The reason for the noise in aircraft is not only due to the jet engines but also because of the behavior of the air as it travels over the wing and the fuselage surfaces. This is astonishing when we compare this to a bird flying over our head gliding almost
silently. The secret lies in how it manipulates the airflow over their wings. It does so by using the little serrations in their feathers.
Studies have been taken up to investigate the separation concept. This has been put in turbine blades and wing geometries. This has shown to augment the aerodynamic efficiency. The nature of airflow from the front to rear and the top and bottom surface is modified. An analogy can be drawn at this stage if we consider the air as if it’s a quiet ocean rushing up over a beach. The waves which are more smaller creates lesser sound and similarly, due to these serrations, the noise is further reduced in an aircraft.
Airbus is exploring the serration technology for developing a silent aircraft. Efforts are also underway to use honeycomb as a structural material as it is tremendously sturdy for its mass and has been employed in reducing the weight of aircraft.
Bats use a form of stretchable wing which is extremely strong on the stretch axis. Research groups has identified this tremendously powerful enabling technology where the wing can be used in its compressed state and expanded state at the same time, it, the adaptable wing can be used for both agile and highly efficient cruise configuration. NASA has been working on a morphing wing aircraft and the breakthroughs with honeycomb structure is likely going to accelerate concepts like these into reality.
The dragonfly wing uses a distribution of vanes and the types of hinges interconnecting them to give them immense flexibility in flight. Genetic algorithm backed optimisation technique on the computer generated wing configuration to bring out the shape of the wing has also been proposed. The genetic algorithms been employed into. Boeing has a concept of blended wing body and it’s benefited from the genetic algorithms in reducing the weight of the aircraft by optimizing the skin of the wing itself.
So, nature has conquered the concept of flight in a vast variety of forms. We, as humans are striving to achieve the same. There are hidden patterns and signals from nature to strive further in the effort to perfect the art of flight in the future to come.