We can do several assumptions:
We suppose mass transfert across bubble-air interface
is null. Therefore, the corresponding boundary condition is :
Moreover, the viscosity of water is much more important
than the viscosity of air, it involves :
This means the shear stress vanishes on the air - water
interface.
The definition of the two following numbers allows
to classify the different types of diphasic flows :
For a flow of liquid around a gas particle, we have :
(indeed, it is equal to 0.017)
In order to verify (or not) validity of FLUENT computation,
we use some theorical results.
We can define Reynold's number with following characteristics
:
Hence, we deduce :
with the approximation :
Comment: Contrary to a flow around a solid
sphere, a flow around a spheric bubble don't remove for any Re. We hope
this result will be verified.