hi,there,

obtaining the difference representatives of the space derivatives near wall is too much trouble,because I use central difference and staggered grids for the viscosity terms,there are two u(parabell to the wall) points outside the wall(the same as the upwind scheme),but I can only use one ghost point,how to deal with the space derivatives near wall?please give me some help

thanks

(1). You will have to follow the existing approach first in developing the numerical formulation. (2). Pick some books and technical papers first, and try to follow their approach to write your code. Algorithm development is quite involved, and this includes the boundary condition formulation. (3). At the wall, there will be boundary layers, turbulent boundary layer is more likely. So, you need a thorough understanding of the current methods before you can start writing the code.

please give me a general discription about it,it's not a easy way to find some technical paper on this question,thank you

Look for the book numerical heat transfer from Patankar. The use of the staggered grid is very explained.