As the row over Mercedes’ Super DRS drags on (!) we thought it useful to take a look at the way in which nanotechnology is helping Formula 1 cars slip through the air more efficiently. Without giving too much away, we can reveal that anyone taking a profilometer or atomic force microscope to the surface of the cars from at least two teams would find evidence of nanoscale biomimetic structures.
On the macro scale, conventional wisdom seems to dictate that the more ‘slippery’ you want to make something, the smoother it should be. But as we so often find, once we get down the scale of a few tens of nanometers the world looks very different. The reason that a variety of natural structures can exhibit remarkable properties, a gecko sticking to a ceiling or lotus leaves remaining perfectly clean is all due to nanoscale effects. Many of the structures we imagine to be smooth are anything but when viewed through an electron microscope.
This is especially important for sharks, whose aerodynamic shape is partly as a result of their poorly developed muscles for active breathing. Water needs to constantly moved across the gills, and as a result most sharks need to be constantly in motion. Being streamlined on the macro scale helps, but sharks have a few nanotech tricks that they have evolved, ones that are now being copied by engineers working in motorsport.
The general term for this is biomimetics, i.e. copying nature.
To quote Dr David Birch from the Fluids & Vehicles Research Laboratory at the University of Surrey:
A substantial proportion of the drag penalty incurred by a number of vehicles (including aircraft, submarines and surface vessels) is due to skin friction, and the magnitude of the drag is strongly related to the local state of the turbulent boundary layer over the surface of the vehicle. A number of recent simulations have demonstrated that a ‘smart’ surface capable of sensing and reacting to local flow conditions could reduce skin friction drag substantially.
A couple of typical academic publications, Biomimetic structures for fluid drag reduction in laminar and turbulent flows and Drag reduction in Stokes flows over spheres with nanostructured super hydrophilic surfaces are available for those wanting to explore the subject in more detail.
But this isn’t just an academic exercise. Already a number of companies have been producing nano structured coatings, mimicking the nanoscale roughness of sharkskin, and applying them to ships, submarines and aircraft, as this video from EasyJet shows.
The trick is also being copied by a number of Formula 1 teams, although the challenge of keeping the surface coatings active when being pelted by tyre debris, dust and a content stream of nanoparticles being emitted from the exhaust system of the car in front (more about that what that happens and what advantage it gives another time) may limit their use to specific areas of the car.