CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   Velocity fluctuation distribution near a wall (http://www.cfd-online.com/Forums/fluent/47121-velocity-fluctuation-distribution-near-wall.html)

Matthieu January 24, 2008 11:48

Velocity fluctuation distribution near a wall
 
Hello,

I am using Fluent 3d for simulating the trajectories of particles in a detention tank. The particles are assumed to be a discrete phase in a turbulent water flow. So, I am using the Discrete Random Walk Model in order to take into the effect of the turbulence on the particle motion.

Each eddy is defined by a Gaussian distributed random velocity fluctuation u', v', and w'. But near the bed, the velocity fluctuation is not Gaussian anymore (especially the vertical velocity) (because of bursts). So, I would like to define my own distributions for the velocity fluctuations near the bed.

Does someone know how I can access these distributions and modify them in an User Defined Function ? I would like to keep the Gaussian distribution when the wall unit, y*, is superior to a threshold value, and use my own distributions when y* is inferior to this value. Does someone have another idea to model the influence of burst on particle motion ?

Matthieu


All times are GMT -4. The time now is 19:26.