This animation compares the use of a static vs. moving aero-dynamic device to control of vortex structures behind an Ahmed body.
The lower two cases show quick response of vortex structures to the moving device, leading to future development of real-time flow control in car driving.
FieldView animation courtesy of Dr. Ken-ichi Abe, Professor, Dept. Aero. & Astro., Kyushu Univ.