Three-Dimensional Flow Characteristics in A Channel with Emergent Rigid Vegetation

Abstract

Various flow characteristics such as velocity distributions, turbulence characteristics, mass and momentum exchange between the vegetated and non-vegetated regions. Aquatic plants are responsible for reducing sediment transport, erosion control and turbidity, water quality, nutrient and particulate removal significantly. The studying and understanding of the vegetation effect on the natural flow is an important objective in modern scientific research about flow structure, flood control, river restoration and management with high environmental impact. Therefore, in the present study, the effect of emergent rigid vegetation with staggered configuration in an open channel is studied through a straight rectangular flume experiment. Three-dimensional vertical distribution of velocity, turbulence intensity, and Reynolds shear stress for vegetated and non-vegetated area is analyzed and compared between them. The results show that the streamwise, lateral and vertical velocity are found to be smaller, higher with negative magnitude and smaller, respectively within the vegetated area than the nonvegetated area. Near the bed surface, a strong upward velocity present in the vegetation area and decreasing towards upper surface. Streamwise and lateral turbulence intensities are stronger for vegetation area. Three-dimensional Reynolds shear stress and turbulent kinetic energy are also evaluated in this study. This experiment provides a vital interpretation to understand flow characteristics in non-vegetation and vegetation area.