3. Aerodynamic Objective
• Design wind turbine blades to be manufactured and flown
for research on wakes in an array
• Create same initial conditions velocity/momentum deficit at
rotor plane as fullscale machine
• What shape does the blade need to produce scaled wake?
2
5. How Is a Wake Created?
Γ
r
R
=
Γ( r
R )
RU∞
=
Cl
2
W
U∞
c
R
• Circulation is
proportional to lift
• Lift forces determine
shed circulation
4
6. Objective Function, Γfs
• most common wind turbine in USA, GE 1.5sle, GE37c
• full-scale turbine model provided by manufacturer
• modeled in WT_Perf
• λ = 9
• smooth surface airfoil data from wind tunnel
5
7. Objective Function, Cl
• for a given circulation, Cl determines local solidity
• adequate stall margin
• efficient L/D
• smooth chord and twist distribution
• Cl = 0.6
Γ
r
R
=
Cl
2
W
U∞
c
R
6
8. Airfoil Selection Criteria
• Rec ≈ 2,000,000
• high quality, public, and low turbulence wind tunnel data
• fixed transition, roughness, and unsteady data
• roughness insensitivity
• thickness requirements
7
9. Airfoil Selection
S814 (t
c = 0.24) and S825 (t
c = 0.17)
Cd
0 0.01 0.02 0.03
Cl
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
S825 Re 1E6
S825 Re 2E6
S825 Re 3E6
S825 Re 4E6
S825 Re 6E6
S814 Re 0.7E6
S814 Re 1E6
S814 Re 1.5E6
S814 Re 2E6
S814 Re 3E6
, [deg]
-5 0 5 10 15 20
8
10. Inverse Design
• created inverse
design tool
• solved for chord and
twist
• iterate with WT_Perf
RMSE Γ
0.08 0.085 0.09 0.095 0.1
RMSEα
0
0.2
0.4
0.6
0.8
9
22. Conclusions
• inverse design tool implemented to design blades to
produce a specific wake
• blade geometry creates scaled wake of commercial 1.5 MW
turbine
• 3D CFD indicates no issues in using 2D for blade root for
this design
• NRT blade to be flown at SWiFT and used for wake
experiments
21