# Propeller in the ATmosphere

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 March 6, 2011, 12:36 Propeller in the ATmosphere #1 New Member   Mido Join Date: Mar 2011 Posts: 24 Rep Power: 11 Hello MyName is Mohammed i am still new at this so i appreciate help in as much details as possible my problem is that i want to do propeller simulation in atmosphere i made CAD of the propeller in a cylindrical domain but I have two problems (1) the BC (inlet , outlet , sides of the cylinder) (2) the i heard that i need to put not in 1 rotating domain but in 2 domain the outer is stationary and the inner is rotating if you need the CAD of the propeller my email is public i can send it for you thank you very much I appreciate fast reply thank you

 March 6, 2011, 18:01 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 16,542 Rep Power: 128 You only need the out stationary domain if it contains some stationary geometry. If you only have the propeller (or everything rotates with it) then just use a single rotating domain.

 March 6, 2011, 19:44 RE #3 New Member   Mido Join Date: Mar 2011 Posts: 24 Rep Power: 11 what about the BC ??

 March 7, 2011, 08:29 #4 Senior Member     Attesz Join Date: Mar 2009 Location: Munich Posts: 367 Rep Power: 13 I imagine your problem, and i think you should do these steps: 1. define the rotor domain, which includes only the rotor walls and the air close to it. you dont have to model the solid of the rotor (i assume). Set the rotational domains with the desired rotating velocity 2. define 2 domains at the "inlet" and "outlet" sides of the rotor as stationary domains. 3. there will be 2 interfaces between them, look in the help for frozen rotor and stage options and suggestions 4. i would use opening as boundary condition everywhere, and setting 0 pa relative pressure and environmental temperature. of course you can use inlet and outlet, they are numerically stable except there are backflows (wall placed on...well known issue). use opening first on the other hand, look in the compressor tutorial, which is very same to yours problem. rotor, compressor wheel...doesn't matter

 Tags cfx, propeller