Turbulence dispersion
 

Hi,

I deal with a model, which is quite simple. It consists of an air flow in a tunnel with rectangular cross section and droplets injected from the tunnel side wall. My task is that turbulent dispersion influence should be seen clearly from the results (by oscillations of droplets trajectory). Here the problem begins. I can't achieve the picture that was obtained experimentally. Droplets trajectory stays straight... Can you give me some advise?

Regards,

Julie

Re: Turbulence dispersion
 

First of all, I think the turbulent dispersion model in STAR is quite simple. Secondly, according to my own experience the flow field as well as the spray injection characteristics influence how much the droplet trajectories are influenced by the dispersion model. For example, if you have a strong turbulent field where you inject droplets then the drops are likely to be more influenced by the dispersion model than if the fluid where you inject the drops is almost laminar. Additionally, the higher the relative drop velocities are, the less the dispersion model will affect their trajectories, e.g. in high speed diesel engine sprays the drop trajectories are not much affected by the turbulent dispersion model.