[Cluap]

Hi everybody,

I'm using OpenFOAM 1.7 with dieselSpray, in order to model gasoline droplets in a turbulent air flow with an Euler approach for the carrier phase and a lagrangian appproach for the droplets.

When I look at the lagrangian equation in parcel.C, I see :

U() = (U() + (timeRatio*Ucorr)+ gcorr*dt)/(1.0 + timeRatio); (Eq 1)

where U() is the droplet velocity, Ucoor the velocity of the gas seen by the droplet and timeRatio=dt/tauMomentum whith tauMomentum the droplet relaxation time.

But this looks very different from any classical lagrangian equation which should be something like :

dUp/dt = (Ug - Up)/Tp + g (Eq 2)

where Up is the velocity of the droplet, Ug the velocity of the gas seen by the droplet ant Tp the droplet relaxation time.

Discretized it should be something like :

U() = (1 - timeRatio)*U() + (timeRatio*Ucorr) + gcorr*dt (Eq 3)


So why does OpenFoam use Eq 1 instead of Eq 3 ?

Any help would be very appreciated.

Thank you.