Mean flow

Compare of mean velocity profiles at different spanwise locations from both stereo PIV and low resolution PIV measurement

Turbulence Statistics

Compare of mean velocity profiles at different spanwise locations from both stereo PIV and low resolution PIV measurement

High order moments.

• Ejection events dominate in most portion of the channel.
• Cross-over of the KTE transport occurs within the roughness sublayer.
• KTE transport reaches maxima around 0.5h.

Turbulence Structures

TKE energy spectra

• Signature of roughness exists very near the wall.
• Substantial variation of turbulent energy at scale < l, occurs only within 5k.
• Spanwise influences diminish above 2k for current scale span.

Quadrant contribution to the Reynolds shear stress

• Deviations among filtered field indicates the inadequacy of the current resolution.
• Q2 events extend beyond 0.5h, Q4 events are compressed within 1k.
• Substantial disparity only occur very near the wall.