Dear freinds,

I am simulating the two turbine stage: High pressure and low pressure rotating in oppositve direction namely +ve Z axia and -ve Z axis.

I would like to ask the question how to give the boundary condition to fluid for this setup i.e two turbine rotating in opposite dirction.

Should i set +ve rotating direction for one and -ve rotating direction for other. when i do like this i get severe divergence.

Please help I am stuck up in my thesis work and it is last part of my work Regards SAM

Which code are u using

I am using Fluent and mixing plane model But I have no idea what to do when simulating couterrotating turbine. Do I need some special UDF?

Regards Sam

User Coordinate Systems

Dear A.S and Ahmed, thanks for your reply. But still i have problem in simulating two turbine on different shafts and rotating in different directions (i.e opposite to each other). I am facing high level of divergence.

I am looking for more comments and experts opinion from all users of cfd online and representatives of commercial cfd software vendors.

p.s 1. I have simulated both of them in isolation with succesful results. 2. What is meant by user coordinate system.

Regards