hi all, I am trying to solve convection-diffusion-reactions(in time and one space coordinate) equations with NDSolve. Most of the time I am not getting solution to my problem as solver fails to converge. I guess the problem is very stiff and convection dominated. When I use upwind difference scheme in fortran, I get the solution easily. How can use upwind in NDSolve? What is the method mathematica uses to solve pdes? any comments are welcome. Thanks in advance.