How does DualSPHysics handle the free surface?

Asalih3d · August 2020

Could someone explain it to me, even if shortly and point me in the right direction for ressources?

I know boundaries are using DBC or mDBC, but I actually do not know what is done at free surfaces. In multi-phase simulation I suppose it is handled as a phase interface or something like that.

Kind regards

Asalih3d · August 2020

The reason I find it difficult to understand what actually happens, is that the more I read about it, the only thing I find is that at the free surface, one just applies kernel correction and then everything is ok? Atleast for a mono-phase simulation

Seems kind of easy compared to FVM where you have to use Volume of Fluid methods etc., so I just would like to be sure I actually understand it.

Kind regards

gfourtakas · September 2020

Hi,

Please have a read through the Monaghan papers.

Very quickly and in a simplistic way to get you started:

SPH, and more precisely WCSPH, is quite good at that. At the free surface, your density is (near) equal to the reference density. The equation of state will give you a pressure of P = 0, handy.

Now, all the gradient operators are truncated at the free surface which results in a "small" error. We choose not to correct the SPH operators at the free surface (with the exemption of the density diffusion term). I can live with that.

Thus, you have a pressure (zero), a velocity, a density. etc!

Things are different with FVM. We use Lagrangian particles that move in space. The magic of WCSPH!

Regards,

George

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How does DualSPHysics handle the free surface?

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