Impacts of Plant Deformation on Particle Transport in Turbulent Canopy Flows
Abstract
Flexible plants bend and streamline in response to flows, allowing plants to minimize the increase of drag force with increasing velocity and ensuring survival in flow-dominated habitats. This deformation mechanism has been observed over a wide variety of vegetation, including freshwater plants, seaweeds, reeds, grasses, agricultural crops, and trees. In turbulent canopy flows, the passage of canopy-shear-layer vortices lead to wavelike propagation of plant deformation known as honami or monami. Theoretical and observational studies suggest that the effect of plant deformation can be characterized by a power-law decrease in drag coefficient with increasing velocity. In this work we show that introducing a velocity-dependent drag coefficient enables large-eddy simulation (LES) to reproduce the third-order turbulence statistics and the probability distribution of upward and downward events. The deformation of individual plants in response to the passage of canopy-shear-layer vortices has negligible impacts on total momentum flux and turbulent kinetic energy, but it produces profound changes in events that transport momentum, scalars, and particles. Flume and field experimental data of both aquatic and terrestrial turbulent canopy flows have confirmed LES findings. This work demonstrates the necessity to account for the effect of plant deformation in studying turbulent canopy flows, highlighting the connection between high-order turbulence statistics and transport events.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMEP41A..01P
- Keywords:
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- 0498 General or miscellaneous;
- BIOGEOSCIENCESDE: 1813 Eco-hydrology;
- HYDROLOGYDE: 1894 Instruments and techniques: modeling;
- HYDROLOGYDE: 1895 Instruments and techniques: monitoring;
- HYDROLOGY