TITLE:
Effects of Rigid Vegetation on the Turbulence Characteristics in Sediment-Laden Flows
AUTHORS:
Shengqi Lu, Jieren Chen
KEYWORDS:
Rigid Vegetation, Turbulence Characteristics, Sediment-Laden Flow, Experimental Study
JOURNAL NAME:
Journal of Applied Mathematics and Physics,
Vol.2 No.12,
November
25,
2014
ABSTRACT: The effects of rigid vegetation on the
turbulence characteristics were experimentally studied in the interior water
flume. An ADV was used to determine the three dimensional turbulent velocities
in clear water flow without vegetation, sediment-laden flow without vegetation,
sediment-laden flow with submerged vegetation and sediment-laden flow with
non-submerged vegetation. By experimental and theoretical analysis, the effects
of rigid vegetation on the distribution of averaged velocities, turbulence
intensities and Reynolds stress were summarized. In sediment-laden flow with submerged
vegetation, the averaged stream wise velocities above the top of vegetation fit
well with the log distribution low. The three-dimensional turbulence
intensities increase from the bottom until they reach the maximum at the top of
the vegetation. The method to calculate the shear velocity with the maximum of
the Reynolds stress is recommended. In sediment-laden flow with non-submerged
vegetation, the turbulence problems cannot be explained by theory of bed shear
flow. The average velocities, turbulence intensities and Reynolds stress approximate
uniformly distributed along vertical direction.