[AlmostSurelyRob]

Dear Foamers,

I am seeking some advice on interFoam, pressure reference cells and cyclic boundaries conditions. I am trying to modify interFoam to run cyclic boundary conditions in a similar manner to channelFoam and then apply this model to simulate stratified flow in a pipeline.

I set up pipeline geometry, I put cyclic patches, I write velocity and pressure corrections to account for specified flow rates for each of the two phases.

When I was preparing my case I removed all pressure boundaries so eventually the only patches I have are wall and cyclic. interFoam would protest when I run it so I had to add

pRefCell 0
pRefValue 0

to system/fvSolution. My simulations seem to converge but after several hundred iterations they begin to oscillate.

So I modified the code to output cell residuals for each quantity. The most exciting action happens at the interface between phases (expected!) and at pressure reference cell (surprising?). For some reason velocity residuals are always very high at pressure reference cell. Please have a look at the attachment.

It would be great if you had the time to lend me some assistance on this matter. I can send/attach some case files if think it necessary.