Should I use Realizable K-epsilon model in my problem?

- November 7, 2020 at 3:11 pm
  
  SEANGHAI
  Subscriber
  
  Hello! In fluent, how can I know that which type of K-epsilon model should I use for my problem? For example; Standard K-epsilon model and Realizable K-epsilon model, which one should I use? I saw some different equations of these two models of K-epsilon model, I know that the difference between Realizable and Standard model is the viscosity coefficient and the dissipation equation. But I want to know the exact purpose to use each one model. Because in my problem, I have to apply source term, sink, mass flow inlet and mass flow outlet in one domain and also I have pressure Outlet, so when I use the Standard K-epsilon model, the solution is not converged, but when I use Realizable K-epsilon model, the solution is converged. Thank you in advanced!n
- November 9, 2020 at 1:48 pm
  
  Karthik Remella
  Administrator
  
  Hi,nUnfortunately, there is no universal turbulence model and the choice of the model depends on the flow physics and engineering application.nThe Standard k-epsilon model can be sometimes diffusive in nature especially for applications involving a strong swirl flow component. The realizable k-epsilon model tends to overcome this limitation. Because of this, the realizable model generally tends to perform slightly better. nHaving said that, the default k-omega SST (in 2020R1 and R2) should be robust enough to model most engineering application. Please take a look at this link from the Fluent's user guide on 13.2. Choosing a Turbulence Model.nThank you.nKarthikn
- November 10, 2020 at 4:41 am
  
  SEANGHAI
  Subscriber
  
  Thank You!n