Momentum Exchange Algorithm using Shan & Chen model

Hello everyone,

I’m developing a code using the multi-component Shan & Chen model to perform multiphase simulations and I’m using the Momentum Exchange Algorithm to evaluate the forces at the boundaries (see for more information). I’ve run some test considering disks and spheres submersed in a fluid in order to test that total forces of the fluid applied on a static object are zero when there is no gravity or any other external force. Results came right, thus I decided to extend my tests to multiphase flows. I tried to compare the forces resulting in a capillary bridge and the capillary forces on a plate partially immersed in a fluid.

See Figure of capillary bridge and domain where the forces are evaluated:

The numerical forces I have obtained have an error of around 50-60% respect to the analytical values. I think the error is due to the thickness of the interface and how to deal with it (see next figure, which is a slice of the capillary bridge, it’s the middle cross-section). This figure shows that points inside the white line (sphere/grain nodes) are solid nodes. However, due to the thickness of the interface I don’t really know where the momentum exchange algorithm should take place. Do you have any ideas how to have more precision and better results using the Momentum Exchange Algorithm ?Thanks!