[grjmell]

To check some funcitonality of twoPhaseEulerFoam, I went back to basics and tried to do something really "simple". What i wanted to do is a box, with a layer of solids at the bottom, and above that just water. No inflow/outflow, just fluid at rest with sediment at the bottom of the box. I was expecting to see nothing happening. But velocities developed in the flow, out of nowhere.
I then tried removing the sediment, having just water in a box, no inflow/outflow. And again, some weird velocities develop. I have turned all turbulence etc.. off. I have tried buoyantPressure and zeroGradient BCs for pressure, and although the results are different, both result in some velocity in the box (see image, for t=1s). Have also tried an open boundary at the top but that didnt help either.
I have attached the case without sediment (however you can use the setFields file to add solids to the domain). I don't understand why the model is performing that way , I couldnt find a problem in my set-up, but if someone could check or explain i'd be very grateful.