Flow over rotating sphere

 Register Blogs Members List Search Today's Posts Mark Forums Read

 August 11, 2009, 03:57 Flow over rotating sphere #1 Member   mistry Join Date: Apr 2009 Location: India Posts: 69 Rep Power: 10 Sponsored Links Hi all i want to do analysis of flow over rotating sphere.problem is: to specify rotating domain in CFX Pre i found when i specify sphere as solid domain it is not giving be rotaion option when i specify fluid domain it only gives me option how to solve problem... secondly i think SST model is best for the selection any suggestion? how to specify FSinterface... here Please guide me.

 August 11, 2009, 08:16 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 13,725 Rep Power: 106 Hi, Assuming you are modelling flow over a rotating sphere with a known velocity then forget about solids, rotating domains or multiple domains. Just have a single domain with the sphere cut out of it. To impose the sphere rotation give the sphere walls a tangential velocity. I think the easiest way to apply this velocity is using a CEL expression to give velocity on the sphere surface as a function of XYZ location - this is easy providing the sphere location is known and the rotation rate is known. As for which turbulence model is best - that depends on what you are trying to get out of the model and what Reynolds number and Mach number you are running at. SST is a good general purpose one but there are cases when it is not appropriate. Glenn Horrocks

 August 11, 2009, 09:02 Rotating sphere #3 Member   mistry Join Date: Apr 2009 Location: India Posts: 69 Rep Power: 10 Sir, Really your quick reply energied me do continuous work on CFD... may i get any hint how to specify rotational velocity using CEL on sphere surface. my idea is to specify inlet region velocity need to specify. My inlet velocity is 3 m/s and diameter of sphere is 1,1.5 m ,rotational speed 100rpm,150,200 and want to study pressure,velocity distribution on outer surface. please Guide me.

 August 11, 2009, 19:07 #4 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 13,725 Rep Power: 106 As I said, it is a pretty basic CEL expression to give the sphere a rotating wall. You should be able to derive the expression yourself once you understand the basics of CEL. Have a look in the tutorial examples for some examples of how to use CEL. Glenn Horrocks

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post prapanj OpenFOAM Running, Solving & CFD 0 March 17, 2009 02:20 Francis Main CFD Forum 0 September 29, 2008 05:16 Steve FLUENT 0 April 17, 2003 12:37 arash Main CFD Forum 0 January 20, 2002 14:49 Axel Rohde Main CFD Forum 1 November 19, 2001 13:19