Issues with inlet/outlet boundary conditions in 3D
Hi,
I have been trying to build a simple 3D model: an object floats downstream in a flume (0.60 m x 1.20 m x 20.0 m; inter-particle distance = 0.015 m). The water depth is uniform and the velocity is uniform along the flume. I impose inlet/outlet boundary conditions as described in the 2D WATERMILL test case in the tutorial manual.
INPUT
Layers: 5
Refilling mode: Simple bellow Z Surface
Input Treatment mode: Remove fluid
Zone 2D/3D Zone 3D Mk fluid: 0 (with name “Inlet”) Direction: Right
Velocity mode: Fixed Velocity Type: Constant Value: 1 m/s
Density mode: Extrapolated from ghost nodes
Elevation type: Fixed Bottom level of water: 0 m Surface: 0.3 m
OUTPUT
Layers: 8
Refilling mode: Simple bellow Z Surface
Input Treatment mode: Convert fluid
Zone 2D/3D Zone 3D Mk fluid: 1 (with name “Outlet”) Direction: Left
Velocity mode: Fixed Velocity Type: Constant Value: -1 m/s
Density mode: Extrapolated from ghost nodes
Elevation: Fixed Zbottom: 0 m Zsurf: 0.3 m
However, I have two issues with these boundary conditions. First, after a few seconds, the water depth decreases as the flume is emptying out (although “Elevation type” is fixed). Second, when there are a few particles left in the inlet buffer zone, I see particles jumping in the air from the inlet buffer zone. If I carry out the same simulation in 2D, I do not see these issues. Why is this happening when I try to do the 3D simulation?
Thank you
Comments
Let us ask @taffo and @jmdalonso