Selection of relaxation time tau_f in LBM_3D_SinglePhase_Solver.py

[gxw-ll]

Hello, Professor! I have encountered a problem with the example you provided in img_ftb1131.txt. The file LBM_3D_SinglePhase_Solver.py provides two tau_f. when I use the self.tau_f=3.0*self.niu+0.5 The permeability results are as follows： when I use the self.tau_f=self.niu/3.0+0.5 The permeability results are as follows：