[mostanad]

Hello my friends,
I am using fvOption tool to force a desired mean velocity in my periodic domain. The domain needs to mimic an unbounded box, so it should have zero mean velocity at three directions. To this end, I am forcing the zero Ubar through meanVelocityForce in my fvOption file. However, the fvOption cannot get the exactly zero value. A solution can be a very small value like

Ubar= (1e-7 1e-7 1e-7)

So do you think whether it is a good solution? Does it force zero mean velocity in my domain? How about using multiple fvOption sources like:

Ubar=(1e-7 0 0)
Ubar=(0 1e-7 0)
Ubar=(0 0 1e-7)

Is this possible in OF to use multiple meanVelocityForce sources?
Thank you for your help.
Mo

[mostanad]

Is this equivalent to these fvOption source terms?

momentumSource1
{
    type            meanVelocityForce;
    active          on;
    selectionMode   all; 
        

        fields  (U);
        Ubar        (0 0 0.0000001); 
}


momentumSource2
{
    type            meanVelocityForce;
    active          on;
    selectionMode   all; 
        
        fields  (U);
        Ubar        (0 0.0000001 0); 
}


momentumSource3
{
    type            meanVelocityForce;
    active          on;
    selectionMode   all; 
        
        fields  (U);
        Ubar        ( 0.0000001 0 0); 
}