hello Everyone I have a simple CFD problem. But i am just a begginer in this field. It is a diffusion-convection problem. consider a series of injector (In) on y axis and a a uniform V flow coming from the infinite. and I have to solve the unsteady diffusion-convection equation within the rectangular domain ABCD. all the injectors have the same length b. and AB cross the middle of In, and CD cross the middle of the distance between In and In+1. on the section AD we have the entry condition =0 except on the injector which is Co. on sections AB and CD we have a symetric condition. on section CB we have outlet condition. my problem is that I do not know how to know the expression of the boundary condition on AB,CD and DB. Thank you for your helps.

a scheme description

In-2

------->

V

In-1

V -------> A B

In-------------------------- | |

| |

D -------------------------- C ----------------------------------> x

In+1

V ------->

In+2

the right scheme: -----------------

V ----->

In-1 V ----->

B In---------------------/ A

/ /

/ /

D /----------------------/ C V ----->

In+1