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June 1, 2009, 11:19 |
Star-CD and K-Epsilon turbulence model
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#1 |
Member
Hamoudi djamel
Join Date: Apr 2009
Posts: 50
Rep Power: 17 |
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= Mixing Length = 0.07 Epsilon = 1,25 e +04 My simulation diverge always Please I am waiting for your Answers ****** Is this possible ******** |
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June 2, 2009, 13:00 |
Hi
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#2 |
New Member
Join Date: May 2009
Posts: 3
Rep Power: 16 |
Hi,
can I get your one which you are doing.. because I am working on k-e model. thanks gmg |
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June 2, 2009, 13:02 |
Hi
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#3 |
New Member
Join Date: May 2009
Posts: 3
Rep Power: 16 |
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June 5, 2009, 06:02 |
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#4 |
Member
Join Date: Mar 2009
Posts: 55
Rep Power: 17 |
Try using smaller URF for k and e to start the case and then later on increase as the solution has run for a few iterations and stabilised. You could also initiate the solution with smaller value of k. General k-e models under-predict the 'spread' of k values from meanline in jet modeling.
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