Grid file format

<No of points>   <No of triangles>   <No of boundary edges>
1    x1    y1
.    .     .
.    .     .
.    .     .
.    .     .
1    a1    b1   c1
.    .     .    .
.    .     .    .
.    .     .    .
.    .     .    .
.    .     .    .
1    a1    b1   typ1
.    .     .    .
.    .     .    .
.    .     .    .

Node numbering starts from one (fortran style)

In each triangle, the nodes (a1,b1,c1) are ordered counter-clockwise.

For each boundary edge, when you move from node a1 to node b1, the computational domain lies to your left.

Boundary edge types:

Solid wall = 3
farfield   = 5