long development zone
 

Dear all,
As we know, sometimes a very long development zone is needed for the velocity of the water becomes relative steady in a big pipe(In other words, the velocity profile becomes logarithmic). However, it will increase the length of the computation domain, so is the number of the grids. In addition, there is also a limitation for the number of the grids in flow3d.
So my question is, how can I
1.decrease the length of the computation domain?
or 2.can I create the special logarithmic velocity profile at the inlet boundary?

1. You can do a simulation of the pipe only and use a grid overlay boundary.
2. This is available with customization, but not in the standard code.