On the near-wall effects induced by an axial-flow rotor

N. J. Möller, H. Kim, V. S. Neary, M. H. García, L. P. Chamorro

Research output: Contribution to journalArticle

Abstract

Laboratory experiments were performed to quantify the near-wall flow characteristics and the bed shear stress in the vicinity of an axial-flow rotor model. It was placed in a smooth-wall open channel flow under subcritical conditions and operated at two heights. A laser Doppler velocimeter was used to collect profiles of the streamwise and vertical velocity at few locations within the rotor symmetry plane as close as one wall unit from the bed. Local estimates of the mean bed shear stress were obtained from the mean velocity profiles in the viscous and logarithmic regions. Results show that the bed shear stress is sensitive to the distance from the rotor and to the relative height of the rotor. Maximum bed shear stress occurred downstream of the rotor with the rotor closer to the bed. Flow statistics shows a reduction of turbulence intensity and turbulent shear stress near the wall and close to the rotor due to flow acceleration and changes in the pressure distribution. Spectral analysis of the streamwise velocity evidences a reduction of the energy content across scales spanning two decades right below the turbine. The increase of bed shear is due to mainly flow accelerating but not to turbulence.

Original languageEnglish (US)
Pages (from-to)524-530
Number of pages7
JournalRenewable Energy
Volume91
DOIs
StatePublished - Jun 1 2016

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Axial flow
Rotors
Shear stress
Turbulence
Open channel flow
Laser Doppler velocimeters
Wall flow
Pressure distribution
Spectrum analysis
Turbines
Statistics

Keywords

  • Axial-flow turbines
  • Bed shear stress
  • Channel flow
  • Hydrokinetic energy

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment

Cite this

On the near-wall effects induced by an axial-flow rotor. / Möller, N. J.; Kim, H.; Neary, V. S.; García, M. H.; Chamorro, L. P.

In: Renewable Energy, Vol. 91, 01.06.2016, p. 524-530.

Research output: Contribution to journalArticle

Möller, N. J. ; Kim, H. ; Neary, V. S. ; García, M. H. ; Chamorro, L. P. / On the near-wall effects induced by an axial-flow rotor. In: Renewable Energy. 2016 ; Vol. 91. pp. 524-530.
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