Abstract:
The tree-like canopy model,formed by crown and trunk,are conducted in laboratory flow experiments. MicroADV are used to study the flow characteristics influenced by vegetation with ball-like canopy in open channel. Flow condition varied in four cases,with different flow rate and water depth. Focusing on the mean velocity and turbulence structure, the vertical profiles of longitudinal velocity, vertical velocity and turbulence intensity were analyzed. The results show that the normalized longitudinal velocity increases as the water depth decreases. The longitudinal velocity is almost constant in the stem layer. It decreases firstly then increases with increment of depth in the canopy layer. Strong fluctuation of turbulence intensity is found in the canopy layer. The longitudinal velocity in no-canopy layer follows logarithmic law. The quadrant analysis recovers the canopy layer is the sweep-dominated area and no-canopy layer is the ejection-dominated area.
«