# Research

## Biomimetic morphing and aerodynamic shape control

Principal investigator: | Ranjan VEPA |

(Feedback control of aerofoil section shape in subsonic and transonic flow for UAV, airship & turbo-machine applications, integration of computational aeroelasticity (CFD/CSD) with deforming grids and application to active flow control) Our primary interest in the field of biomimetic morphing and aerodynamic shape control based on smart structures [1] is in the design of shape control systems for the aerospace engineering industry. Control system synthesis for aeroelastic systems incorporating smart structures can be used to design morphing wing sections which are also known to be useful in flying an aircraft through different flight regimes including transonic flow. This in turn leads to an unsteady aerodynamic modelling [2] requirement in the frequency domain. Thus in the case of unsteady flow control applications of smart structures, linearization in the frequency domain is highly desirable. The traditional approach to linearization has been to perturb a steady solution and linearise the equations for the perturbation. In this study an alternate approach of solving the Euler equations is pursued [3]. The unsteady model is harmonically linearised about a quasi-steady solution in order to fully exploit the solution capabilities in steady flow. The applications of this work are to compressor stability and control, flow control over wings and aerofoils which involves the solution of the adjoint Euler equations [4] and the control of biomimetic aerodynamic flows [5, 6]. Novel designs of unmanned aerial vehicles can be traced to the principles governing the locomotion of birds. Applications are to drag reduction and active Tollmien-Schlichting (T-S) wave inhibition in commercial aircraft and to develop energy efficient flow control schemes for future aircraft.

Related Publications:

1) Vepa, R. "Dynamics of Smart Structures", John Wiley, and is in print. ISBN: 978-0-470-69705-4.

2) Vepa, R, “Aeroelastic Analysis of Wing Structures Using Equivalent Plate Models” AIAA J., Vol. 46, No. 5, May 2008, pp 1216-1223.

3) Vepa R.: “Finite-Volume Solution of the Harmonically Linearised Euler Equations for Aeroservoelastic Applications” Paper presented at the CEAS European Air & Space Conference, 26-29 October, 2009, Manchester, UK.

4) Vepa, R., “Optimal boundary flow control: equivalence of adjoint and co-state formulations and solutions” Paper in the Proceedings of the IUTAM Symposium on Flow Control and MEMS, Ed. By Morrison, Jonathan F.; Birch, D. M.; Lavoie, P., Series: IUTAM Book series , Vol. 7 , 2008, ISBN: 978-1-4020-6857-7.

5) Vepa, R., “Biomimetic flight and flow control: learning from the birds”, Paper in the Proceedings of the IUTAM Symposium on Flow Control and MEMS, Ed. By Morrison, Jonathan F.; Birch, D. M.; Lavoie, P., Series: IUTAM Book series, Vol. 7, 2008, ISBN: 978-1-4020-6857-7.

6) Vepa. R. “Biomimetic Robotics: Mechanisms and Control” Cambridge University Press, ISBN: 978-0-521-89594-1.

7) Vepa, R., Towards Biomimetic Morphing of Aircraft Wings: Feedback Control of Aerofoil Section Shape, International Forum of Aeroelasticity & Structural Dynamics June 2013, Bristol, England.