[pxy0076]

Hello all,
I am new to fluent and I have a lot of queries. Please help me out with the following
I will be performing analysis on a horizontal tube with flow being turbulent and also a two-phase flow. A real world application is the central receiver tube of a Concentrated solar Power ( CSP).
1.Modelling
How am I supposed to create the model, 2D or 3D?
And why "answer"
If I am going to model a 3D tube , Should I design the entire tube or just 1/4 of the tube.
2.Establishing domains
If I am going ahead with 1/4 tube model, How am I supposed to establish domain.
And after seeing a lot of tutorials on domain creation, I have met with this confusion. Should I create a cavity and then establish it as a fluid domain or Should I leave it as a entire solid model without cavity and establish the centro region as fluid domain ?