Translating surface energy to interaction potential (Shan-Chen Multicomponent)

Hi again,

I have written a program using the Shan-Chen multicomponent coupling in openLB with the aim to simulate the flow of water in a domain filled with air. The program is at a point where the geometry and conditions are acceptable, it is however not physically meaningful yet. One issue that i have been unable to find explanation on is how the interaction potential, G, for the two fluids is defined. Is it simply a ratio of surface tensions? or is it more complicated than this.

Some literature on the subject would be useful, I have read the paper “Lattice Boltzmann model for simulating flows with multiple phases and components” by Shan and Chen, but still cannot see a method by which to choose the interaction potential based on two fluids.


Sukop’s book is a good place to start with the quite difficult topic of understanding units in a multi-phase fluid.


Just discovered that book, seems like it will be very useful. For those interested it seems to me that surface tension must be measured for your lattice boltzmann fluid, and then parameters adjusted if the surface tension does not meet your requirements.

Thought id add this here rather then making a new thread.

Ive been playing with a multicomponent model to measure the surface tension of my LB fluid, in order to come up with some valid parameters for a more complex situation. I can control the contact angle of the drop by varying the fluid density at the wall nodes, this does not however give me much confidence that the fluid will behave in the appropriate manner (the model is simply a drop of fluid surrounded by another fluid). What I need is a method by which I can determine what G, the interaction potential, would be for each fluid. I’m using openLB, and the documentation doesnt really extend to this type of model