Hi,

I am thinking about writing a code for two phase gas -particle supersonic flows. I have a few questions:

Under what conditions can the particulate phase be treated as a compressible continuum?

How do you account for particle size distribution and particle-particle collision?

I appreciate any comments or references

Shuo

There will be about 3 ranges of particle size that you want to consider/differentiate.

A) When the particle are small enough (and that depends also on their density relative to the density fo the gas), then they will act like tracers in the flow and will follow exactly the same path as the flow elements (dragged, tracers).

B) When the particles are very large (and if an external force such as gravity is acting on them) they will not be affected by the fluid, except for some drag.

In the intermediate regime (between A and B) the particles will have a behaviour very different than the gas itself (A) and than the particles alone (B).

So you basically need to divide your particles in 3 groups as these 3 groups will have distinct behaviour. More than 3 might be more than what you need.

As to collision, and aggregation and possible coagulation, this is done by including some semi-analytical treatments in your two phase flow equations.

I have a background in astrophysics, so I can only give you some references there.

Go to http://xxx.lanl.gov/

that's a free website with free downloadable pdf articles in very different fields, from astrophysics to biological physics... it is all about physics... so you can look into the astro part, computational part, or fluid dynamics and make a search using the appropriate keywords such as dust and gas, two phase flow, dust and vortex/vortices, ...

Try names in astrophysics such as Barge, p.; Inaba, S., Sommeria, J.; ...

good luck!