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-   -   dpm-stochastic particle tracking (http://www.cfd-online.com/Forums/fluent/32193-dpm-stochastic-particle-tracking.html)

Anna Blioebig September 24, 2003 01:37

dpm-stochastic particle tracking
 
Hi all,

I'd like to use the stochastic particle tracking for turbulent dispersion of particles in a turbulent flow. I followed the instructions in the ug but in my case the "number of tries" option is always inactiv and not selectable. Can anybody tell me a reason for this? How can I be sure that the turbulent dispersion of particles will be included by FLUENT? What do I have to do that this option will be selectable?

Brief discription of my settings: Flow field: seg-solver, rsm-turbulence model, steady, 3d. After convergence of the flow field I introduced particles using the dpm-model dpm-setup: single injection, flow rate 0kg/s, dp=4e-6m, inert particles, stochastic model: random eddy life time - time constant 0.3.

Thanks for all helpfull replies

Anna

Ben September 24, 2003 03:52

Re: dpm-stochastic particle tracking
 
Try a group injection not a single injection. Also why is your flow rate set to 0kg/s. This cannot be set to 0kg/s.

When using the DPM approach you inject in a particle stream (or streams). The stream is characterised by it's strength, which is determined by the number of particles within the stream that pass a point per second.


Anna Bliebig September 24, 2003 07:03

Re: dpm-stochastic particle tracking
 
I included your advices in my calculation but it didn't solve my problem so I returned to the old settings.

A 'group injection' is used if you want to set the defined initial conditions (d_p, T_p, x-, y-,z-coordinates..) between a certain range (see ug 19.9.2). Then FLUENT uses a linear variation between first and last value.

I use a mass flow rate of 0kg/s because for uncoupled calculations it isn't necessary to specify a value (see ug 19.9.5).

Over the several attempts to make the 'number of tries' check-box selectable I noticed that for me it isn't possible to use the cloud tracking model. But it is selcetable in the 'set multiple injections properties' panel - that seems funny to me. Are there any exlpanations for this?

Anna


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