How t o define head loss coefficient?pls urgent.

mitesh

I want to define darcy's friction factor in fluent?How t odefine it?Head loss=f*l*V^2/2gd.In this i want to define f.?second thing is that what is its relation wit hlinear and quadratic resistances in subdomain sources.Pls anybody knows then tell me.

linear resistence =CR1=m/Kperm.

CR2=Kloss*density/K. Here Kperm is permeabilty coefficient.how to define this?suppose any obstruction takes 20 percent volume then is it .20.is this right or not? and what is Kloss.is it related to friction factor? I also want to know that is 2D blcoakge possible or not in fluent?.Pls help me. Thanking you all.