evan gaertner university of massachusetts, amherst igert seminar series october 1st, 2015 floating...
DESCRIPTION
3 Floating Offshore Wind Turbines Advantages: Access to deeper water More useable area Further from onshore lines of site Reduce impact to important near shore habitats Simplified installation Tow-out installation Reduce environmental impacts from pile drivingTRANSCRIPT
![Page 1: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/1.jpg)
Evan GaertnerUniversity of Massachusetts, Amherst
IGERT Seminar SeriesOctober 1st, 2015
Floating Offshore Wind Turbine Aerodynamics and Optimization
Opportunities
![Page 2: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/2.jpg)
2
Agenda
Floating Wind Turbine Aerodynamics Dynamics Stall Design Optimization
![Page 3: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/3.jpg)
3
Floating Offshore Wind TurbinesAdvantages:Access to deeper water
• More useable area• Further from onshore lines of site• Reduce impact to important near shore
habitatsSimplified installation
• Tow-out installation• Reduce environmental impacts from pile
driving
![Page 4: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/4.jpg)
4
Platform Motion
Wind and wave loading Non-rigid mooring system
Complex platform motion • 6 transitional and rotational Degrees of Freedom
Adverse Affects:• Increased aerodynamic complexity• Stronger cyclical loading• Requires more sophisticated controls
![Page 5: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/5.jpg)
5
Velocity from Platform MotionSkewed flowFrom pitch or yawBlade moves
• Toward wind: increased velocity• Away from wind: decreased velocity
Occurs at rotational frequency
Wake interactionFrom pitch or surgeRotor moves through its own wakeCan causes flow reversals and turbulenceOccurs at platform motion frequency
![Page 6: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/6.jpg)
6
Wake Induced Dynamic Simulator (WInDS)
A free-vortex wake method• Developed to model rotor-scale
unsteady aerodynamics By superposition, local velocities
are calculated from different modes of forcing
Previously neglected blade section level, unsteady viscous effects
induced platformU U U U [2]
![Page 7: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/7.jpg)
Blade Scale Unsteadiness
![Page 8: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/8.jpg)
8
Quasi-Steady Aerodynamics Aerodynamic properties of
airfoils determined experimentally in wind tunnels
Lift increases linearly with angle of attack (α)
At a critical angle, flow separates and lift drops• “Stall”
WInDS used quasi-steady data
![Page 9: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/9.jpg)
9
Dynamic Stall
![Page 10: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/10.jpg)
10
Dynamic Stall Flow MorphologyStage 1 Stage 2 Stage 2-3 Stage 3-4 Stage 5
[3]
Lift C
oef,
C L
Drag
Coe
f, C D
Mom
ent C
oef,
C M
Angle of Attack, α (°) Angle of Attack, α (°) Angle of Attack, α (°)
![Page 11: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/11.jpg)
11
Modeling Dynamic Stall: Leishman-Beddoes (LB) Model Semi-empirical method
• Use simplified physical representations• Augmented with empirical data
Model Benefits• Commonly used, well documented• Minimal experimental coefficients• Computationally efficient
[3]
![Page 12: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/12.jpg)
12
Example 2D LB validation: S809 Airfoil, k = 0.077, Re = 1.0×106
10 15 20 25 30
0.5
1
1.5
2
Coe
f. of
Lift
, Cl
Angle of Attack, [ ]
mean=20 , amplitude=10
10 15 20 25 30
0.5
1
1.5
2
Coe
f. of
Lift
, Cl
Angle of Attack, [ ]
mean=20 , amplitude=10
5 10 15 20 25
0.5
1
1.5
2
Coe
f. of
Lift
, Cl
Angle of Attack, [ ]
mean=14 , amplitude=10
5 10 15 20 25
0.5
1
1.5
2
Coe
f. of
Lift
, Cl
Angle of Attack, [ ]
mean=14 , amplitude=10
0 5 10 15 20
0
0.5
1
1.5
Coe
f. of
Lift
, Cl
Angle of Attack, [ ]
mean=8 , amplitude=10
0 5 10 15 20
0
0.5
1
