This course aims to provide the bases for the physical understanding and the mathematical representation of the main phenomena originating from the interaction of a flow and a flexible structure, both in static and (particularly) in dynamic conditions. In consideration of the importance of the dynamic aspects of aero-elasticity a relevant number of lectures is dedicated to the fundamentals of theoretical unsteady aerodynamics.

Ability to interpret a system constituted by a flexible structure and a flow in terms of a unit whose mechanical properties are different as those of its individual components. Ability to perform qualitative estimations of the critical speeds and knowledge of the most important solutions adopted to remove dangerous situations.

Differential and integral equations, basic knowledge of aircraft structures and steady theoretical aerodynamics.

Definition of aero-elasticity and classification of aero-elastic phenomena. Galloping and vortex shedding in aeronautical and non-aeronautical structures. Reminder on the elastic and mechanical properties of wings and fuselages. Differential and integral equations for the static and dynamic equilibrium.
Static aero-elastic problems: torsion divergence and aileron reversal in a wing section and in wings of moderate and high aspect-ratio; effect of the wing sweep; lift distribution on a twisted wing; efficacy loss of the ailerons. Bending divergence in slender fuselages, space launchers and flexible pipes.
General equations for the unsteady motion of an ideal fluid. Incompressible flow fields: accelerated motions and importance of the reference frame. Virtual mass forces. Flat plates, thin airfoils, wings and slender bodies subject to general or harmonic displacements in a uniform stream. Phase relations between displacements and aerodynamic forces. Unsteady compressible flows. Fundamental field solutions in a fluid at rest and at high speed. Harmonic motion of airfoils and wing in a compressible stream.
Problems of dynamic aero-elastic response. Aero-elastic transfer functions. Classical flutter: equations and solution approaches for a wing profile. Parametric analysis and flutter prevention criteria. Effects of the compressibility and of the flight altitude. Stall flutter and panel flutter. Whirl-flutter in large rotors mounted on V-STOL aircrafts and wind generators. Buffeting, buzz and transonic buffeting phenomena.

Exercises are developed in the computing laboratories by exploiting codes provided by the teachers in order to analyse typical aircraft configurations. More in detail, exercises include:
- Fundamentals of Finite Element formulations in aero-elastic problems.
- Explicit computation of stiffness and damping matrices in wings.
- Computation of bending and torsion oscillation modes in classical wings.
- Prediction of static aero-elastic responses.
- Prediction of the aero-elastic divergence in wings made of metal and composite material.
- Prediction of the dynamic aero-elastic response and flutter on the same wings as above.
- Elements of Vortex Lattice and Doublet Lattice methods and their use in predicting divergence and flutter.

a) Reference book:
G. Chiocchia, Principi di aeroelasticitą, Levrotto & Bella, Torino 2002
G. Chiocchia, Lezioni di aerodinamica instazionaria (To be discharged from the course website. Hard copies can be purchased at the Student Press Centre of Politecnico)
b) For a deeper knowledge:
E.H. Dowell, H.C. Curtiss Jr, R.H. Scanlan, F. Sisto, A modern course in aeroelasticity, Kluwer Academic Press, 3rd ed., 1995

The final assessment consists in an oral examination including two or three questions posed to the student, possibly expanded through a discussion lasting about twenty minutes. Special importance is attributed to the acquisition by the student of a sufficient level of understanding of the interaction processes between fluid and structure and their related implications.