- **NUMECA**
(*https://www.cfd-online.com/Forums/numeca/*)

- - **k and epsilon**
(*https://www.cfd-online.com/Forums/numeca/77542-k-epsilon.html*)

k and epsilonDear all,
I want to model a centrifugal pump in NUMECA using k-eps turbulence model, how ever I just have intensity and length scale at inlet, how can I convert intensity and length scale to k and epsilon at inlet ? sincerely |

Dear Hamed;
if pump inlet velocity is known, ( inlet velocity may be calculated by knowing pump flow rate and pump suction side diameter) you can find k from turbulence intensity relation. calculated k can be applied to length scale relation to find epsilon. does it help? |

Hi Amed,
Sorry because the late answer. As you know, k is the kinetic energy and epsilon is the disipation of turbulence. We could consider epsilon as 0.1*k. The kinetic energy k, can be calculated as: k=3/2 (T*U)^2, where T is the Temperature of the problem, and U is the inlet velocity. I hope I'll be helpful. Cheers |

TuHi,
Sorry because of the definition of the other day. As you know in a turbulence model, the units for k are [m^2/s^2]. I was wrong saying T was the temperature of the model, T is is a percentatge that represents the turbulence intensity factor as I've seen on biography. I realise because of my job results, intensity of the turbulence and the poor disipation.T = 0.05-0.10 (biography, fluctuations respecte wind velocity)U= inlet velocity Sorry if someone have run their jobs after my definition of k but I wouldn't get results yet. k= 3/2(T*U)^2 epsilon = 0.1*k Greatings, sanboju |

All times are GMT -4. The time now is 05:41. |