Research Associate

Education

  • Ph.D Aeronautical Engineering, Imperial College London
  • MSc Thermal Power, Cranfield University
  • MSc Aerospace Engineering, Universita degli Studi di Padova

Current Research

Project Title: Aeromechanics of Actuated Membrane Wings

Academic supervisor: Rafael Palacios
Sponsors: EPSRC, EOARD. 

Membrane wings offer the potential for better aerodynamic performance than fixed wings because of their ability to delay stall and to allow for better manoeuvrability of the vehicle. This is the reason why they represent an interesting solution for Micro Air Vehicles. The resulting performance could be additionally increased with an active control of the wing, that can be achieved, for example, embedding the membrane with electroactive polymers.

The aim of the project is to develop a numerical model for the aeroelastic problem of the actuated membrane. The primary scope of the model is the evaluation of the dynamic performance of the membrane wing and how these can be improved with embedded actuation.  This aeroelastic framework has shown to be suitable for capturing the strong fluid-structure interaction of the unsteady low-Reynolds number flows around dielectric elastomer membrane wings. For details on the numerical framework see our article here.

Effect of membrane compliance

The high-fidelity model allows the investigation of wing desing parameters, like the prestretch, which influence the way the structure and the fluid interact. Fig. 1a and 1b show the vorticity contour plots around a membrane wing for compliant and very stiff conditions . Larger prestretch values determine a stiffer structure, with smaller deformations and a faster shedding of vortices.


Fig. 1a - Membrane wing,  prestretch = 1.02Fig. 1b - Membrane wing,  prestretch = 2.0
 
Vorticity contour for a DE hyperelastic membrane wing, Re = 2500, alfa = 8deg, prestretch = 1.02
 
Membrane wing, lambda = 2.0
Vorticity contour for Re = 2500, α = 8°.  Membrane material : VHB4905. 
Summary of the table's contents

 

Effect of material modelling assumptions

Rate-depentent effects can play a major contribution into the dynamics of dielectric elastomers. The aeroelasitc model has been used to asses their impact into the final aeroelastic response of the system. The main findings show that rate-dependent effects can significantly alter the dynamic response of the wing. Fig. 2a and 2b compares the unsteady flow response around DE membranes under hyperelastic and viscoelastic material assumptions. 


Fig. 2a - Membrane wing,  prestretch = 1.02,
hyperelastic constitutive model
Fig. 2b - Membrane wing,  prestretch = 1.02
viscoelastic constitutive model
 
Vorticity contour for a DE hyperelastic membrane wing, Re = 2500, alfa = 8deg, prestretch = 1.02
Vorticity contour for a DE viscoelastic membrane wing, Re = 2500, alfa = 8deg, prestretch = 1.02 
Vorticity contour for Re = 2500, α = 8°.  Membrane material: VHB4905.
Summary of the table's contents

 

Effect of integral actuation on system dynamics

The model has been used to assess the authority of integral actuation through embedded dielectric elastomers as membrane wing material. Fig. 3 shows the time evolution of lift and drag coefficients (red and green, respectively),  maximum membrane amplitude (blue) for an harmonic input of the voltage (black line). The time evolutions are normalised with their maximum values. The figure also shows the vorticity evolution around the actuated wing. As a results of the integral actuation, the membrane shows an increase of 10% of the mean lift-to-drag ratio. Numerical results for both the hyperelastic and viscoelastic material assumptions found good coorrelation with the experimental results in the literature. Click here for more results

Fig. 3 Integral actuation of membrane wing - 4 Hz
 
Actuation of DE membrane wing 4Hz
Vorticity contour for Re = 2500, α =4° and integral actuation.  Membrane material: VHB4905.
Summary of the table's contents

‌The aeroelastic model allows to capture the different flow structures that are generated by different actuation frequencies and voltages. Fig. 4a and 4b shows the vorticity field around the wing actuated with voltage signals at 6 Hz and 8 Hz, respectively. The flow structures are significantly different from the ones in Fig. 3 due to the interaction of the fluid with higher membrane modes. The final performance, in terms of variation of the mean lift coefficient, are shown in Fig.5. 

Fig. 4a - Actuation at 6 HzFig. 4b - Actuation at 8 Hz
 Actuation 6 Hz  Actuation 8 Hz
Vorticity contour for Re = 2500, α =4° and integral actuation.  Membrane material: VHB4905.
Summary of the table's contents
 We are also working on the identification of suitable control techniques for the aeroelastic system. For more information check our work here.

Publications

PhD dissertation

Buoso, S. (2016) "High-fidelity modelling and feedback control of bio-inspired membrane wings", Ph.D dissertation, Department of Aeronautics, Imperial College London. Download from Spiral

Journal papers

Buoso, S. and Palacios, R., (2016) "Viscoelastic effects in the aeromechanics of actuated elastomeric membrane wings", Journal of Fluids and Structures 63, 40-56. Open access link.

Buoso, S. and Palacios, R., (2015) "Electro-aeromechanical modelling of actuated membrane wings", Journal of Fluids and Structures 58, 188-202. Open access link.

Conference contributions

Buoso, S. and Palacios, R., "High-fidelity simulation and reduced-order modeling of integrally-actuated membrane wings with feedback control", SPIE 9799-82, Active and Passive Smart Structures and Integrated Systems X at the Smart Structures and Materials/NDE, Las Vegas, Nevada, 20-24 March 2016.

Buoso, S. and Palacios, R., "Feedback control of integrally actuated membrane wings: a computational study", AIAA 2016-0714, 57th AIAA/ASCEA/AHS/ASC Structures, Structural Dynamics, and Materials Conference at SciTech, San Diego, California, 4-8 January 2016. Download from Spiral

Buoso, S. and Palacios, R., "Reduced-order modelling and feedback control of integrally actuated membrane wings", IFASD-2015-072, International Forum of Aeroelasticity and Structural Dynamics, St. Petersburg, 2015. Download from Spiral

Buoso, S. and Palacios, R., "Electro-aeromechanical modelling and feedback control of actuated membrane wings", AIAA 2015-0267,  23rd AIAA/AHS Adaptive Structures Conference at SciTech, Kissimmee, Florida, 5-9 January 2015. Download from Spiral

Buoso, S. and Palacios, R., "A nonlinear viscoelastic model for electroactive inflated membranes", 11th World Congress on Computational Mechanics, WCCM XI, Barcelona, 20-25 July 2014. Download

Contact

Department of Aeronautics, Imperial College London
Room 363, Roderic Hill Building
South Kensington Campus
Prince Consort Road,
London SW7 2AZ, UK

Tel: +44 (0)77 605 09511
E-mail: s.buoso12@imperial.ac.uk

Last updated: March 2016