[callumso]

Hi folks,

I am investigating the effects of sound waves on the flow through an orifice. As a starting point, I need to set up a flow with certain pressure drop across the orifice.

The flow is fed from a plenum through the orifice into a pipe. I used total pressure, total temperature for the inlet of the plenum and fixed pressure at the outlet of the pipe. I tried rhoPimpleFoam, sonicFoam and rhoDensityFoam. Unfortunately all of them blew up and failed with the error of "floating point exception".

The flow is slow with around 30m/s at the orifice and 0.041 m/s at the plenum and 1.4m/s in the pipe. I tried different time steps from 0.002s down to 0.00001s. But none of these really worked eventually. So I believe this is not a problem related to CFL number.

I noticed one or two other threads on this forum about difficulties on orifice flows, but no real solution has been given. It seems the orifice flow is quite a challenge for OpenFoam?

Can anyone here kindly give me some hints on how to get through this? Thanks in advance.