[nanavati]

Hello All,

I am confused about the usage and meaning of, Calculated BC.

in many OF Tutorials it has been used in 0/nut file for inlet and outlet.

Can anyone please throw some light on it.

Many Thanks.

[blacksquirrel]

Hello nanavati,

calculated means, that the property you are referring to is already fully defined by the other boundary conditions and properties you defined in the constant folder.

For example nu_t (or mu_t) is defined via k and epsilon by
nu_t= C * k^2/epsilon

So OpenFOAM can calculate the boundary conditions for nu_t via the ones you gave it for k and epsilon. You only specify the wall-function for nu_t.

Regards
Squirrel

[nanavati]

Many Thanks for the Detailed Explanation.

[tomf]

It means the values are calculated from the turbulence model and the values for k and epsilon (or omega) and not prescribed.

Regards,
Tom

[cleoo]

but how come it makes us specify a value?
by default it is just zero is that just like a place holder for when the value is calculated?

[blacksquirrel]

Hi cleoo,

You are right, the value for the calculated boundary patch field is just a place holder.

The description text of "calculatedFvPatchField.H" states, that the value entry is optional.

   myPatch
    {
        type            calculated;
        value           uniform (0 0 0);    // optional value entry
    }

Regards
Squirrel

[kk415]

Hello All,

I have a question. How is nut calculated in dyanmicKEqnModel. Is there any good description on dynamicKEqnModel?

Thanks

[guanjiang.chen]

Originally Posted by kk415

Hello All,

I have a question. How is nut calculated in dyanmicKEqnModel. Is there any good description on dynamicKEqnModel?

Thanks

Hi，

Do you have some problems in dynamickequation model? when I use it to calculate the flow through cylinder. I find that the value of nut will close to 0, and then the float point exception problem will happen.

Sincerely,
Guanjiang