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]