Problem with lift force coefficient

summer

Hello, Dear All,

I am using Eulerian multiphase model to simulate gas-liquid two-phase flow in a verticle pipe (Let "z" as the axial direction). I set the lift force coefficient to be 0.1 in phase interaction; however, when I tried to monitor the lift force, I found that it was 0.005, and 0.2635 in x and y direction, respectively, which were kept as contant finally. I do not quite understand it. Any commments are welcome. I appreciate for your help.