Design of morphing wing for aerodynamic performance considering the wing flexibility effects
Abstract
This work provides an insight into ongoing research aimed at designing a morphing wing with the ability to continuously adapt its aerodynamic shape. The wing is targeted at a general purpose unmanned aerial vehicle. The morphing wing concept outlined in here is based on continuous camber changes of the wing leading and trailing edges, allowing optimal performance in different flight regimes. The aeroelastic tailoring method is used to design the load carrying structure of the wing in order to define the optimal stiffness and strength of the structure, which are considered as fixed in subsequent design steps. The research proposes a novel modular design approach that combines aerodynamic shape optimisation and aeroelastic considerations for designing morphing wing surfaces.
Full text
Design of morphing wing for aerodynamic performance considering the wing flexibility effects Jan Navrátil, Vladimír Hostinský Institute of Aerospace Engineering , Faculty of Mechanical Engineering, Brno University of Technology, Czech Republic Jurij Sodja Faculty of Aerospace Engineering, Delft University of Technology, Netherlands 6th September 2023
Content 2 •Introduction of project BAANG •Context of presented research •Aero-structural optimization of morphing wing •Goals •Progress of the work EASN 2023, Salerno Italy, 5th - 8th September 2023
Project introduction and context of presented research 3EASN 2023, Salerno Italy, 5th - 8th September 2023
4 •responds to the call “Twinning” of Horizon Europe Framework Programme •connects 4 disciplines •aeronautics •mechatronics •mechanics of materials •additive manufacturing •connects 4 universities •Brno University of Technology •Delft University of Technology •Imperial College London •Vienna University of Technology Project BAANG introduction EASN 2023, Salerno Italy, 5th - 8th September 2023
5 Research goals within project BAANG •Design and manufacture of morphing wing •Establish an integrated design loop for morphing wing design EASN 2023, Salerno Italy, 5th - 8th September 2023
6 •Adaptation to particular flight conditions •Improvement of aerodynamic performance •Morphing of wing sections camber •Continuous along the span Idea of morphing wing EASN 2023, Salerno Italy, 5th - 8th September 2023
Max. take -off weight m 50 kg Wing planform area S w 2 .28 m 2 Wing span b 3 .8 m Wing root chord c r 0 .6 m Wing tip chord c t 0 .6 m Airfoil NACA 2510 Vs AD C -2 -1 0 1 2 3 4 5 010 20 30 40 50 60 Load factor, n Airspeed, V (m/s) Manuver envelope Flight envelope Gust line Flight envelope of the UAV Flight regime Flight speed Required lift coefficient of the aircraft Reynolds number at MAC V, m/s cLReMAC take -off 22.14 0.716 948755 cruise 40.0 0.219 1714125 loiter 24 0.609 1028475 landing 17.5 1.146 749930 •Target aircraft –UAV •Flight conditions •Flight envelope according to CS-VLA 7 Tab. 1 UAV basic geometric parameters Tab. 2 Design flight conditions Design conditions EASN 2023, Salerno Italy, 5th - 8th September 2023
Aero-structural optimization of morphing wing: Design of wingbox structure 8EASN 2023, Salerno Italy, 5th - 8th September 2023
Overview and tools •Goal: Set realistic wing stiffness for other design disciplines •Aeroelastic tailoring •Design in Proteus software (from TU Delft) •Vortex lattice method coupled to nonlinear Timoshenko beam model •Gradient based optimizer •Design parameters: •Lamination parameters •Design objective: •Minimum mass of the structure •Constraints: •Stress •Aeroelastic effects •Buckling •Baseline for further research: •Study possibilities of honeycomb structure in aeroelastic tailoring 9EASN 2023, Salerno Italy, 5th - 8th September 2023
CFD Solver settings 16 •Flow equations: Compressible RANS •Turbulence model: Spallart-Almaras •Convergence criteria: rms density < 1e-10 EASN 2023, Salerno Italy, 5th - 8th September 2023
CFD mesh 17 •Hybrid tetrahedral mesh with prismatic layers Volume elements ~ 5.8 millions Surface elements 156 000 Prismatic layers 18 EASN 2023, Salerno Italy, 5th - 8th September 2023
CFD mesh dependency study 18 •Loiter flight condition, fixed CL= 0.609 0.033 0.0335 0.034 0.0345 0.035 0.0355 0.036 0.0E+00 2.0E+06 4.0E+06 6.0E+06 8.0E+06 1.0E+07 1.2E+07 1.4E+07 Drag coefficient, CD Number of volume elements 5.64 5.66 5.68 5.70 5.72 5.74 5.76 5.78 0.0E+00 2.0E+06 4.0E+06 6.0E+06 8.0E+06 1.0E+07 1.2E+07 1.4E+07 Angle of attack Number of volume elements No. elements CLCD Rel. change: CD AoA Rel. change: AoA 3.47E+06 0.609 0.03569 - 5.77 - 5.80E+06 0.609 0.03340 - 6.4% 5.65 - 2.1% 7.42E+06 0.609 0.03387 1.4% 5.66 0.1% 1.23E+07 0.609 0.03429 1.3% 5.68 0.4% EASN 2023, Salerno Italy, 5th - 8th September 2023
Optimization problem 19 •Case 1 •Case 2 min CD subject to: CL= CL0 t = t0 Parameters: FFD, AoA min CD subject to: CL= CL0 Parameters: FFD, AoA EASN 2023, Salerno Italy, 5th - 8th September 2023
Optimization results, case 1 20 •Case 1 No. elements CLCDAoA Initial 0.609 0.03547 5.95 Optimal 0.609 0.03465 5.51 Rel. change - - 2.32% - 7.4% EASN 2023, Salerno Italy, 5th - 8th September 2023
Optimization results 21 •Case 2 No. elements CLCDAoA Initial 0.609 0.033405 5.65 Optimal 0.609 0.033375 5.95 Rel. change - - 0.09% - EASN 2023, Salerno Italy, 5th - 8th September 2023
Conclusion 22 •We have working aerodynamic shape optimization framework •There is challenge in connection of AESOPT with FSI iteration •Ongoing work - we should think about: •definition of optimization objective and constraints for particular flight cases •influence of wing planform on design space •constant chord over wing span restrict possibility to obtain elliptic distribution of CLc EASN 2023, Salerno Italy, 5th - 8th September 2023
Thank you for your attention! The authors would like to acknowledge the funding provided by the Horizon Europe programme of the European Union under Grant Agreement No. 101079091.