The Evaluate_Gradient_Cells_Ortho_Diffusion procedure evaluates the gradient of Phi at the cell centers using the specified Ortho_Diffusion Term. The gradient is not necessarily constant across a face, since the diffusion coefficient may change, but the flux is. This procedure calculates the constant flux across a face, then divides by the diffusion coefficient of the cell to get the gradient at each face. Then, averaging opposite faces results in a cell-centered gradient.
|call Evaluate_Gradient_Cells (Diff_Term, Phi_MV, Grad_Cells)|
|Diff_Term||The Ortho_Diffusion Term to be evaluated.|
|Phi_MV||The Phi Mathematic Vector to use in the evaluation.|
|Grad_Cells||The gradient of Phi vector evaluated at the cell centers.|
|Grad_dot_N_Faces_of_Cells||The gradient of Phi dotted with the unit normal at each face of each cell.|
The Evaluate_Gradient_Cells_Ortho_Diffusion code listing contains additional documentation.
Michael L. Hall