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Short August 30, 2001 12:45

Contaminant distribution
Assuming I wish to study contaminant distribution in an enclosure and already have the flow field calculated what is the best way of going about it without re-solving the continuity and momentum equations?

I know how to specify the contaminant location and generation rate.

Kike August 31, 2001 04:06

Re: Contaminant distribution
Dear Short

In principle, I think there is no way to do so. In such a systems the evolution of the flow field will depend on mixture between the contaminant and the base fluid. New values for density and viscosity should be included into eqs. for cell that contain both species.

I am afraid you will have to rerun your case including your contaminant sources.



John C. Chien August 31, 2001 23:46

Re: Contaminant distribution
(1). If the contaminant does not interact with air , and if the existence of the contaminant does not affect the computed velocity field, then you can compute the contaminant convection and diffusion separately. (2). That is, use the known velocity field for the convection terms. You will have to determine the diffusion coefficient for the contaminant in air or something like that. (3). You can also use the velocity field to do fluid particla tracing. and this will include the convection effect.(no diffusion) At least you can get a rough idea about the movement of the contaminant.

Mike Malin September 3, 2001 07:16

Re: Contaminant distribution
If the contaminant is passive, i.e. it does not influence the mean density field, then it should be possible to a RESTART calculation from the converged hydrodynamics field solving only for C1 (say) with the hydrodyamic field variables STOREd rather than SOLVEd. The turbulent and laminar Schmidt numbers are defaulted to unity, but can be changed via the input variables PRT(C1) and PRNDTL(C1).

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