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Virtual mass force?

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Old   June 4, 2007, 00:58
Default Virtual mass force?
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bk
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Is there anyone who knows the physical meaning of virtual mass force in multiphase problem?

As I know, when a continuous phase density has larger than dispersed phase by order of 2 or 3, the virtual mass force will be important.

But in my case, the air(density=1kg/m3) is continuous phase and the solid particle (density=1000 kg/m3) is dispersed phase. In this case, can we neglect the virtual mass force?
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Old   June 5, 2007, 04:45
Default Re: Virtual mass force?
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Anton Lyaskin
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Virtual mass force comes from artificially spliting the drag force by two parts - steady, proportional to velocity squared (i.e. usual formula 0.5*CD*S*ro*V^2) and unsteady, proportional to acceleration (CVM*m*dV/dt). So if it's important or not - depends upon acceleration of the particles. It's a good idea to turn it on - turning it off will not give any conciderable speed up of lagrangian calculations.
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