[bijan darbari]

Dear Foamers

In many OpenFoam codes we can see some imported constant scalars.
For example look at lines 163-170 of:

src/lagrangian/turbulence/submodels/Thermodynamic/ParticleForces/BrownianMotion/BrownianMotionForce.C

Foam::forceSuSp Foam::BrownianMotionForce<CloudType>::calcCoupled
(
    const typename CloudType::parcelType& p,
    const scalar dt,
    const scalar mass,
    const scalar Re,
    const scalar muc
) const

Due to above lines, we can see that "dt" , "mass" , "Re" and "muc" have been imported to this code and all these scalars have predefined values.

Now, I want to know where the scalar "dt" defined and calculated before it have been imported to these code??