[sinatahmooresi]

Hello dear FOAMers.
I am dealing with different k-e family turbulence models (standard, RNG, and realizable). I am trying to find the best model to simulate dense jets (jets with higher density than the ambient which they released in). But there is a huge difference between the results of RNG and realizable. The most challenging part to me is that the RNG produces a fully reasonable pattern (The distribution is totally moves along where the body of the flow moves) for nut (eddy viscosity), see the figure please. However, it is not happening for realizable! There is a bump like (the concentrated part) above the main flow which moves during the simulation time and influence the scalar field distribution and results. For example results of realizable k-e in terms of scalar distribution are so conservative (under estimation the experimental results).
We usually expect to see better performance of realizable k-e in compare with other versions of k-e family, specifically in turbulent round jets. Does anybody have experience on related to this? Why realizable is performing so weird in terms of eddy viscosity?



It is worth noting that all the simulations’ conditions are equal except for the turbulence models. ( selected pictures are from two different inclination of jets: 30 and 45 degree. inclination makes no different in these patterns of answers at all, based numerious simualtions in different inclinations (angles of discharge)).





Regarsds
I could not attach the distribution of epsilon in realizbel simualtion. it is almost close to RNG one

[sinatahmooresi]

67 persons have already seen the thread, no anwser???!!!