3D Dynamic Stall Modelling

on the NREL phase VI

Parked Blade

ALVARO GONZALEZ

XABIER MUNDUATE

47th AIAA Aerospace Sciences Meeting and Exhibit

Orlando, Florida, 5 – 8 Jan 2009

Contents

Background and Motivation How DS differs 2D-3D:

Experimental analysis dynamic stall 2D S809 aerofoil sinusoidal pitching Parked Blade under the same motions

Why DS differs 2D-3D:Dynamic stall modelling Parked blade

Conclusions

Background and Motivation

Understanding of the 3D unsteady aerodynamics. Particularly dynamic stall on a Parked Blade.

Reduce uncertainty on loads prediction. Current deviations up to 30% on loads calculations.

Traditionally “loads envelop” implies Parked blade unsteady aerodynamics loads to be a design driver that constrain the blade platform tailoring.

Wind turbine blade unsteady load calculations still relay on 2D sectional steady data.

How and Why 3D Dynamic Stall

2D S809 AEROFOIL sinusoidal oscillatory pitching from OSU.

PARKED BLADE NREL PHASE VISequence O, the same sinusoidal oscillatory pitching than OSU.

BASED ON 2D S809 STEADY DATAfrom OSU.

BASED ON SECTIONAL PARKED BLADE STEADY DATA NREL PHASE VISequence L.

3D DYNAMIC STALL STUDY3D DYNAMIC STALL STUDY

NREL phase VI parked blade experimental data

NREL phase VI Parked blade Sequence O.

Sinusoidal motions of the blade at 12 o’clock position.

Oscillations AOA=8±10 deg and AOA=20 ±10 deg

30% 47% and 80% blade span sections

Low and high reduced frequency pitching motions:

k= 0.025 and k= 0.075.

How DS differs 2D-3D:Experimental analysis dynamic stall

Parked blade 30% section.

AOA=8±10deg.

k=0.025

Parked blade 30% section.

AOA=8±10deg.

k=0.025

How DS differs 2D-3D:Experimental analysis dynamic stall

Parked blade 47% section.

AOA=8±10deg.

k=0.025

Parked blade 47% section.

AOA=8±10deg.

k=0.025

How DS differs 2D-3D:Experimental analysis dynamic stall

Parked blade 80% section.

AOA=8±10deg.

k=0.025

Parked blade 80% section.

AOA=8±10deg.

k=0.025

Why DS differs 2D-3D: Dynamic stall modelling

Cm Prediction Parked blade 30% section.AOA=8±10deg.

k=0.025

Cm Prediction Parked blade 30% section.AOA=8±10deg.

k=0.025

Cn Prediction Parked blade 30% section.AOA=8±10deg.

k=0.025

Cn Prediction Parked blade 30% section.AOA=8±10deg.

k=0.025

Why DS differs 2D-3D: Dynamic stall modelling

Cm Prediction Parked blade 47% section.AOA=20±10deg.

k=0.025

Cm Prediction Parked blade 47% section.AOA=20±10deg.

k=0.025

Cn Prediction Parked blade 47% section.AOA=20±10deg.

k=0.025

Cn Prediction Parked blade 47% section.AOA=20±10deg.

k=0.025

Why DS differs 2D-3D: Dynamic stall modelling

Cm Prediction Parked blade 80% section.AOA=20±10deg.

k=0.025

Cm Prediction Parked blade 80% section.AOA=20±10deg.

k=0.025

Cn Prediction Parked blade 80% section.AOA=20±10deg.

k=0.025

Cn Prediction Parked blade 80% section.AOA=20±10deg.

k=0.025

Conclusions

THANK YOU FOR YOUR ATTENTION

THANK YOU FOR YOUR ATTENTION