Virtual mass force?

bk

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?