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-   -   Free surface flows with solid transport (http://www.cfd-online.com/Forums/cfx/18677-free-surface-flows-solid-transport.html)

Patrice Jaumouillie October 12, 2001 10:57

Free surface flows with solid transport
 
Hello everybody.

I have to modelize a free surface flow with solid transport of suspended matters in sewers.

The only parameters i know for the suspended matters are their mass fraction and their settling velocity.

Like my particles are small and diluted, i suppose there are not any particle/particle interaction and particle/fluid interaction (the flow is not coupled).

What is the best way to modelize this problem ? Can i use the multi component multi fluid model with a settling velocity ?

Can i use the multi fluid model with a solid dispersed phase with only the settling velocity ?

Can i use the homogeneous model with a solid phase ?

Thank you for your help.

PJ

Herve October 15, 2001 04:25

Re: Free surface flows with solid transport
 
I would say that in your case a three-phase approach seems to be what you want, esp. because you seem to imply that the phases are not very coupled (homogeneous wouldn't match this description). But is the free-durface really needed as such?

Patrice Jaumouillie October 15, 2001 04:33

Re: Free surface flows with solid transport
 
I need a free surface because my flow is transient, in sewers the water level quickly change. And in the curves, the water level is different at the intrados and at the extratos, this level difference is caused by the inertia of the fluid.

A three phase approach, using the IPSA model will take a month to converge with my workstation.

Andrea Maffio November 5, 2001 10:31

Re: Free surface flows with solid transport
 
Hi, I'm involved with a similar multiphase problem with sediment erosion and changing water surface level. The three-phases (sediment/disperse, water/continuous, air/continuos) approach didn't work in my case, because no stable solution at the air-water interface was obtained (the momentum homogeneous is not applicable). Now I'm trying the same problem with only two phase (sediment and water)and using USRGRD subroutine for the free surface movement.


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