[kjetil]

Dear foamers,

I have put up a relatively simple case using interFoam, based on the approach in damBreak and 2D nozzle tutorials. I use setFields to "place" a load of water inside a pipe, which then is supposed to flush through the S-shaped geometry, and out. However, the water does not seem to exit the pipe at all. I have the following BCs (using OF 1.7.x):

alpha0:

inlet
{
type inletOutlet;
inletValue uniform 0;
value uniform 0;
}
outlet
{
type inletOutlet;
inletValue uniform 0;
value uniform 0;
}

U:

inlet
{
type zeroGradient;
}

outlet {
type zeroGradient;
}

p_rgh:
inlet
{
type fixedValue;
value uniform 0;
}

outlet
{

type fixedValue;
value uniform -200;
}

[sega]

You force alpha0 to be zero all the time at the inlet an outlet.
I think a zeroGradient would be more appropriate - at least for the outlet.

[kjetil]

Are you sure about this? My perception of the inletOutlet "value", is that this is the initial value, and changes as the simulation proceeds. Though if this was a fixedValue type, I would agree...

[sega]

The inletOutlet

switches and between fixedValue and zeroGradient depending on direction of

(http://www.openfoam.com/docs/user/bo...hp#x24-1390293)

The value-entry will then correspond to the case of fixedValue.
But I'm not sure how this "switch" will work.
But there is some fixedValue involved in this may be the problem.

I think inletOutlet is better for velocity or pressure, not for alpha0.

[kjetil]

I do see your point. The tutorials for interFoam, however, all use inletOutlet for alpha0.