Some monotonic difference schemes for convection-diffusion equations

With the varieties of the cell Reynolds number, the properties of the upwind scheme, the Samarskii Scheme and the modified Dennis scheme for convection-diffusion equations are analysed. Three semi-implicit schemes which are unconditionally stable and monotonic are present by those schemes. Numerical tests have shown these semi-implicit schemes can be applied to the solution for the steady fluid flow problems of high Reynolds