks,

Mick.
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Old   September 21, 2015, 10:52
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Mick McGill
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For anyone that comes accross this wanting to know what the warning was for, the use of the {} bracketed terms eg
Code:
Toutlet{leftWall}=oldTime(T)
Indicates to the solver that the boundary condition is being taken from a remote patch, which must have a uniform condition, hence the average temperature is taken. To have it instead calculate the boundary condition on a cell by cell basis, simple remove the {} term (in this case {leftWall} ).
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Old   July 28, 2017, 12:21
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Colli, Alejandro
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Quote:
Originally Posted by mick223 View Post
For anyone that comes accross this wanting to know what the warning was for, the use of the {} bracketed terms eg
Code:
Toutlet{leftWall}=oldTime(T)
Indicates to the solver that the boundary condition is being taken from a remote patch, which must have a uniform condition, hence the average temperature is taken. To have it instead calculate the boundary condition on a cell by cell basis, simple remove the {} term (in this case {leftWall} ).
But, if u remove that term, how u get access to the remote patch?
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Old   July 30, 2017, 08:55
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Bernhard Gschaider
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Quote:
Originally Posted by ancolli View Post
But, if u remove that term, how u get access to the remote patch?
General interpolation from one patch to another is tricky and would need additional specifications (especially if the patches are not conformal) so swak4Foam doesn't bother to even try and only accepts uniform patches. If the patches are coupled or mapped the functions neighbourField(T) or mapped(T) give the corresponding values. But oldTime won't work in these cases
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