# Star-CD and K-Epsilon turbulence model

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

 June 1, 2009, 11:57 Star-CD and K-Epsilon turbulence model #1 Member   Hamoudi djamel Join Date: Apr 2009 Posts: 50 Rep Power: 10 Sponsored Links Hello Everybody, I have a simulation on a numerical jet of air For this I use the Star-CD with Turbulence Model K-epsilon as you know at the beginning of the simulation we need to initialize the values of K and epsilon ( Energy and Dissipation rate of turbulence ) to calculate these two parameters Energy K = 3 / 2 * (U * I) Velocity of Jet . U = 286 m / s I= Intensity = 5 % K= 360,73 m2/s2 Epsilon Epsilon = (cmu 3 / 4) * K (3 / 2) / L cmu = 0,09, L= M ixing Length = 0.07 Epsilon = 1,25 e +04 My simulation diverge always Please I am waiting for your Answers ****** Is this possible ********

 July 16, 2009, 08:54 #2 Senior Member   matej forman Join Date: Mar 2009 Location: Brno, Czech Republic Posts: 117 Rep Power: 10 Hi, in fact you may specify the turbulence at inlet also by turb. intensity and length scale (usualy 0.1 - 0.07 of inlet diameter or characteristic size). With you high velocity do you calculate the flow as compressible and do you have correct setting of the pressure boundary? what is diverging, epsilon or continuity (pressure)? matej

 July 31, 2009, 05:34 #3 New Member   nick stoppelkamp Join Date: Jul 2009 Posts: 4 Rep Power: 10 Hi, I am having a somewhat similar problem. For a model i am only given the intensity and length scale for the turbulence model. How (and where) do I specify them in OF?

 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