One of the powerful abilities of computational fluid dynamics is that it can allow us to visualize the usually invisible movement of a fluid past an object. This understanding can be critical in improving the designs of vehicles and aircraft.

In this lesson we'll use a range of different visualization tools in Luminary to analyze the movement of air around the Piper Cherokee.

Before continuing, first ensure the airplane is clearly visible in the 3D Viewer, and turn off and deselect any other existing visualizations.‍

We'll create two slices, one running vertically through the length of the Piper Cherokee and the other cutting vertically across the wingspan:

Now experiment with turning these slices on and off (using the eye symbol to the right of each in the Visualization section of the Control panel), and changing their Display options to view the different velocity magnitudes. This should allow you to get a general idea of how the air is moving around the airplane, although you will not see exact flow features.

Next we'll create streamlines to highlight how fluid particles are moving through the domain around the aircraft. We'll seed a rake beginning from just in front of the aircraft. Given the wings have a slight V-shape upwards, some of these streamlines will pass above the wings, and some below.

First turn off and deselect any previously created visualizations. Then:

You should see that the streamlines nearer the root of the wings pass over the top of the wings and then under the tail. Streamlines closer to the tip of the wings begin to spiral around as the air passes backwards from the airplane. Try experimenting with changing the streamline settings to get further understanding about the flow movement.

Now we'll add vectors into to the domain to show the instantaneous movement of fluid particles. First turn off and deselect any previously created visualizations. Then:

You will notice that in areas of high mesh density, i.e., around the airplane, there is a greater number of vector glyphs. Additionally, the vectors move generally in the direction from the front to the back of the plane, but close to the surface itself the flow changes direction as it avoids the airplane. Depending on the exact seeding, you may also discover areas of recirculation.

Finally we'll create a representation of fluid movement across the surface of the Piper Cherokee using a technique called surface line integral convolution (surface LIC). This is a method for visualizing vector fields.

First turn off and deselect any previously created visualizations. Then:

While this visualization will not show the velocity of the flow at the airplane surface (which is zero in this case), it can show an idea of the flow near the wall by illustrating the directions of the stresses there.