The document presents a study on the aerodynamic performance of a morphing wing for race cars inspired by bird wing properties, focusing on the effects of passive camber on performance across different Reynolds numbers. It describes methods of numerical and experimental simulations, comparisons, and validations to establish an idealized morphing wing design. Key findings reveal how camber and Reynolds number influence aerofoil efficiency, highlighting the removal of laminar separation as crucial to improving performance.

1. Aerodynamic Performance of a Morphing Wing
MSc Race car Aerodynamics
Cyril Jacques (28190343) – supervised by Dr. R. de Kat & Dr. J. W. Kim
Introduction
• The inspiration of this project comes from bird’s smart properties to improve
aerodynamic performance of wings
• Different types of morphing are possible: active, passive; camber, spanwise, etc.
Aim
Understand how a passive camber morphing wing affects
aerodynamic performance
Objectives
• Numerically and experimentally determine the
aerodynamic performance of differently cambered wings
for a Reynolds number range between 10,000 and
1,000,000
• Create an idealised passive morphing wing
• Explore methods of creating and testing a passive
morphing wing
Comparison & Validation
• Aerofoil E387 tested to validate previous results
• 3 Reynolds number tested included within our Reynolds number range
Methodology
• Define morphing parameter(s)
• Choose suitable aerofoil profile for Reynolds number range
• 2D simulations on XFoil changing the camber from 0% up to 6%
• Further CFD simulations including 2D, 2.5D and 3D using Star CCM+
• Test the aerofoil profiles in the wind tunnel using a force balance
• Compare CFD and experimental results
• Set the final settings for a passive morphing wing
• Find a material able to be recreate a suitable camber morphing
• Test it in a wind tunnel, compare with previous tests
Poster number: 70
Time: 9:30-12:30
0
50
100
150
200
250
0 2 4 6 8
Efficiency
Angle of attack α
Reynolds number’s effect on the efficiency, 5.4%
camber
Re=10,000
Re=20,000
Re=40,000
Re=80,000
Re=200,000
Re=500,000
Re=1,000,000
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0 0.02 0.04 0.06 0.08
Cl
Cd
Cl against Cd, Re= 40,000, Free transition
0% camber
1% camber
2% camber
4% camber
5.4% camber
6% camber
0
5
10
15
20
25
30
35
40
45
0 1 2 3 4 5 6 7 8
Efficiency
Angle of attack α
Influence of camber on the efficiency, Re=40,000
0% camber
1% camber
2% camber
4% camber
5.4% camber
6% camber
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0 0.02 0.04 0.06 0.08
Cl
Cd
Cl against Cd, Re= 40,000, Transition fixed at x=0.4
0% camber
1% camber
2% camber
4% camber
5.4% camber
6% camber
Results
• Reynolds number and camber affect aerofoil performance
• For low Reynolds number, laminar separation bubble decreases the
performance
• Fixing transition can remove the laminar separation bubble
• With a fixed transition at x=0.4, Cl/Cd polar is well behaved
Outcomes & Further work
• Laminar separation can be removed by forcing transition
• Structured mesh using Gambit is accurate and can be further used
• γ Re θ transition model will be used for 2.5D and 3D sims
• 2.5D sims on Star CCM+ using the Gambit structured mesh
• 3D sims using an unstructured mesh on Star CCM+
• Design & build aerofoil models and mounts (Solidworks & 3D printing)
• Perform experiments and compare with numerical results
• Use results to define idealised passive morphing wing
• Time permitting realise a true morphing wing
• Explore implications of this concept for race cars application
Eppler 63, 5.4% camber
References: [1] D. Lentink, U.K. Muller, E.J. Stamhuis, R. de Kat, W. van Gestel, L.L.M. Veldhuis, P.Henningsson, A. Hedenstrom, .J.J. Videler, and J.L. van Leeuwen, "How Swifts Control their Glide Performance with Morphing Wings", Nature, 26 April 2007
[2] http://www.formula1-dictionary.net/flexi front wings rbr.html, accessed the 5 March 2016
[3] J. S. Hill, “Mammoth 50 MW Wind Turbine Blades could revolutionize offshore wind in US”, Illustration courtesy of TrevorJohnston.com/Popular Science, accessed the 11 July 2016
[4] Experimental results: T. J. Mueller, “Proceedings of the conference on low Reynolds number airfoil aerodynamics”, version edited in June 1985 UNDAS-CP-77B123, R. Eppler & D. M. Somers “Airfoil Design for Reynolds numbers between 50,000 and 500,000”
• Structured mesh created on Gambit using the E63 aerofoil
• Tested different turbulence models on Star CCM+
• K omega SST with γRe θ transition model has proven to be the best
Eppler 63, 2% camber
Thickness Camber
Maximum 0.0427 0.02
Position 0.218 0.516
Thickness Camber
Maximum 0.0427 0.054
Position 0.218 0.515
Fig. 13: E63 5.4% camber aerofoil tested at 7 degrees running the K-ω SST
turbulence model with γ Re θ transition model
Fig. 1: Natural morphing wing [1] Fig.2: Passive span wise bending of a front wing [2] Fig. 3: Active wind turbine [3]
Fig. 4: Aerofoil profile and its section characteristics
Fig. 5: Reynolds number comparison in terms of efficiency, E63 5.4% camber Fig. 6: Maximum camber comparison in terms of efficiency, Re=40,000 Fig. 7: Characterisation of the laminar bubble separation, Re=40,000 Fig. 8: Well behaved polar after fixing transition at x=0.4 , Re=40,000
Fig. 9: Validation of the XFoil model at Re=60,000
Fig. 10: Validation of the XFoil model at Re=200,000
• XFoil has shown to be accurate, allows
us to be confident in our results
• With the Reynolds number
increasing, XFoil accuracy is
increasing
10
15
20
25
30
35
40
0 2 4 6 8
Efficiency
Cd
Mesh comparison
Coarse mesh: 93000 cells
Mesh refined on the
suction side:112500 cells
Mesh refined on both
sides:110250 cells
Fig. 14: Zoom in on the laminar bubble separation at the
leading edge
Fig. 12: Mesh convergence validationFig. 11: Turbulence models comparison
15
20
25
30
35
40
45
0 2 4 6 8
Efficiency
Cd
Efficiency against angle of attack, E63 5.4%, Re=40,000
XFoil
K omega SST with yRe
Theta transition
Spalart Allmaras
K omega SST
-0.3
-0.1
0.1
0.3
0.5
0.7
0.9
1.1
1.3
0 0.01 0.02 0.03 0.04 0.05
Cl
Cd
Cl against Cd, E387, Re=60,000
Xfoil
Experimental [4]
Prandtl Boundary layer
concept [4]
Experimental (camber
3.8%) [4]
-0.3
-0.1
0.1
0.3
0.5
0.7
0.9
1.1
1.3
0 0.01 0.02 0.03
Cl
Cd
Cl against Cd, E387, Re=200,000
Xfoil
Experimental [4]
Prandtl Boundary layer
concept [4]
Experimental (camber
3.8%) [4]