Wing design for aerospace vehicles is a compromise between stability and performance. Depending on the intended flight regime of operation, design parameters for wings are chosen. Thus, the wing for a particular flight condition will not remain optimal in another flight regime.
However, birds do not conform to these engineering design laws, as they have the capability to change their shapes by ‘morphing’ their wings, tail, and external shape to suit different flying conditions. Birds appear to adapt to flight configurations that are inherently highly unstable and which further require rapid sensory feedback for their flight corrections and stability.
At times, birds glide through the air without even moving their wings and have large endurance. These have interested researchers in fluid, structural, and control mechanics in this multi-disciplinary optimization field to investigate how birds use ‘wing morphing’ to control their flight.
“Since the Wright Flyer, researchers in the aerospace industry relentlessly strived to develop flight vehicles with morphing wings that can control flight as birds adapt in their flight.”
The art of bird flight would give answers to many problems in the aerospace industry that exist today, viz. maximization of range, endurance; low noise; use of the same vehicle for multi-operation missions; towards a greener air. In fluid mechanics, one of the ways of investigating this phenomenon is by creating Computational Fluid Dynamics (CFD) models based on these morphing geometries. These models can further be used to study the aerodynamic behavior and stability of different wing configurations adopted by birds and look at how changes in geometry are used for control. Validation of the results and actual realization of the ‘morphing wing’ also needs to be considered from a practical point of view.