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[Expressions - swak4foam] troubles for custom boundary condition

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Old   June 7, 2022, 11:49
Default [Expressions - swak4foam] troubles for custom boundary condition
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Eric Segalerba
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Hi everybody,


I'm trying to implement a time dependent boundary condition.
I'm using Expressions that should be close to swak4foam but I can't really figure out how is the synthax.


This is the boundary condition I wrote

Code:
    

throat
{
     type            flowRateOutletVelocity;
     volumetricFlowRate    uniform -2.67e-04;
    
     type            exprFixedValue;

     variables
     (
         "CPI = 0.01"
         "p_throat{throat} = weightAverage(p.t())"
     );
    
     valueExpr
     #{
         CPI / p_throat
     #};

     value uniform (0 0 0);
 }
My doubts are the following:
1. surely I wrote in the wrong way the type but I can't figure out how to code a boundary condition which computes the flowrate
2. how can I make the code read the patch pressure runtime? Is .t sufficient?




Thank you in advance!
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Old   June 14, 2022, 10:07
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Mark Olesen
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I haven't checked much (or anything) of what you are actually doing, but you should note that for a flowRateOutletVelocity boundary condition, the "massFlowRate" or "volumetricFlowRate" is already a Function1, which means that you can also specify an expression for that.


I don't see a good reason why you would instead want to re-implement things using an exprFixedValue - IMO It makes more sense to leverage the existing boundary condition.
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