[broali]

Hi Foamers,

I want to calculate the weighted average of a field in openfoam 9, but I realised that as opposed to the other version (e.g. openfoam 6 https://cpp.openfoam.org/v6/classFoa...ieldValue.html), there is no option for weightedAverage in surfaceFieldValue
(https://cpp.openfoam.org/v9/classFoa...ieldValue.html).
Any suggestion how can I calculate it for OpenFoam9?

Cheers

[kakila]

Any news on this? weightedSum also disappeared from OpenFoam v10. It was the easiest way to compute flows of a given phase in interFoam.

I tried areaIntegrate and areaAverage, but not getting the desired result.
Here an example that aims at computing the flow of water across a surface

#include "include/caseParameters"

type surfaceFieldValue;
libs ("libfieldFunctionObjects.so");
writeFields no;

regionType patch;
name Outlet;

operation areaIntegrate;
fields (alpha.water);

The problem is that, that doesn't give the flow. The intended integrand would be of phi*alpha.water.
Before I could achieve this with weightedSum, using alpha.water as weighting field.

How to do this in OF10?

Update:
Looking at the docs here: https://cpp.openfoam.org/v10/classFo...e.html#details

I find that this seems to achieve the intended calculation

#include "include/caseParameters"

type surfaceFieldValue;
libs ("libfieldFunctionObjects.so");
writeFields no;

regionType patch;
name Inlet;

operation areaIntegrate;
fields (phi);
weightField alpha.water;

because the "weightField " is indeed processed.

[Krapf]

Weighted operations have been removed. Weighting for averages and sums is now triggered simply by the existence of the "weightField" or "weightFields" entry.

Source: https://github.com/OpenFOAM/OpenFOAM...b34102fff0c63f

[broali]

Thank you both for your help. Clear!

[zjy]

Originally Posted by kakila

Any news on this? weightedSum also disappeared from OpenFoam v10. It was the easiest way to compute flows of a given phase in interFoam.

I tried areaIntegrate and areaAverage, but not getting the desired result.
Here an example that aims at computing the flow of water across a surface



The problem is that, that doesn't give the flow. The intended integrand would be of phi*alpha.water.
Before I could achieve this with weightedSum, using alpha.water as weighting field.

How to do this in OF10?

Update:
Looking at the docs here: https://cpp.openfoam.org/v10/classFo...e.html#details

I find that this seems to achieve the intended calculation

because the "weightField " is indeed processed.

On of9, I hope to use the following code to calculate the flow on a certain plane in the two-phase flow dambreak,

surfaceFieldValue2
{
type surfaceFieldValue;
libs ("libfieldFunctionObjects.so");

log true;
writeControl writeTime;
writeFields true;

surfaceFormat none;
regionType faceZone;
name flowrate2;

operation sum;

weightField alpha.water;

fields (phi);
}

but the following error occurs：
[2] --> FOAM FATAL ERROR:
[2] surfaceFieldValue surfaceFieldValue1: faceZone(flowrate1):
Unable to process internal faces for volume field alpha.water
Do you know how to solve it

[JulioPieri]

Originally Posted by zjy

On of9, I hope to use the following code to calculate the flow on a certain plane in the two-phase flow dambreak,

surfaceFieldValue2
{
type surfaceFieldValue;
libs ("libfieldFunctionObjects.so");

log true;
writeControl writeTime;
writeFields true;

surfaceFormat none;
regionType faceZone;
name flowrate2;

operation sum;

weightField alpha.water;

fields (phi);
}

but the following error occurs：
[2] --> FOAM FATAL ERROR:
[2] surfaceFieldValue surfaceFieldValue1: faceZone(flowrate1):
Unable to process internal faces for volume field alpha.water
Do you know how to solve it

I know this is an old thread, but I believe the problem is related to the fact that alpha.water is not defined on faces. You have to first make cell/face fields available for each other, and then apply the surface field value

Check: faceZoneAverage function object does not work with field U,p etc.