Author(s): G. Caroppi; K. Vastila; J. Jarvela; P. M. Rowinski

Linked Author(s): Kaisa Västilä, Gerardo Caroppi, Juha Järvelä, Pawel M. Rowinski

Keywords: Turbulent flow structure; Partially vegetated channel; Natural-like flexible plants; Foliation effects

Abstract: Experimental investigation in a partly vegetated channel with natural-like flexible plants showed that the mean flow and turbulent flow structures were markedly influenced by the presence of foliation. Across a wide range of environmental settings, vegetation communities occur along rivers in lateral zones parallel to the flow. The lateral interactions between these plant stands and the adjacent main channel affect the turbulent flow structure, influencing e.g. transport of mass, momentum and scalars, such as concentration of sediment, pollutant and nutrients, with relevant biological and ecological implications. Flow in such partially vegetated channels has been commonly analysed by simulating plants as rigid cylinders. Although these studies have increased the understanding of the mixing-layer type flow phenomena, the cylinder representation neglects a variety of flow-influencing mechanisms exhibited by real vegetation. For instance, we expect the flexibility-induced reconfiguration and the complex plant geometries to significantly affect the flow structure and associated mixing processes. The goal of this contribution is to investigate the effects of natural-like emergent vegetation on the flow structure in a partially vegetated channel, with a specific focus on the seasonal variability represented by foliated and leafless conditions.

DOI: https://doi.org/10.3850/978-981-11-2731-1_118-cd

Year: 2018