Wakes and wake interaction between rotors and discs in an experimental model array

V L Okulov,R F Mikkelsen,J N Sørensen,I V Litvinov,I K Kabardin,I V Naumov

doi:10.1088/1742-6596/1256/1/012013

V L Okulov, R F Mikkelsen + Show 4 more

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https://doi.org/10.1088/1742-6596/1256/1/012013

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Abstract

The aim of the present paper is to obtain a better understanding of wakes generated by 2, 3 and 4 elements (disks and/or rotors) modeling an array of wind turbines in a wind farm. We here extend the results from our previous experimental model studies on the correlation between the behavior of the wake behind dual configurations of passive disks and active rotors to establish new knowledge regarding the wake development behind the 3rd and 4th rotor operating in a wake. To accomplish this, 2D PIV velocity measurements were carried out to investigate the flow properties upstream and downstream the tested rotors and discs in the array. The study also provides measured values of power and thrust coefficients of the model turbines using strain gauges installed directly on the rotors. The aim of the laboratory experiment is to provide data to calibrate and validate wake models for design and analysis arrays of wind turbines located in wind farms.

Highlights

In wind farms, the optimization of operating conditions requires more studies when several wind turbines are located after each other in an array [1,2,3,4]
The aim of the present paper is to obtain a better understanding of wakes generated by 2, 3 and 4 elements modeling an array of wind turbines in a wind farm
The effect of power stabilization needs to be studied and further explained. This vortex wakes and vortex structures behind different single and dual configurations of disks and/or rotors modeling the wind turbines were the subject of our previous laboratory tests [7,8,9,10,11,12]

Summary

Introduction

The optimization of operating conditions requires more studies when several wind turbines are located after each other in an array [1,2,3,4]. The effect of power stabilization needs to be studied and further explained This vortex wakes and vortex structures behind different single and dual configurations of disks and/or rotors modeling the wind turbines were the subject of our previous laboratory tests [7,8,9,10,11,12]. Our experiments [8,9,10,11] indicated that any single or dual disk system cannot satisfactorily replace the same system with rotors when analyzing wake properties behind them It was found, as an overall conclusion in [12], that discs can be used to replace rotors when carrying out laboratory tests of wind-farm models, but they should not be located just upstream of the rotor being investigated. Using this as a general rule permits us in the current investigation to expand the setup to comprise arrays of 2, 3 and 4 rotors in our laboratory model of rotor arrays

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