51	Nx+1   - number of points in the x direction, MUST BE ODD
        17	Ny+1   - number of points in the y direction, MUST BE ODD
   0.02000	y_t    - throat height normalized by duct length
   0.00000	sf_x   - stretching factor in x; 0 uniform, ->1 highly clustered
   0.00000	sf_y   - stretching factor in y; 0 uniform, ->1 highly clustered
   1.0E-08      tol    - convergence tolerance