axis of rotation for free motion

[Anonymous]

Hi, 

I am running a simulation with motion. I am able to assign a part to be able to rotate in Z dirction, but how can I specifiy the axis of rotation? and what is the default axis of rotation. I find 'angular motion' has this option but not 'free motion' yet. 

Thanks

Gubing 

[Jon.Wilde]

Hi,

Is this only able to rotate in one axis? What are you modelling?

Thanks,

Jon

[Anonymous]

Hi Jon, It can rotate in all degrees of freedom, and it is a general question when i setting up my model. It applies to all the models. When I check 'RotationX' in free motion, I cannot specify the 'axis of rotation'. This link shows how axis of rotation can be assigned for angular motion : https://knowledge.autodesk.com/support/cfd/learn-explore/caas/CloudHelp/cloudhelp/2014/ENU/SimCFD/fi... Thanks Gubing Wang Industrial Placement Student PSDE - Device Eng - UK RD Platform Technology & Science GSK Priory Street, Ware, Hertfordshire, SG12 0DJ, United Kingdom Email gubing.x.wang@gsk.com Tel +44 1920 88 3132 ________________________________ This e-mail was sent by GlaxoSmithKline Services Unlimited (registered in England and Wales No. 1047315), which is a member of the GlaxoSmithKline group of companies. The registered address of GlaxoSmithKline Services Unlimited is 980 Great West Road, Brentford, Middlesex TW8 9GS.

[Jon.Wilde]

I think it means it can just rotate around any axis in this plane, rather than setting a specific axis. That would be a different type of motion analysis.

[Anonymous]

thanks Jon, when I play the animation after simulation, it appears that the object is rotating about the axis where its center of mass passes through?! So I guess u mean: "RotationX=any axis in planeYZ"? if it just rotate around any axis, would the result be any useful? when do people use this feature then? Thanks, Gubing

[apolo_vanderberg · Accepted solution]

Gubing -

 I'm not sure we are following your specific needs for motin here.

Angular motion we are constrained to having a single axis of rotation (think pump impeller, fan blade, or angular check valve). As a result we have to pick the axis that this rotation occurs around.

Free motion, by definition is more as it sounds in that we are allowing the part to react to the flow field within certain limits. Such that if you wanted to see a ball falling out of the sky it can translate in Global X/Y/Z, or it can rotate about X/Y/Z.

If you'd like to outline what you are trying to model we can advise how to best leverate either Angular or Free motion to suit your application.

[Anonymous]

Thanks Apolo, in my case, there is an axis passing through the capsule, and the capsule is able to rotate back and forth around the axis, and the rotation is driven by air.



________________________________

This e-mail was sent by GlaxoSmithKline Services Unlimited
(registered in England and Wales No. 1047315), which is a
member of the GlaxoSmithKline group of companies. The
registered address of GlaxoSmithKline Services Unlimited
is 980 Great West Road, Brentford, Middlesex TW8 9GS.

[Anonymous]

and so I guess in my case it should be angular motion with flow driven?

[Jon.Wilde]

This sounds more sensible to me 🙂