credit: NASA Marshall Space Flight Center / Caption: click on the image to see a larger version
NASA says, "This schlieren photo depicts a wind tunnel test demonstrating air flow over the .331 percent model of the Ares V heavy cargo launch vehicle at Mach 4.5. Schlieren imaging is a diagnostic method used to visualize air flows with varying densities.
It is widely used in aeronautical engineering to photograph the flow of air around objects. Marshall [Space Flight Center] engineers are testing the stainless steel and aluminum model to collect aerodynamic data that will help the Ares V team determine basic requirements for guidance, navigation and control of the Ares V vehicle."