Include Air in the simulation

kevinxmu

How can we include air in the simulation? For example, if we want to consider the air lift of a floating body. Is this can be done?

Do I need to create two fluids (one for air, another for water) and one floating body in the tool? For the most example cases such as sloshing, why there is no air defined?

Asalih3d

You have to do a multi-phase simulation to include air, since in single phase the pressure equation is only valid for liquids and not gasses. In the multi-phase simulation you can specify a single fluid (like air) for your simulation. To do this you have to spend some time inside the multi-phase documentation and examples.

I would assume that in sloshing case, since the air has a density which 1/1000 of water it can be done with only water. You can always include it, if you want.

Kind regards

kevinxmu

Thanks @ Asalih3d , do you know whether this can be done in ver 4.2 or it has to be done through earlier version DualSPHysics4.0_LiquidGas.exe?

Asalih3d

You have to go into examples folder and find the multi-phase examples and run through them and the documentation to get the best overview of possibilities and setup.

Kind regards

James

I think Ver 4.2 should include the multi-phase functions.

bladomas1

@ Kevin, The DualSPHysics package v4.2 contains DualSPHysics4.0_LiquidGas.exe, this is the latest public/stable version. The numbering might be confusing, but everything is in order.

kevinxmu

@bladomas1 Thanks. Just to double confirm- I can use the DSPH 4.2 exe for Liquid-Gas analysis and ignore the DualSPHysics4.0_LiquidGas.exe in the pacage, is this correct?

bladomas1

No, use DualSPHysics4.0_LiquidGas.exe for Liquid-Gas. If you work single phase only then use DSPH 4.2 exe.

Edit: Follow the example .xml file. Or even read the manual for DualSPH 4.0 LiquidGas. The setup is a bit different. The .sh /.bat file is very similar, only the compute part uses a different command (different solver).