Dear Dr. Mathias,

Thanks for your quick response. I think that I find a way to solve the problem but want to double-check with you.

In two compartment Shan-Chen model(oil with rho=0.8 inside the water with rho=1), I try different g. When g is 3.5, the simulation can converged in around 40000 steps (the simulation domain is 100*100*60, the initial oil drop size is 40*40*40, periodic boundary in x and y, the top and bottom is set up to be bounce-back solid wall with a density (0.6 for latticeOil, 0.4 for latticeWater)). I increase g for larger repulsive force because I find that there are significant miscibility if g is 3 or less. When g is 3, the volume of formed droplet tends to decrease with the fixed contact angle and it takes very long time to converge. In that case, if the initial volume of droplet is small, the droplet tends to disappear after many iterations.To be concluded, It is very hard to achieve the mass conservation if g is 3 or less. Choosing g of 3.5 may works for setting up the contact angle in 3D.

Thanks for your response.

Best regards,

Simon