Near and far field flow disturbances induced by model hydrokinetic turbine: ADV and ADP comparison

Vincent S. Neary, Budi Gunawan, Craig Hill, Leonardo P. Chamorro

Research output: Contribution to journalArticle

Abstract

Wake flows downstream of hydrokinetic turbines are characterized by hub and tip vortices, a velocity deficit and an increase in turbulence intensity. Velocity and turbulence recovery in the wakes of individual turbines constrains the density of turbines in an array and limits the amount of energy that can be produced by a turbine farm. However, few hydrokinetic turbine flow recovery studies have been conducted, especially on the far-field flow characteristics. Nor have studies evaluated the accuracy of acoustic Doppler profiler measurements in the wakes of turbines. The present study examines vertical profiles of mean velocity and turbulence, as well as longitudinal profiles of velocity deficit and turbulence levels measured at the symmetry plane of a model three-blade axial flow turbine in a large open channel flow. Mean velocity and turbulence statistics are measured using an acoustic Doppler velocimeter (ADV) and a pulse coherent acoustic Doppler profiler (ADP). ADV and corrected-ADP derived values of mean velocity, turbulence intensity and root-mean-square velocity constitute a well-documented data set that can be used to validate numerical models simulating the effects of hydrokinetic turbine arrays. We found that 80% of the flow recovery occurred about ten diameters downstream from the rotor plane, which suggests that practical values for longitudinal spacing of turbines should be between ten and fifteen diameters. Significant errors observed in mean velocity and turbulence statistics derived from ADP measurements in the near wake region raise concerns on the use of these instruments for such measurements in lab and field studies. Although the cause of some of the errors requires further investigation, we show that errors in turbulence intensity can be successfully corrected with supplemental ADV measurements.

Original languageEnglish (US)
Pages (from-to)1-6
Number of pages6
JournalRenewable Energy
Volume60
DOIs
StatePublished - Dec 1 2013

Fingerprint

Velocimeters
Flow fields
Turbines
Acoustics
Turbulence
Recovery
Statistics
Open channel flow
Axial flow
Farms
Turbomachine blades
Numerical models
Vortex flow
Rotors

Keywords

  • Acoustic Doppler current profiler
  • Acoustic Doppler velocimeter
  • Hydrokinetic turbine
  • Marine renewable energy
  • Tidal energy
  • Wake recovery

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment

Cite this

Near and far field flow disturbances induced by model hydrokinetic turbine : ADV and ADP comparison. / Neary, Vincent S.; Gunawan, Budi; Hill, Craig; Chamorro, Leonardo P.

In: Renewable Energy, Vol. 60, 01.12.2013, p. 1-6.

Research output: Contribution to journalArticle

@article{ca2592be54cb4759a99ddeb20b68f211,
title = "Near and far field flow disturbances induced by model hydrokinetic turbine: ADV and ADP comparison",
abstract = "Wake flows downstream of hydrokinetic turbines are characterized by hub and tip vortices, a velocity deficit and an increase in turbulence intensity. Velocity and turbulence recovery in the wakes of individual turbines constrains the density of turbines in an array and limits the amount of energy that can be produced by a turbine farm. However, few hydrokinetic turbine flow recovery studies have been conducted, especially on the far-field flow characteristics. Nor have studies evaluated the accuracy of acoustic Doppler profiler measurements in the wakes of turbines. The present study examines vertical profiles of mean velocity and turbulence, as well as longitudinal profiles of velocity deficit and turbulence levels measured at the symmetry plane of a model three-blade axial flow turbine in a large open channel flow. Mean velocity and turbulence statistics are measured using an acoustic Doppler velocimeter (ADV) and a pulse coherent acoustic Doppler profiler (ADP). ADV and corrected-ADP derived values of mean velocity, turbulence intensity and root-mean-square velocity constitute a well-documented data set that can be used to validate numerical models simulating the effects of hydrokinetic turbine arrays. We found that 80{\%} of the flow recovery occurred about ten diameters downstream from the rotor plane, which suggests that practical values for longitudinal spacing of turbines should be between ten and fifteen diameters. Significant errors observed in mean velocity and turbulence statistics derived from ADP measurements in the near wake region raise concerns on the use of these instruments for such measurements in lab and field studies. Although the cause of some of the errors requires further investigation, we show that errors in turbulence intensity can be successfully corrected with supplemental ADV measurements.",
keywords = "Acoustic Doppler current profiler, Acoustic Doppler velocimeter, Hydrokinetic turbine, Marine renewable energy, Tidal energy, Wake recovery",
author = "Neary, {Vincent S.} and Budi Gunawan and Craig Hill and Chamorro, {Leonardo P.}",
year = "2013",
month = "12",
day = "1",
doi = "10.1016/j.renene.2013.03.030",
language = "English (US)",
volume = "60",
pages = "1--6",
journal = "Renewable Energy",
issn = "0960-1481",
publisher = "Elsevier BV",

}

TY - JOUR

T1 - Near and far field flow disturbances induced by model hydrokinetic turbine

T2 - ADV and ADP comparison

AU - Neary, Vincent S.

