Learning Forum

[SR786]

Hi,

I am modelling a mixing tank which is filled with water and air, where a vortex will form due to the motion of the stirrer acting on the liquid as air gets sucked into the centre of the tank whilst water gets pushed up along the tank walls. In order to capture the free surface between air & water, I am using a homogeneous VOF solver. I have read some online material and done the following to ensure solution stability

• Set primary phase as air, secondary phase as water.
• Set operating density equal to the lightest phase, air (1.225 kg/m^3)
• Model surface tension coefficient between air & water as 0.072 N/m
• Activate implicit body force

When it comes to initalising the solution, there is an option for water volume fraction where the default number is zero. Should I leave this value as zero or do I need to change this value?

[Rob]

The button you're looking for is Patch. So, initialise the domain to "something" and patch the other phase in. 

[SR786]

Okay no worries, so I should ignore this box then?

[Rob]

No, that's the initial value. You then patch the new one onto that. So I'd initialise the domain to one phase or the other and then patch part of the region to the phase I want there. Check the dam break tutorial/example out (it's in Fluent's Help system).