[bingchuan]

Dear foamer,

The manual says that the functionobjects add can be used to " Add a list of fields."

At the same time, the code gives an example as

Ttot {    
 type            add;    
 libs            ("libfieldFunctionObjects.so");    
 fields          (T Tdelta);    
 result          Ttot;    
 executeControl  writeTime;    
 writeControl    writeTime; 
}

But, it is still confusing for me. Can anyone give me more details about when to use it and how to use it. It seems that no such an example in the tutorials.

Bests.

Bingchuan

[einstein_zee]

Originally Posted by bingchuan

Dear foamer,

The manual says that the functionobjects add can be used to " Add a list of fields."

At the same time, the code gives an example as

Ttot {    
 type            add;    
 libs            ("libfieldFunctionObjects.so");    
 fields          (T Tdelta);    
 result          Ttot;    
 executeControl  writeTime;    
 writeControl    writeTime; 
}

But, it is still confusing for me. Can anyone give me more details about when to use it and how to use it. It seems that no such an example in the tutorials.

Bests.

Bingchuan

Hi there,

I think you forgot to read the next line which states "The operation can be applied to any volume or surface fields generating a volume or surface scalar field." I think this is quite clear about what this class does.

[bingchuan]

Dear Hosein,

Thank you for your reply.
In fact, I have read "The operation can be applied to any volume or surface fields generating a volume or surface scalar field " before. Since I am new with OF, it is still confusing for me.

I was wondering:
1) Does it have the same efficacy with the VolVectorField or VolScalarField in the creatFields.H?
2) If I created a field by the functionobject add, say a field XX which is related to the temperature. I think the calculation expression of XX should defined in the code. Where should I define the calculation expression of XX ?

So, could you please give me more details, such as sharing an example? Many Thanks.

Bests,
Bingchuan

[einstein_zee]

Hey there,

I think you mixed up some things with each other. To see what function objects do in general you might refer to this page "https://cfd.direct/openfoam/user-guide/v3-function-objects/".

Originally Posted by bingchuan

1) Does it have the same efficacy with the VolVectorField or VolScalarField in the creatFields.H?

volVectorField and volScalarField are just variable types in OF. And this has nothing to do with the function objects.

Originally Posted by bingchuan

2) If I created a field by the functionobject add, say a field XX which is related to the temperature. I think the calculation expression of XX should defined in the code. Where should I define the calculation expression of XX ?

Going back to our function object "add", this will add two or more scalar fields with each other. So this means you need to have a volScalarField (exp. temperature as it is stated in the example) defined either on a volume region or a surface one, to add them. The calculation that you referred, here is addition.

[bingchuan]

Dear Hosein,

I got it
The add function object is just to create a new field which is a sum of a few existing variables. I got it mixed up with registering a new field.
Thanks.

Bests,
Bingchuan

[Himanshu_Shrivastava]

Originally Posted by bingchuan

Dear Hosein,

I got it
The add function object is just to create a new field which is a sum of a few existing variables. I got it mixed up with registering a new field.
Thanks.

Bests,
Bingchuan

Hii, Can you post an example for this add function...

[HPE]

Hope this helps: https://www.openfoam.com/documentati...field-add.html

[Himanshu_Shrivastava]

Originally Posted by HPE

Hope this helps: https://www.openfoam.com/documentati...field-add.html

Hello Herpes,
Thank you for the quick reply.
I have seen that page but as I am new to oF and currently in learning phase, I have some doubts and was not able to understand clearly from that page.
Hence, I asked for an example to understand better.

If you allow, Can I asked few question regarding function object. I swear those are easy doubts but not for me

[HPE]

Hi,

A minimal example might be, say you want to add two fields of the same size and dimensions, X and Y:

add1
{
    type            add;
    libs            (fieldFunctionObjects);
    fields          (X Y);
}

You need to put the above inside `system/controlDict` file under `functions` subdictionary. Just append the following to your `controlDict` file if there is no `functions` subdictionary exists:

functions
{
    add1
    {
        type            add;
        libs            (fieldFunctionObjects);
        fields          (X Y);
    }
}

[Himanshu_Shrivastava]

Originally Posted by HPE

Hi,

A minimal example might be, say you want to add two fields of the same size and dimensions, X and Y:

add1
{
    type            add;
    libs            (fieldFunctionObjects);
    fields          (X Y);
}

You need to put the above inside `system/controlDict` file under `functions` subdictionary. Just append the following to your `controlDict` file if there is no `functions` subdictionary exists:

functions
{
    add1
    {
        type            add;
        libs            (fieldFunctionObjects);
        fields          (X Y);
    }
}

Hello Herpes,

Thank you for the example. I just read many post last night and many of doubts were solved.

Thanks!