[enass massoud]

Hi.
i am trying to develop UDF to calculate the bubble velocity for certain number of time steps for 2 phase gas-liquid slug flow in vertical pipe, and then calculate new inlet velocity and check if convergence is established between initial and calculated velocity. If convergence is established then stop solution and hence calculated velocity is the terminal bubble velocity. If not, then reassign new calculated velocity to boundary condition and repeat process until convergence is established. Any help please???