how to calculate surface tension

dear all

i simulated the two liquid droplets coalescence in air using single-phase model(BY Xiu qing Xing,Simulation of droplet formation and coalescence using lattice Boltzmann-based single-phase model),

and i have some results.but now i don’t know how to calculate the surface tension .in LBM,we have p=cscsrho,and according to Laplace equation :(p1-p2)R=2Q

where p1 is the the liquid pressure of liquid droplet interface.p2 is the the air pressure of liquid droplet interface . p1-p2 is the pressure difference of liquid droplet interface . R is the radius of the liquid .Q is the surface tension. i find somgthing is wrong with this method to calculate the surface tension. the rusults of surface tention is not right.
so is there other method to calculate calculate surface tension or relevant papers?

thank you in advance.


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You should take a look at “Lattice Boltzmann Modeling: An introduction for Geoscientists and Engineers” by Sukop. First of all Laplace’s equation states that Delta P = sigma/r and not 2sigma/r. Are you sure your conversion from lattice units to physical units is correct? Unfortunately I do not know of other methods of determining the surface tension. Possibly the wetting effect and droplet angle formation at boundaries but this is also based on the Young-Laplace equation.

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