### Mixing chamber - 2 inlets same medium , 1 outlet

Posted:

**Mon Jun 24, 2019 10:32 am**Dear all,

I tried to solve another example for get myself more familiar with the CFD topic. It is a quite simple structure of

a pipe with 2 inlets (round shaped) and 1 outlet. The medium is the same for both inlets. I did meshing with cfmesh

and surface refinement at the inlets and outlet.

I tried a steady and a transient run.

Both did not work with certain boundary condition at the outlet.

Error message was:

21.1: OpenFOAM fatal error: Continuity error cannot be removed by adjusting the outflow.

21.2: Simulation exited with error

It has something to do with the boundary condition "outflow" because with "pressure" as boundary condition at the outlet it did

at least start to run eventhough residuals are somewhere in the dimension of 10^-1 to 10^-2 which is quite too high I guess.

I have the following questions:

(1) What is the issue with the "outflow" boundary ?

(2) How can I bring down the residuals ? Finer mesh in whole 3D model ? Mesh refinement )? Other values for k and w ?

Thx a lot !

I tried to solve another example for get myself more familiar with the CFD topic. It is a quite simple structure of

a pipe with 2 inlets (round shaped) and 1 outlet. The medium is the same for both inlets. I did meshing with cfmesh

and surface refinement at the inlets and outlet.

I tried a steady and a transient run.

Both did not work with certain boundary condition at the outlet.

Error message was:

21.1: OpenFOAM fatal error: Continuity error cannot be removed by adjusting the outflow.

21.2: Simulation exited with error

It has something to do with the boundary condition "outflow" because with "pressure" as boundary condition at the outlet it did

at least start to run eventhough residuals are somewhere in the dimension of 10^-1 to 10^-2 which is quite too high I guess.

I have the following questions:

(1) What is the issue with the "outflow" boundary ?

(2) How can I bring down the residuals ? Finer mesh in whole 3D model ? Mesh refinement )? Other values for k and w ?

Thx a lot !