Hello:

I am simulating a unsteady drop (liquid) deformation under zero gravity uniform flow (gas) in Fluent. I am not getting any change in shape of drop. Drop is moving towards downstream direction but no change in shape which is a desirable for this simulation.

I am using -

(In SI Units)

Liquid density=600

liquid viscosity=0.01198

Gas density =1.5

Gas viscosity=0.00029

Gas velocity at inlet = 1.2 m/sec

Duct size= 2cm in X-dir and 1 cm in y-dir

grid : 120 cells in X and 120 in Y dir

Bubble diameter 0.33cm

(Re)liquid=200 (based on drop dia)

(Re)gas=20 (bases on drop dia)

time step=1e-4

Webber number=8 and 40

I ran the case upto 2 seconds.

I am using VOF model with geo-reconstruct option.

Discritization scheme are Presto, Piso and Quick for pressure, pressure-velocity coupling and momentum respectively.

The upper and lower side of duct are periodic. Uniform velocity at inlet and pressure outlet.

Any help or comments will be apriciated...

Thanks in advance.

Ron

hi,

what's the interfacial tension? does your drop moves with same velocity as your gas? If so, I can't see a reason for it to deform. But if you initialize your drop velocity as 0 and the rest as 1.2 cm/s, then I am quite sure that you will have deformation immediately.

Thanks I got the results. Please let me know how to calculate pressure differene across the bubble interface in Fluent.?

Thanks,