problems about MRF model

December 14, 2002, 00:56

Hi: I am simulating a small centrifugal pump(a inlet and an outlet)using mutiple rotating reference frame .The model of my pump (only remains fluid zones and wall)cosists of two parts ,one is the rotating part which is set to a rotating reference frame ,the other is stationary part.The result is :the stationary part are ok,but the rotating part only has absolute velocity (its direction is same as the direction of rotation,maybe wrong),and I cannot find the relative velocity along the flow paths ,which is very important for me .Expecting your help!Thanks a lots!

Salman · July 23, 2009, 20:25

Hi,
I have the same problem. I could not get any rel velocity vectors etc. using MRF for an axial fan.
My colleagues have adviced me to calculate the rel vel from the abs vel in Ensight and then do the post processing like streamlines or vel vectors.
Now the problem is how can one calculate the relative velocity from the abs vel for all the zones (rotating) of such a problem.
is there any solution already available in some text/code or software. Your help is kindly and urgently requested, please.

biget.a · July 24, 2009, 04:14

Hi, i don't know if it's help you but you can change the reference zone (moving zone or steady zone) in reference values menu.

Salman · July 24, 2009, 10:05

hi, it worked superbly. Thanks a lot.
Now I am not sure that should I make this setting before initialisation or not?
Also now if I try to export the already simulated case from fluent to ensight with the modifiied reference zone setting, will it behave in the same manner or not. otherwise do I have to simulate again?
I am working on export to ensight right now, hopefully it wont disappoint me.

anyways thanks once again... u made my day!!!!

December 14, 2002, 00:56	problems about MRF model	#1
lingo Guest Posts: n/a	Hi: I am simulating a small centrifugal pump(a inlet and an outlet)using mutiple rotating reference frame .The model of my pump (only remains fluid zones and wall)cosists of two parts ,one is the rotating part which is set to a rotating reference frame ,the other is stationary part.The result is :the stationary part are ok,but the rotating part only has absolute velocity (its direction is same as the direction of rotation,maybe wrong),and I cannot find the relative velocity along the flow paths ,which is very important for me .Expecting your help!Thanks a lots!

July 23, 2009, 20:25	calculating relative velocity from the absolute velocity	#2
Salman New Member Salman Join Date: May 2009 Posts: 11 Rep Power: 17	Hi, I have the same problem. I could not get any rel velocity vectors etc. using MRF for an axial fan. My colleagues have adviced me to calculate the rel vel from the abs vel in Ensight and then do the post processing like streamlines or vel vectors. Now the problem is how can one calculate the relative velocity from the abs vel for all the zones (rotating) of such a problem. is there any solution already available in some text/code or software. Your help is kindly and urgently requested, please.

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July 24, 2009, 04:14		#3
biget.a New Member biget.a Join Date: Jul 2009 Location: Nancy Posts: 3 Rep Power: 17	Hi, i don't know if it's help you but you can change the reference zone (moving zone or steady zone) in reference values menu.

July 24, 2009, 10:05		#4
Salman New Member Salman Join Date: May 2009 Posts: 11 Rep Power: 17	hi, it worked superbly. Thanks a lot. Now I am not sure that should I make this setting before initialisation or not? Also now if I try to export the already simulated case from fluent to ensight with the modifiied reference zone setting, will it behave in the same manner or not. otherwise do I have to simulate again? I am working on export to ensight right now, hopefully it wont disappoint me. anyways thanks once again... u made my day!!!!