geometry rotation

nimap · July 19, 2014, 09:11

hi friends,
i'm cfx beginer.i want to simulate this geometry(attached file) in Ansys CFX.those five hole are velocity inlet and that semicircle is pressure outlet and whole geometry rotate about X-Axis with 320mm radius.how can i define rotation for this geometry in cfx.
thanks a lot.

ghorrocks · July 20, 2014, 06:19

I do not understand what you are modelling. Can you show an oblique view? And where you expect the flow to go? And what is rotating and what is stationary?

nimap · July 20, 2014, 14:12

it's kind of turbine blade cooling(impingement cooling)air enter through 5 holes on rectangular surface and after impinge oposite conceve surface exite from semicircle surface.
all of this system rotate about X-axis(axis of rotation and jet axis are parallel).
in all of examples and tutorials like fans and rotor etc. we have rotation of solid deal with external flow but in this case i think sth different.
i attach another pic.
thank you for your attention.

ghorrocks · July 20, 2014, 18:27

This is simple - just put it in a rotating frame of reference and the rotation will be taken care of. Read up about the different frame of reference models - I think you will find frozen rotor will be adequate and that is a simple easy model to apply.

Have a look at the rotating machinery tutorials for how to set this up.

nimap · July 25, 2014, 04:22

thank you Glenn. i defined rotating frame in domain, in DM move geometry from x-axis to desired radius of rotation it seems works.
can i see the geometry rotation animation to have sight how does it rotate?
i tried but in animation,only shows stremlines or contours and dosn't show the way geometry rotate!!

ghorrocks · July 25, 2014, 06:25

Frozen rotor simulations do not rotate the mesh. They add the rotation terms to the NS equations so you can use a stationary mesh. If this approximation is valid it makes the simulation a whole heap easier.

nimap · August 6, 2014, 00:10

Hi Glenn.excuse fo my delay.i checked Ansys help,it seems use frozen rotor for external flow like fan and rotor...
how about define rotating in Domain motion instead of stationary in this path(simulation>flow analysis>default domain).

ghorrocks · August 6, 2014, 08:24

I do not understand your question.

nimap · August 13, 2014, 01:46

i mean in cfx-pre,this path in outline tree(simulation>flowanalysis>default domain) define rotating instead of stationary in Domain motion

ghorrocks · August 13, 2014, 06:11

If you define the domain as rotating then you either activate the rotational modifications to the equations (if one of the stationary mesh models like frozen rotor) or it rotates the mesh (if transient rotor stator).

If you define it as stationary then the domain is stationary.

July 20, 2014, 06:19		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	I do not understand what you are modelling. Can you show an oblique view? And where you expect the flow to go? And what is rotating and what is stationary? nimap likes this.

July 20, 2014, 18:27		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	This is simple - just put it in a rotating frame of reference and the rotation will be taken care of. Read up about the different frame of reference models - I think you will find frozen rotor will be adequate and that is a simple easy model to apply. Have a look at the rotating machinery tutorials for how to set this up. nimap likes this.

July 25, 2014, 06:25		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	Frozen rotor simulations do not rotate the mesh. They add the rotation terms to the NS equations so you can use a stationary mesh. If this approximation is valid it makes the simulation a whole heap easier. nimap likes this.

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July 25, 2014, 04:22		#5
nimap New Member nima Join Date: Jul 2014 Posts: 9 Rep Power: 11	thank you Glenn. i defined rotating frame in domain, in DM move geometry from x-axis to desired radius of rotation it seems works. can i see the geometry rotation animation to have sight how does it rotate? i tried but in animation,only shows stremlines or contours and dosn't show the way geometry rotate!!

August 6, 2014, 00:10		#7
nimap New Member nima Join Date: Jul 2014 Posts: 9 Rep Power: 11	Hi Glenn.excuse fo my delay.i checked Ansys help,it seems use frozen rotor for external flow like fan and rotor... how about define rotating in Domain motion instead of stationary in this path(simulation>flow analysis>default domain).

August 6, 2014, 08:24		#8
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	I do not understand your question.

August 13, 2014, 01:46		#9
nimap New Member nima Join Date: Jul 2014 Posts: 9 Rep Power: 11	i mean in cfx-pre,this path in outline tree(simulation>flowanalysis>default domain) define rotating instead of stationary in Domain motion

August 13, 2014, 06:11		#10
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	If you define the domain as rotating then you either activate the rotational modifications to the equations (if one of the stationary mesh models like frozen rotor) or it rotates the mesh (if transient rotor stator). If you define it as stationary then the domain is stationary.