[risktaker5]

Hello Everyone,
I am doing my project work in sand particle interaction using SedFoam. First I have to do the validation of 2D Pipeline Scouring Case. In that case which i given in the sedfoam tutorials, I am not able to understand how the alpha.a file has been setup specially the equation:

alpha_a[i] = 0.6128*0.5*(1.0+tanh((3+y)*2000))+1e-100;

field[faceI] = 0.6128*0.5
*(1.0+tanh((3+Cf[faceI].y())*5000))
+1e-100;

The equations are from the 0_org directory and is in the alpha_a file. I need the help in understanding the meaning of each and every value which is there in the equation. Please help in the same.