Gerard Schepers,

EU project AVATAR

AdVanced Aerodynamic Tools for lArge Rotors

2

13-2-2014

Project initiated by EERA *)

1. Energy Research Centre of the Netherlands, ECN (Coordinator)

2. Delft University of Technology, TUDelft

3. Technical University of Denmark, DTU

4. Fraunhofer IWES

5. University of Oldenburg, Forwind

6. University of Stuttgart, USTUTT

7. National Renewable Energy Centre, CENER

8. University of Liverpool, ULIV

9. Centre for Renewable Energy Sources and Saving, CRES

10. National Technical University of Greece, NTUA

11. Politecnico di Milano, Polimi

12. GE Global Research, Zweigniederlassung der General Electric Deutschland

Holding GmbH, GE

13. LM Wind Power, LM

*) European Energy Research Alliance

3

13-2-2014

Main motivation

UPSCALING towards 10-20 MW turbines

–Integrated design philosophy needed to make

these turbines technically feasible where

energy production is maximized in

conjunction with a minimization of loads

–Leads to:

• Lower induction Long slender blades

• Thick airfoils

• High tip speeds

• Passive (e.g. vg’s or spoilers) and active

(e.g. flaps) devices

4

13-2-2014

Motivation, ctd

Such 10MW+ rotors violate assumptions in current

tools, e.g.:

o Reynolds number effects,

o Compressibility effects

o Flow transition and separation,

o More flexible blades

10MW+ designs fall outside the validated range of current

state of the art tools.

5

13-2-2014

Avatar: Main objective

To bring the aerodynamic and fluid-structure models

to a next level and calibrate them for all relevant

aspects of large (10MW+) wind turbines

6

13-2-2014

Avatar: Work procedure

• Mobilize the entire chain of aerodynamic modeling ranging from

computational efficient ‘engineering’ tools to high fidelity, but

computationally expensive tools

• High fidelity tools feed information towards the lower complexity tools

• Validate tools against an experimental basis,

• Recent experiments from partners (DTU, Forwind, NTUA, TUDelft) ,

• New wind tunnel measurements:

• Pressurized DNW HDG wind tunnel

• Airfoil measurements at high Reynolds number and low Mach

• Airfoil measurements in LM wind tunnel

• Demonstrate the valueof the resulting tools on a large-scale rotor with

and without flow control devices

• INNWIND.EU reference rotor

• AVATAR reference rotor).

Work Packages/Work Package dependancy

7

13-2-2014

• WP1: Integration and evaluation

of 10 MW RWT

(CRES)

• WP2: Advanced aerodynamic

modelling

(DTU)

• WP3: Modelling of flow devices

and flow control

(CENER)

• WP4: Aeroelastic analysis of

large flexible blades

(NTUA)

NOTE: 48 months period

8

13-2-2014

WP2: Advanced aerodynamic modelling

The development of advanced aerodynamic tools for predicting

the aerodynamic performance of very large (D ~ 200 meter)

blades To assess and include Reynolds (~10 million) and Mach number effects

(Mach ~0.2-0.4) which occur at high tip speeds (~100-105 m/s) and at large

slender blades with thick (>35%) airfoils

Based on:

• Code to code comparison,

• Comparison with wind tunnel data

• Full scale data

9

13-2-2014

WP3: Aerodynamic models for flow devices

To predict the aerodynamic implications of flow devices at

sectional and blade level

To develop and validate low/intermediate models for large

blades with flow devices,

based on

–Experiments

–CFD

WP4: Aeroelastic analysis of large flexible blades

The assessment of the aeroelastic response of very

large blades To assess the effects of improved aerodynamic modeling from WP’s

2 and 3 on the aero-elastic behavior of large turbines with and without

flow devices

To assess CFD/aeroelastic couplings for specific load cases with

respect to large flexible rotor blades

To analyse effects of solidity, blade thickness, rotational speed and

structural tailoring

further upscaling to 20 MW turbines

10

13-2-2014

WP1: Integration and evaluation of 10 MW RWT

Design of a reference rotor adjacent to the Innwind.EU

reference rotor

Demonstrate improvements in modeling and assess validity

of improvements for 10MW+ rotors

Assessment of models using pre-set evaluation criteria:

– Amount of empirism in the models,

– Calculational time

– Differences between models

– Robustness

– Time to set-up calculation

To lay the basis for a large scale aerodynamic experiment

11

13-2-2014

12

13-2-2014

EERA Field experiment, background

Wind tunnel measurements and field measurements should be seen

as COMPLEMENTARY

– Wind tunnel measurements are done at well known (but less

representative) conditions

– Field measurements are done at representative (but less known)

conditions

We see initiatives on wind tunnel measurements (e.g. New

Mexico/NASA-Ames/TUDelft) but not on field measurements:

The time is ripe for a PUBLIC aerodynamic field experiment on a

wind turbine representative for the current and future generation

of wind turbines based on:

– Most innovative measurement techniques

– Initiated under auspices of EERA (European Energy Research

Alliance)AVATAR

WP1: AVATAR and INNWIND.EU RWT

• Both turbines are 10MW

• AVATAR rotor placed on INNWIND.EU Reference

turbine.

• AVATAR rotor has lower induction, larger rotor

diameter and higher tip speed and therefore

serves as a more challenging test case

13

13-2-2014

Where are we now?

• Project was submitted on November 28th 2012

• Project was approved in March 2013 under the

condition that a 20% budget reduction could be

implemented

• Thereafter we went through a long negotiation

process in which many modifications were made.

• The EU promised us that we start on November

1st 2013 and asked us to arrange the kick-off

meeting in November *)

*) either 14/15 or 25/26 or 26/27 november

14

13-2-2014