In terms of biomimicry, our first example concerns shark skin, which gives industrialists ideas for making more efficient tires or boat hulls. And success is sometimes there.
franceinfo: How does shark skin make it possible to make objects such as boat hulls or tires?
Anne-Laure Dagnet: This jewel of hydrodynamics allowed a tire manufacturer to develop a model that performs very well in the rain to manufacture the Rainsport 3 tire, Uniroyal engineers analyzed the interactions between water and the skin of sharks and they drew a drawing.
Basically, there are two big grooves in the center like two big boulevards. On the left, smaller almost perpendicular streets, and on the right, large arteries that start at an angle. These different channels make it possible to evacuate the water as well as possible, and to avoid aquaplanning. Tests carried out on the road have demonstrated the effectiveness of the process, on wet ground braking is shortened by 8% compared to other tire models.
How engineers in the automotive sector were inspired by the shark?
Looking at his skin with a magnifying glass, they saw that he was covered with scales, in fact they are tiny teeth that pierce the epidermis; they are placed like tiles on a roof, and this is what helps to reduce drag when the shark is swimming. The water is directed towards the grooves and evacuates, it is thanks to these scales that it goes very quickly, you have undoubtedly already seen impressive images of a shark which swims quietly, and which suddenly melts on its prey with lightning speed. Thanks to this very special skin, the mako shark or shortfin mako shark, the fastest in the world, can exceed 80km/h.
Have other manufacturers been inspired by shark skin?
Yes and some would like to use its hydrodynamic and aerodynamic qualities to improve the performance of airplanes, wind turbines, drones, cars, diving suits or boat hulls
with uneven success. Airbus tried to integrate ribs on its aircraft cabins, so it reduced friction by about 8% but the weight of this coating canceled out this beneficial effect.
Boat manufacturers would like to improve the glide of the hulls to reduce fuel consumption. Incidentally, it would keep the hull of the boat clean, preventing parasites from attaching themselves to it, but for the moment the process is not perfected. On the other hand, it was such a success on ribbed swimming suits that these swimsuits were banned from competitions, too efficient, disloyal compared to competitors.