# Simulation of object in rotation

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 March 21, 2008, 12:38 Simulation of object in rotation #1 Dothan Guest   Posts: n/a Hi, I'm working with Fluent for simulate the influence of an object that rotate in air. I've created a volume and I've subtracted my object, so I obtain the walls that rappresent my object. Now, How can I use the boundary condition for simulate the rotation? -I can't set only the wall velocity because, like manual say, this method trasmit only tangential forces and isn't suitable for movement that is normal to wall. -If I use Single Reference Frame rotation, fluid->moving reference frame in rotation with the angular velocity opposite than the object angular velocity, and I set the object to be stationary in the absolute frame, I think this method don't model the real phenomenon. ( for example: SRF introduce a radial gradient of pressure). So, How can I model this problem in a suitable manner? tnx

 March 22, 2008, 18:57 Re: Simulation of object in rotation #2 Hirdesh Guest   Posts: n/a Hi, As object is rotating in air i.e. outer domain should remain stationary. Use MRF instead of SRF. make two zones. one rotaiong zone that include rotating object. Another one is stationay outer zone. I hope this will help you. Hirdesh

 March 23, 2008, 15:45 Re: Simulation of object in rotation #3 Stefano Guest   Posts: n/a Hi, I perform a simulation of a helicopter's blade and I have used the stationary condition for the wall and the MRF for the fluid too.So I have got a good results. I hope to be helpful. Bye

 March 23, 2008, 15:46 Re: Simulation of object in rotation #4 Stefano Guest   Posts: n/a Hi, I perform a simulation of a helicopter's blade and I have used the stationary condition for the wall and the MRF for the fluid too.So I have got a good results. I hope to be helpful. Bye

 March 25, 2008, 04:25 Re: Simulation of object in rotation #5 Dothan Guest   Posts: n/a Hi, many thanks for yours replies. If I have undestand,I can applicate the same method showed in the Tutorial #9 "Using Multiple Rotating Reference Frames", Fluent documentation 6.3. So I must create a fluid volume which contains the fluid near my "wall" object ( if I incorporate some fluid far from my object I think this isn't correct, isn't?). I must associate this volume at the first reference frame, with angular velocity equal and opposite than object velocity. The second rotating reference frame is referred to the ambient volume, and is stationary. A question: The fluid in the first rotating reference frame near my object I impose that it is rotating, but in the real problem it isn't moving. Is this correct? tnx Dothan