Wake flow field of a wall-mounted pipe with spoiler on a rough channel bed

• Published in: Acta geophysica Vol. 71; no. 6; pp. 2865 - 2881
• Main Authors: Devi, Kalpana, Mishra, Shivam, Hanmaiahgari, Prashanth Reddy, Pu, Jaan H.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.12.2023; Springer Nature B.V
• Subjects: Cylinders; Earth and Environmental Science; Earth Sciences; Flow velocity; Fluid flow; Free surfaces; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Hole size; Kinetic energy; Normal stress; Research Article - Hydrology; Reynolds number; River beds; Shear layers; Shear stress; Skewed distributions; Steady flow; Structural Geology; Surface flow; Turbulence; Turbulence intensities; Turbulent flow; Turbulent kinetic energy; Velocimetry; Velocity distribution; Wake effects; Turbulence; Quadrant analysis; ADV; Spoiler; Bed-mounted horizontal cylinder; Wake region
• ISSN: 1895-7455; 1895-6572; 1895-7455
• DOI: 10.1007/s11600-022-01008-x

This research work focuses on the wake flow region of a cylinder with a spoiler on a rough bed under steady flow conditions. The acoustic Doppler velocimetry was used for the measurement of three-dimensional velocity data for two Reynolds numbers in a fully developed turbulent flow around the cylinder with a spoiler. The mean flow velocities, second-order turbulence structures, and conditional statistics were investigated in the wake region of the spoilered cylinder. The flow was separated from the spoiler with the formation of two shear layers between free surface flow and recirculating flow. It is observed that the flow is reattaching to the bed at 11 D irrespective of the Reynolds number . Downstream of the cylinder, the mean velocity distributions are asymmetric due to the wall–wake effect, and the point of inflection is observed for each velocity profile at z  = 0.40 ẟ . The turbulence intensities, Reynolds stresses, and TKE are highly enhanced in the wake region of the cylinder as compared to their respective upstream values for both runs. The turbulence intensities, Reynolds normal stresses, Reynolds shear stresses, and turbulent kinetic energy are attaining peaks at z  = 0.4  ẟ for all the streamwise locations, and the peaks are found to be highest at x  = 10 D . The quadrant analysis results indicate that the sweeps are dominating bursting events in the inner and intermediate layers, while ejections are dominating in the outer layer of the wake region. As the hole size, H increases ejections stress fraction rises as compared to that of the sweeps in the wake region for z  = 0.2–0.7 h.