1.5
Coe
f. of
Lift
, Cl
Angle of Attack, [ ]
mean=8 , amplitude=10
LB model validated against 2D pitch oscillation data
10 15 20 25 30
0.5
1
1.5
2
Coe
f. of
Lift
, Cl
Angle of Attack, [ ]
mean=20 , amplitude=10
10 15 20 25 30
0.5
1
1.5
2
Coe
f. of
Lift
, Cl
Angle of Attack, [ ]
mean=20 , amplitude=10
5 10 15 20 25
0.5
1
1.5
2
Coe
f. of
Lift
, Cl
Angle of Attack, [ ]
mean=14 , amplitude=10
5 10 15 20 25
0.5
1
1.5
2
Coe
f. of
Lift
, Cl
Angle of Attack, [ ]
mean=14 , amplitude=10
0 5 10 15 20
0
0.5
1
1.5
Coe
f. of
Lift
, Cl
Angle of Attack, [ ]
mean=8 , amplitude=10
0 5 10 15 20
0
0.5
1
1.5
Coe
f. of
Lift
, Cl
Angle of Attack, [ ]
mean=8 , amplitude=10
![Page 13: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/13.jpg)
13
WInDS-FAST Integration WInDS was originally written as a standalone
model in Matlab• Decouples structural motion and the aerodynamics
Integrated into FAST v8 by modifying the aerodynamic model, AeroDyn • Fully captures the effects of aerodynamics and
hydrodynamics on platform motions changes the resulting aerodynamics
OC3/Hywind Spar Buoy
![Page 14: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/14.jpg)
Design Optimization
![Page 15: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/15.jpg)
15
Rotor DesignDesign ProcessStart with known optimal blade shapeModify for practical structural and manufacturing concerns
ProblemUses ideal conditions for aerodynamic analysis: uniform, steady, non-skewed flow
Typical optimization projects in the literation:More sophisticated modelsMore design variables
![Page 16: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/16.jpg)
16
Research Goal Inform design process with realistic
probability distributions of steady and unsteady condition• Operating conditions are never ideal!
Include minimization of load variability as a design goal
![Page 17: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/17.jpg)
17
Integrated Design of Offshore Wind Turbines
Process: Sequential design of subsystems
Problem:Optimized subsystemsSub-optimal global system
Solution:Multi-objective, multi-disciplinary, iterative optimization
TurbineDesign
Platform Design Controls
![Page 18: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/18.jpg)
18
Interdisciplinary OpportunitiesAdditional design goals could include:Lower tip speed ratios
• Reduce risk of bird strikesLarger turbine rotors
• Allow smaller wind farms with fewer seafloor disturbancesOptimization for deeper waters farther from shore
• Reduce competition for use or view-shed concerns
Open to suggestions for other interdisciplinary objects!
![Page 19: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/19.jpg)
Questions?
Evan [email protected]
This work was supported in part by the NSF-sponsored IGERT: Offshore Wind Energy Engineering, Environmental Science, and Policy
and by the Edwin V. Sisson Doctoral Fellowship
Thank You!
![Page 20: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/20.jpg)
Supplemental Slides
![Page 21: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/21.jpg)
21
Span-wise Unsteadiness
0.2 0.4 0.6 0.8 10
0.05
0.1
0.15
Blade Span, r/R
Ave
rage
Red
uced
Fre
quen
cy, k
Spanwise kQuasi-steady line
AoA predominately varying cyclically with rotor rotation, driven by:• Mean platform pitch: ~4-5°• Rotor shaft tilt: 5°
0.2 0.4 0.6 0.8 10.05
0.1
0.15
Blade Span, r/R
CL S
tand
ard
Dev
iatio
n
LB ModelStatic Data
![Page 22: Evan Gaertner University of Massachusetts, Amherst IGERT Seminar Series October 1st, 2015 Floating Offshore Wind Turbine Aerodynamics](https://reader035.vdocuments.us/reader035/viewer/2022062600/5a4d1b4d7f8b9ab0599a5fd9/html5/thumbnails/22.jpg)
22
Dynamic Stall
10 12 14 16 18
1.3
1.4
1.5
1.6
1.7
1.8
Angle of Attack, ( )
Lift
Coe
f., C
L
Span Location r/R = 0.186
LB ModelStatic Data
5 6 7 80.9
1
1.1
1.2
1.3
1.4
Angle of Attack, ( )
Lift
Coe
f., C
L
Span Location r/R = 0.381
LB ModelStatic Data