Hello,

has anyone experience with intermittency transport models for (successfully) simulating the transition over a separation bubble, especially in Fluent? Any comments will be appreciated.

Thanks, Dirk

Hi,

I am modeling intermittency using STAR CD. I will be using my model to calculate flow over turbine blades which will be highly prone to seperation.

Since you hav'nt mentioned excatly what you need to know, I will give you a rough idea of what to do based on what I am doing.

Solve the intermittency equation as a scalar. In STAR CD we have the option to solve for a scalar and supply the source and diffusion terms via user defined subroutines. I am pretty sure similar options are available in Fluent. You have to be very careful with boundary integral variables, such as boundary lare thickness, momentum thickness etc as accuracy of intermittency calculation depend greatly on these. In STAR CD, we have no option but to write our own program for these variables.

Once the intermittency is solved properly, it is then neede to be incorporated into the actual flow calculation. According to the model I am using, intermittency comes into play only in momentum equation. It enters the momentum equation by changing the turbulent viscosity term,

mu_t_new = intermittency x mu_t_old

With regard to flow seperation, I am using intermittency model by Yildirim Bora Suzen. You can find relevant papers from this link http://www.engr.uky.edu/%7Esuzen/publications.html

Hope this helps. Good luck. Sheila