The pictures below show the streamlines for the CFD "virtual wind tunnel" simulation of a Kyosho Mini-Z MR03 Mazda 787b 3D model, "racing" at 10 m/s (36 km/h).
In this type of simulation a streamline is the theoretical path that a particle flowing around the vehicle would describe.
There are five different pictures, one for each of the following rear wing configurations: no wing, flat wing, 45 degree wing, gurney flap, scoop wing.
Both the car and lines are colored according to the air speed. Red represents high air speed (11 m/s) and blue represents low air speed (5 m/s).
No Wing - Air Speed
Flat Wing - Air Speed
45 Degree Wing - Air Speed