[Thcfd]

Hello everyone,

I´m having a small problem with the way CFX stretches or compresses the flowfield when an interface with pitch change is used. Here is my Problem:

I´m currently working on the simulation of a turbine testrig. The rig consists of 4 bladerows of which the 3d one is the rotor. Now, due to the number of blades in each row (and of course time and memory requirements) i´m forced to use interfaces with a pitch change.
When i´m trying to do a simulation with a Frozen Rotor Interface (regardless whether steady state or transient), CFX stretches the flowfield between the interfaces as discribed in the manual. I´ve added two small pictures of a geometry that i used to test different interface configurations, where you can see the stretching cfx performs.

This of course gives a rather wrong flowfield after an interface with a high pitch change (stretching of the wakes etc). In my case the pitch change after the rotor is from 15° to 24°, where the domain with the 24° is the one i´m most interested in. What i have seen from a few things that i have tried is, that CFX is able to "add" information to an interface by periodically adding data to the interface (i tried periodic domains with a different "lean" at the interface).

My question is now whether there is a possibillity to prohibit the stretching on the interface, but to force the solver to do the add the information on side 2 of the interface by periodically copying the information from side 1


I hope that somebody is able to give me any advice or ideas how to solve the issue.

thank you