In this example, a tube is create by a pair of periodic walls. The walls are individually created from two periodic lines and then a network struts holds the walls together. The flow is driven with a background force in the x direction. The IBIS file that creates the simulation in this case is:
domain 0.0 2.0 0.0 1.0 grid 6 0.0000165 1000 visual -h 256 -w 512 -n 20 -p binary -b bryo -y graph -n 100 -p line -b bryol # # fluid properties and background force # fluid -m 0.01 -r 1.0 bforce -x 500.0 -b 0.1 -t 0.9 particles -d 4 # # reset default springs for lines and links # spring l -b 100000.0 -s 40000000. -t 10000000. spring L -s 40000000. # # bottom wall # line 0.0 0.1 2.0 0.1 -N 1 line 0.0 0.08 2.0 0.08 -N 2 blink 1 2 # # top wall # line 0.0 0.9 2.0 0.9 -N 3 line 0.0 0.92 2.0 0.92 -N 4 blink 3 4
In this simple simulation, there are no active entities and no sources or sinks of fluid. Therefore, the standard udefine.f will suffice to run the simulation.
A graph of nearly steady flow for this simulation is shown in the next figure.