Author(s): Shuang Gao; Tadaharu Ishikawa; Yi Zhang
Linked Author(s):
Keywords: Constructed wetland; Artificial short circuit; Particle-image velocimetry; Numerical simulation; Kelvin-Helmholts vortices; Suspended solid
Abstract: This paper discusses suspended solid (SS) transport by Kelvin-Helmholts (K-H) vortices from a narrow channel to surrounding vegetation areas in a constructed wetland. A series of flume experiments were carried out for several conditions of width/depth ratio and Reynolds number, referring to the ranges of the parameters reported in an actual constructed wetland. The unsteady velocity field was measured in detail using the PIV technique. Numerical simulations were conducted under the same conditions as the experiments, and computational results agreed well with observed results. The study clarified the dependence of K-H vortices scale and intensity on the two parameters mentioned above. Numerical tracer experiments were conducted to investigate the basic characteristics of SS transport by K-H vortices. The results showed that the range of SS intrusion into vegetation areas is comparable to channel width. This suggests that a system of channels should be designed to distribute SS over a wide area of vegetation in a constructed wetland.
Year: 2012