[dhaya400]

Hi..

Why outflow BC is not recommended for multiphase flow mixture model ? But I came across the below tutorial from Ansys which uses outflow BC for mixture model.

Link : https://mae.iith.ac.in/ansys/files/s..._tut/tut20.pdf

Please clarify the doubt.

[LuckyTran]

An individual outflow BC is generally not recommend for a lot of things once you leave incompressible land because it doesn't provide enough constraints to solve the N-S equations.

In this tutorial, a velocity inlet is being used. Nothing fixes the overall massflow in this problem and the outflow BC is used to just split the volumetric flowrate over the two outlets.

[dhaya400]

Originally Posted by LuckyTran

An individual outflow BC is generally not recommend for a lot of things once you leave incompressible land because it doesn't provide enough constraints to solve the N-S equations.

In this tutorial, a velocity inlet is being used. Nothing fixes the overall massflow in this problem and the outflow BC is used to just split the volumetric flowrate over the two outlets.

Thank you for your reply.

If the CFD problem is incompressible multiphase flow simulation and I know only the massflow at the outlets.

Then shall I use outflow boundary condition?