For anyone who’s ever heard a helicopter fly by they know the sound has a signature all its own. As a heli’s blades spin a high pitched chopping peaks above a low whipping cycle, literally making a helicopter appear as if it move to the beat of its own drum.
While the science surrounding a helicopter’s signature sound has been understood for quite a while, the phenomenon that produces it has, until now, been impossible to capture visually.
In a newly published research project Markus Raffel of the German Aerospace Center in Göttingen has created a technique to take photos of the sound generating vortices that form around the end of helicopter blades.
Using a method that leverages the same effect we observe when air waves across the surface of a hot road, Raffel images light as it bends through the inconsistent densities of air that exist around and inside helicopter blade vortices.
Although Raffels research has produced some stunning images the goal wasn’t to create art. Through his research the German physicists hopes to make helicopters less prone to vibration, and ironically, a bit quieter.
Image Courtesy of DLR