I opted to graph the results at the isosurface level 0.6 as this gave reasonable results throughtout the whole time period.
Here are the results when I didn't impose a flow at all, i.e v=(0,0,0). As we can see, the tubes are diffused, but no advection occurs.
Here are the results when I ran my Fortran program with v=(0,cos(2*pi*x),0).
Here, I set v=(0,0,6).
The results below are a combination of the 2 above, i.e. v=(0,cos(2*pi*x),6).
Click here to see the third picture above enlarged and compared with the same image but with 30 meshpoints.
Finally, I have imposed a flow along the cylinders. Clearly, I didn't expect to see the cylinders move, since their shape is uniform in the direction of the motion; I wanted to plot this anyway, as a check that my periodic boundary conditions work in the y-z plane.
I used the flow v=(3,0,0).
