As Grid has evolved since the tutorial was written, there is now an easier
way to create the channel:
Click and create a new grid with
dimension 2.5x0.32 consisting of 12x4 quads.
Choose the "Create Clockwise Circle" mode
and create a circle approximately
at (0.5, 0.2). Place the mouse cursor above the center of the circle and
press Return. If a list of items pops up, choose
the Point in the list. In the dialog box enter the exact coordinates for the
circle center and click Ok. Now move the mouse
cursor atop the circle and press Return once
more. Choose the circle from the list and change the radius to 0.05.
Choose the "Selection" mode
and
make sure inner node and boundary node are selectable
,
.
One by one, select a column of nodes and arrange them on the sides of
the circle. Use the middle mouse button to move the selected points.
Hold Control while doing so to restrict movement to the x-axis. Try to
arrange the nodes around the circle as shown in the image below.
Now select the inner node near the circle center (not the circle center
itself) and choose Delete selected items from the
context menu.
Now we have to put the inner nodes on the circle boundary. Select the
inner nodes near the circle and open the context menu. Choose
Operations/Inner to BoundaryNode
and the channel is complete.