AU - Gunawan, Budi

AU - Hill, Craig

AU - Chamorro, Leonardo P.

PY - 2013/12/1

Y1 - 2013/12/1

N2 - Wake flows downstream of hydrokinetic turbines are characterized by hub and tip vortices, a velocity deficit and an increase in turbulence intensity. Velocity and turbulence recovery in the wakes of individual turbines constrains the density of turbines in an array and limits the amount of energy that can be produced by a turbine farm. However, few hydrokinetic turbine flow recovery studies have been conducted, especially on the far-field flow characteristics. Nor have studies evaluated the accuracy of acoustic Doppler profiler measurements in the wakes of turbines. The present study examines vertical profiles of mean velocity and turbulence, as well as longitudinal profiles of velocity deficit and turbulence levels measured at the symmetry plane of a model three-blade axial flow turbine in a large open channel flow. Mean velocity and turbulence statistics are measured using an acoustic Doppler velocimeter (ADV) and a pulse coherent acoustic Doppler profiler (ADP). ADV and corrected-ADP derived values of mean velocity, turbulence intensity and root-mean-square velocity constitute a well-documented data set that can be used to validate numerical models simulating the effects of hydrokinetic turbine arrays. We found that 80% of the flow recovery occurred about ten diameters downstream from the rotor plane, which suggests that practical values for longitudinal spacing of turbines should be between ten and fifteen diameters. Significant errors observed in mean velocity and turbulence statistics derived from ADP measurements in the near wake region raise concerns on the use of these instruments for such measurements in lab and field studies. Although the cause of some of the errors requires further investigation, we show that errors in turbulence intensity can be successfully corrected with supplemental ADV measurements.

AB - Wake flows downstream of hydrokinetic turbines are characterized by hub and tip vortices, a velocity deficit and an increase in turbulence intensity. Velocity and turbulence recovery in the wakes of individual turbines constrains the density of turbines in an array and limits the amount of energy that can be produced by a turbine farm. However, few hydrokinetic turbine flow recovery studies have been conducted, especially on the far-field flow characteristics. Nor have studies evaluated the accuracy of acoustic Doppler profiler measurements in the wakes of turbines. The present study examines vertical profiles of mean velocity and turbulence, as well as longitudinal profiles of velocity deficit and turbulence levels measured at the symmetry plane of a model three-blade axial flow turbine in a large open channel flow. Mean velocity and turbulence statistics are measured using an acoustic Doppler velocimeter (ADV) and a pulse coherent acoustic Doppler profiler (ADP). ADV and corrected-ADP derived values of mean velocity, turbulence intensity and root-mean-square velocity constitute a well-documented data set that can be used to validate numerical models simulating the effects of hydrokinetic turbine arrays. We found that 80% of the flow recovery occurred about ten diameters downstream from the rotor plane, which suggests that practical values for longitudinal spacing of turbines should be between ten and fifteen diameters. Significant errors observed in mean velocity and turbulence statistics derived from ADP measurements in the near wake region raise concerns on the use of these instruments for such measurements in lab and field studies. Although the cause of some of the errors requires further investigation, we show that errors in turbulence intensity can be successfully corrected with supplemental ADV measurements.

KW - Acoustic Doppler current profiler

KW - Acoustic Doppler velocimeter

KW - Hydrokinetic turbine

KW - Marine renewable energy

KW - Tidal energy

KW - Wake recovery

UR - http://www.scopus.com/inward/record.url?scp=84877336721&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84877336721&partnerID=8YFLogxK

U2 - 10.1016/j.renene.2013.03.030

DO - 10.1016/j.renene.2013.03.030

M3 - Article

AN - SCOPUS:84877336721

VL - 60

SP - 1

EP - 6

JO - Renewable Energy

JF - Renewable Energy

SN - 0960-1481

ER -