Say if I have 50 impellers on a shaft. Do i have to create 50 bodies around the impellers and assign them as rotating regions or create a single cylinder covering all bodies and assign it as rotating region ?
depends on the problem. If they are close together and nothing in between (like stators) then then one might work. Do you understand the rotating frame approximation? If you do then the answer is obvious.
If they are all rotating on a single shaft at the same angular velocity, then you should just just one rotating body. This is assuming, as Bill said, that you are applying it correctly to an appropriate model.
Yes, I do know that the equations are solved in moving reference frame by translating velocity (either to relative velocity or absolute velocity).
It does make sense that if all the impellers are close and have same axis of rotation and angular velocity, one cylinder would be enough. Thanks.
I have one more question.
My solver is abnormally terminating.
My boundary wall is so close to the cylinder ( rotating body) . Do you think that might be the problem?
put the boundary into the wall. try and get 2-5 cells between impeller tip and wall
check the solving engineering problems document
"terminating abnormally" may mean that your model isn't good, your mesh isn't good, or that you aren't following the rules of the road for rotating regions
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