[AS_Aero]

Hi All

I am doing a simple in-compressible flow (water as medium) inside a twisted pipe/cylinder. Here I am doing an LES computation using CFX and for that I am confused, on what basis I should give my mesh size and time step. And can use Hex mesh or Tetrahedrals ? (Some say Hexamesh is not good for CFD though)

The flow inlet is 5 bar and mass flow rate is 10 l/min
The geometry is total lenght of 23 mm, Inlet diameter of the pipe is 7mm
after 20mm distance the pipe is twisted and a difuser is connected at the end to act like a nozzle. Based on the flow conditions we can say the Reynolds number is around 10000 at the pipe inlet

So in this case I am confused how to decide the mesh size (if I should give the minimum mesh size in Ansys mesh which controls the entire mesh or how to proceed) and the time step. Kindly give me some advice please.

Thanks