[huyidao]

I want to solve this equation ,in which U, a and Q are already known. In the equation there is only a convection term. I use this to calculate the distribution of C in a pipe, it has a special boundary condition C(r=inlet)=b*C(r=outlet),of which b is a constant.
My code is:

fvm::div(phi,C)+fvm::Sp(a,C)=Q

My question:
1:Is there a boundary condition C(r=inlet)=b*C(r=outlet) in openFoam?
2: If not, I plan to solve this equation iteratively. First, assume C(r=inlet)=0,then the C(r=outlet) is calculated, then the C(r=inlet) is calculated by C(r=inlet) =b*C(r=outlet),do it until converges. Because according to my knowledge, this is a hyperbolic equation which means it can be solved only by the inlet condition, but in openFoam all the boundary must be given a boundary condition. Then what boundary condition should I define at the outlet of the pipe?
Can anyone give me some advice?
Thank you.