Tutorial 2: Idealized Wing-Body

Create two ellipses, and a surrounding rectangle as shown below. You can either create 4 poly-line segments, or create a rectangle, and use the "Split Rectangle" button to split it into 4 pieces.

Create corners surrounding the geometry and assign them as shown. Assign 2 corners to each respective segment of the outer box. Note that there should be 2 corners which are assigned to both the "Body" and the "Wing".

Assign these corners to the "Body"

Assign these corners to the "Wing"

Use the "Insert Corners" button and the "Place Corners" button to create corners, then link them to create a box at the intersection of the surfaces, as shown below.

Create a "Wrap" around the rest of the ellipses by placing corners radially outward from the existing corners around the surface, then linking them, as shown below.

Insert corners on the outer edges then link them to the topology in the center. In this case, this must be done in two steps, as shown below.

Link corners, then insert corners on the links in the marked locations

Complete the topology by linking the newly inserted corners as shown below, then generate the grid

The grid can be loaded and reloaded while it is being generated, by pressing the refresh button. The resulting grid is shown below.

Clustering can be applied to the grid near the surfaces to increase density on the boundary layer by selecting the surface then pressing the "Surface Properties" button . Spacing is the initial spacing of the cell bordering the surface, and stretch is the multiplier of spacing for every cell farther away from the surface.

Apply a spacing of "1e-4", and stretch of "1.2" to both the "Body" and the "Wing".

Stop grid generation if it is still running (this can be done by pressing ctrl-c with the grid generation window open), then generate the grid again.

This is the resulting grid, after it has completed. Notice the increased cell density around the ellipses

This is a close-up of the surface intersection.

Note:

You may try to create a wrap around the surfaces without a block at the surface intersection, as shown below. Although it is possible to generate a grid on this topology, it will result in a poor-quality grid.

When a grid is generated from this topology, the cells at this surface intersection will be highly skewed, because two blocks are being forced to share a small angle. The problem grid is shown below. Notice how skewed the highlighted cell is.

To correct this problem, delete links and insert corners, as shown below.

Link the corners to create a single block at the intersection of the surfaces.

The resulting grid at the surface intersection is shown below. Note the grid lines improved orthogonality to the surfaces.