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Zaktatir January 13, 2010 04:26

some Questions twophase flow
 
I am trying to make numerical investigation of droplets breakup in stratified flows.

First of al, a model for this stratified flow shoul be set up: which model is then more convenient, i think the inhomogeneous because air and water don't share the same velocity field and secondly entrainment is expected.

My geometrie is rectangular duct with horizontal part elbow and sloped part.

The tubulence in stratified flows needs kind of damping and for the source terms i should add an expresision which depens on the gradient calculation of the gas volume fraction: it comes to overflow, the question is whether i need very fine to calculate the gradient because i am interested in URANS simulations with not so fine grid. This term, like diffusion, is there to sharpen the interface without the use of the homogeneous features.

Subsequently i need to know which kind of BC i need because i have an elevated geometry:
0-Level: horizontal: Air inlet and Water outlet
h-Level: Outlet for a predicted two phase outflow + separate Water inlet. (called the ansys support talked about pressurized outlet the problem is i have nothing about the water level at the outlet)

i can attach a picture of this

thanks a lot


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