I know how to draw vertical sections along the
grid line but how to make picture of diagonal
section between two points for instance between
(5,5) and (15,25).
I don't have a complete answer, but if you can
generate a set of points forming the diagonal, you can
accomplish what you need, by using the function samplexy
.
The second question is how to do the same
diagonal section of velocity perpendicular to this
section having only components of velocity along
axis
Because you know the angle of the diagonal line, you
can compute the component of velocity perpendicular to
the line by
let vn = (-1)*u*sin(angle) + v*cos(angle)
Once you have computed the normal component of the
velocity like this, you can again use the samplexy
function to get the slice of the velocity field along
the line.