Wind Field Reconstruction in the Induction Zone Olivia Brissette - PowerPoint PPT Presentation

Wind Field Reconstruction in the Induction Zone Olivia Brissette (Engie) A Round Robin Exercise Daniel Cabezón (EDPR) Marijn F. van Dooren (ForWind) Richard Foreman (UL) Julia Gottschall (Fraunhofer IWES) Paul Housley (SSE) Alkistis Papetta (Fraunhofer IWES) Anantha P. K. Sekar (ForWind) Eric Simley (NREL) Chris Slinger (ZX Lidars) Nicolai Gayle Nygaard WESC 2019

Motivation U 2.5D /U ∞ = ? • Power curve measurements • Interpretation of sales power curves • AEP calculations 2

Round robin data Data filtered for Freestream wind directions – Turbine operating normally – Data shared Lidar radial wind speeds at 10 ranges – Lidar tilt and roll angles – Experiment geometry – www.aventlidartechnology.com 3

Round robin format 1 + Induction U ∞ , a = model Lidar LOS wind speeds Participant choice Result 3 2 Dialogue to eliminate misunderstandings Report back using Excel template 4

Round robin contributions 8 4 1 1 1D centreline Troldborg & CFD Vortex sheet Forsting 5

Induction models 1D centreline Medici et al (2011) – Applies on induction zone – centreline 1. Reconstruct centreline wind speed from LOS 2. Fit to induction model 6

Induction models 3 participants Neglect 0.11D lidar position offset 5 participants Include lidar position offset 7

Induction models 8

Induction models Troldborg & Forsting 1D centreline Troldborg & Forsting (2017) Medici et al (2011) – – Combines 1D model with Applies on induction zone – – radial induction profile centreline Fit LOS directly 1. Reconstruct centreline – wind speed from LOS 2. Fit to induction model 9

Wind speed reduction Fitting only outer lidar ranges Generic thrust curve used to find induction factor 10

Induction models Troldborg & Forsting 1D centreline Troldborg & Forsting (2017) Medici et al (2011) – – Combines 1D model with Applies on induction zone – – radial induction profile centreline Fit LOS directly 1. Reconstruct centreline – wind speed from LOS 2. Fit to induction model CFD RANS with actuator disk – Guessed turbine thrust curve – 1. Reconstruct centreline wind speed from LOS 2. Compare with CFD results 3. Extrapolate to 10D upstream distance 11

Wind speed reduction 12

Induction models Troldborg & Forsting 1D centreline Troldborg & Forsting (2017) Medici et al (2011) – – Combines 1D model with Applies on induction zone – – radial induction profile centreline Fit LOS directly 1. Reconstruct centreline – wind speed from LOS 2. Fit to induction model CFD Vortex sheet RANS with actuator disk Branlard (2015) – – Guessed turbine thrust curve Full 2D analytical model – – 1. Reconstruct centreline wind speed from LOS Resolves axial and – transverse motion 2. Compare with CFD results Includes ground effect – 3. Extrapolate to X=-10D 13

Wind speed reduction 14

Induction factor 𝑉 𝑦 = 0 = 1 − 𝑏 𝑉 ∞ Betz limit 15

U 1 U 2 Centreline, Medici et al. formula U 1 > U 2

Conclusions Approximately 1% reduction of wind speed 2.5D upstream Splitting wind field Integrating wind field Larger induction effect reconstruction and reconstruction and induction model induction model Including induction Larger induction effect Including only induction effect on both axial effect on axial motion and transverse motion Larger induction effect Including ground effect Isolated rotor and other turbines 17

Round Robin – version 2 Objective Model induction from entire array – Find influence on the nacelle lidar measurements – Dataset Same as Round Robin v1 – Wind farm details added – Timeline Starts today – NICNY@orsted.dk Deadline for submission: 1 November 2019 – 18