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Influence of tower shadow on downwind flexible rotors: Field tests and simulations

Journal Article · · Wind Energy
DOI:https://doi.org/10.1002/we.2703· OSTI ID:1834240
 [1];  [1];  [1]
  1. Department of Mechanical and Aerospace Engineering University of Virginia Charlottesville Virginia USA
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Abstract

As wind turbine rotors become larger, the blades become more flexible, requiring extra stiffness and cost to avoid the risk of tower strike. Wind turbines in a downwind configuration have a reduced risk of tower strike because the rotor thrust acts away from the tower. However, downwind blades pass through the wake of the tower, and the resulting load variation may contribute to blade fatigue. To date, there have been no field tests to quantify this tower shadow effect on unsteady blade moments. The present study reports on the first field testing of a flexible, downwind, coned rotor and compares the experimental data against simulations run in OpenFAST. The tower shadow effect is simulated using the conventional Powles model and a new Eames model (developed herein), which includes the influence of upstream turbulence. Both models reasonably predict the blade root out‐of‐plane bending moment data and the tower shadow dip magnitude when compared to field test data in Region 3. Tower shadow was found to increase the short‐term Damage Equivalent Loads (DELs) by less than 10% compared to other effects (gravity, shear, and turbulence), and the predictions were consistent with experiments. These results indicate that the tower shadow effect can be reasonably modeled with the simpler Powles model and that the tower shadow effect can be small compared to the effect of turbulence. However, long‐term fatigue due to tower shadow should be included in detailed structural analysis and design of the rotor and the tower.

Sponsoring Organization:
USDOE
Grant/Contract Number:
NONE; AR0000667
OSTI ID:
1834240
Alternate ID(s):
OSTI ID: 1834242
Journal Information:
Wind Energy, Journal Name: Wind Energy Journal Issue: 5 Vol. 25; ISSN 1095-4244
Publisher:
Wiley Blackwell (John Wiley & Sons)Copyright Statement
Country of Publication:
United Kingdom
Language:
English

References (27)

Downwind pre-aligned rotors for extreme-scale wind turbines: Downwind pre-aligned rotors for extreme-scale wind turbines journal January 2017
Tower shadow induced blade loads for an extreme‐scale downwind turbine journal December 2019
Gravo‐aeroelastic scaling of a 13‐MW downwind rotor for 20% scale blades journal September 2020
Multi‐fidelity digital twin structural model for a sub‐scale downwind wind turbine rotor blade journal May 2021
The influence of turbulence on drag journal January 1979
A Comparative study on the aeromechanic performances of upwind and downwind horizontal-axis wind turbines journal May 2018
A calibration method for downwind wake models accounting for the unsteady behaviour of the wind turbine tower shadow behind monopile and truss towers journal October 2013
Measurements and predictions of wind turbine tower shadow and fairing effects journal August 2018
Pre-aligned downwind rotor for a 13.2 MW wind turbine journal February 2018
A gravo-aeroelastically scaled wind turbine rotor at field-prototype scale with strict structural requirements journal August 2020
Experiments on the flow past a circular cylinder at very high Reynolds number journal May 1961
Pressure distributions on circular cylinders at critical Reynolds numbers journal February 1973
The simultaneous effect of a fairing tower and increased blade flexibility on a downwind mounted rotor journal May 2013
Servo-aero-gravo-elastic (SAGE) scaling and its application to a 13-MW downwind turbine journal November 2020
The growth of a cylinder wake in turbulent flow journal January 2011
Load Equivalent Tower Shadow Modeling for Downwind Turbines journal January 2007
Unsteady Aerodynamics Experiment Phase VI: Wind Tunnel Test Configurations and Available Data Campaigns report December 2001
AeroDyn Theory Manual report January 2005
Aerodynamic Design of the 13.2 MW SUMR-13i Wind Turbine Rotor conference January 2018
Design and Testing of a Scaled Demonstrator Turbine at the National Wind Technology Center conference January 2019
Field Tests and Simulations of Tower Shadow Effect for a Downwind Turbine conference January 2021
Combined Blade-Element Momentum—Lifting Line Model for Variable Loads on Downwind Turbine Towers journal September 2018
Effect of Rotor Thrust on the Average Tower Drag of Downwind Turbines journal January 2019
Dynamic Stall Model for Tower Shadow Effects on Downwind Turbines and Its Scale Effects journal October 2020
System-level design studies for large rotors journal January 2019
Redesign of an upwind rotor for a downwind configuration: design changes and cost evaluation journal January 2021
Wind pressure on circular cylinders and chimneys journal July 1930

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