Effect of drag reducing riblet surface on coherent structure in turbulent boundary layer

Journal article (2019)

Authors

Guangyao CUI Beihang University
C. PAN Beihang University
Di Wu Beihang University
Q. Ye Wind Energy - Aerospace Engineering
Jinjun WANG Beihang University
Research Group
Wind Energy (Aerospace Engineering) (TU Delft)
Copyright: © 2019 Guangyao CUI, C. PAN, Di WU, Q. Ye, Jinjun WANG
DOI: https://doi.org/10.1016/j.cja.2019.04.023
More Info
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Published Date

01-11-2019

Language

English

Faculty

Aerospace Engineering

Department

Flow Physics and Technology

Research Group

Wind Energy

Abstract

The characteristics of turbulent boundary layer over streamwise aligned drag reducing riblet surface under zero-pressure gradient are investigated using particle image velocimetry. The formation and distribution of large-scale coherent structures and their effect on momentum partition are analyzed using two-point correlation and probability density function. Compared with smooth surface, the streamwise riblets reduce the friction velocity and Reynolds stress in the turbulent boundary layer, indicating the drag reduction effect. Strong correlation has been found between the occurrence of hairpin vortices and the momentum distribution. The number and streamwise length scale of hairpin vortices decrease over streamwise riblet surface. The correlation between number of uniform momentum zones and Reynolds number remains the same as smooth surface.