Dispersion Modelling

John

Dear All

I am looking to model the movement of a plume of dye through a pipe flowing full with water (Re = 30000). The dye has the same density as the water and there is no chemical reaction. It appears there is two ways to do this in Fluent; through particle tracking and species modelling. I have played around with the two methods and they give different results for the parameter of interest. I have looked at the equations of motion for each method in the fluent manuals, but I am unsure that I have come to the correct conclusions so I am hoping someone can confirm (or correct me!) on the following.

When referring to equation 11.2.1 only the first three terms remain for my situation. The term J will be dominated by ut which comes from k and eps when using this model. Therefore does this mean the movement of dye is dominated by turbulence and not velocity gradients?

When using particle tracking with the stochastic model turned off the particles will move according the velocity field. When the stochastic model is turned on they deviate according a random function linked to the turbulent intensity.

If anyone has any further help or comments I will greatly appreciate it.

Regards, John