Flow field downstream of individual aquatic plants—Experiments in a natural river with Potamogeton crispus L. and Myriophyllum spicatum L.

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • Institute of Geophysics of the Polish Academy of Sciences

Abstract

Flow disturbances generated by individual patches of submerged, flexible aquatic vegetation were investigated for two naturally growing macrophyte species, Potamogeton crispus L. and Myriophyllum spicatum L., in a sandy lowland river. Through acoustic Doppler velocimetry, 24 vertical profiles of the 3D velocity field were recorded downstream of each of the patches. The morphological features and biomechanical properties of the plants were also evaluated. The experiments showed the relationship between biomechanical characteristics and turbulence statistics. M. spicatum, which was stiffer and therefore less prone to dynamic reconfiguration, showed a greater effect on velocity damping, causing an increase in Reynold stresses, turbulence intensities, and turbulent kinetic energy downstream of the patch. These effects were present in regions both above and below plant height. In contrast for P. crispus, these effects were present only below plant height. The stiffer plant produced a mixing layer in its wake similar to that of dense plant canopies. The patch of less stiff and more streamlined P. crispus with longer leaves presented a much weaker effect on the flow. In contrast to previous studies conducted with rigid plant surrogates, we concluded that reconfiguration of the living flexible plants allows the plants to minimize drag forces, and therefore, their influence on the flow field was weaker than the effects reported for rigid surrogates.

Details

Original languageEnglish
Pages (from-to)1324-1337
Number of pages14
JournalHydrological Prosesses
Volume33
Issue number9
Early online date21 Feb 2019
Publication statusPublished - 30 Apr 2019
MoE publication typeA1 Journal article-refereed

    Research areas

  • acoustic Doppler velocimetry, aquatic plants, biomechanical properties, flexible vegetation, reconfiguration, turbulence, turbulent kinetic energy, velocity field

ID: 32940866