Author(s): Amir Mehdi Razmi; Marcelo Chamecki; Heidi Margaret Nepf
Linked Author(s): Heidi M. Nepf
Keywords: Distributed drag force; Flexible vegetation; Monami; Plant–flow interaction; Reconfiguration; Turbulence
Abstract: This study considered a new approach for representing flexible canopies within large-eddy simulation that captures the impacts of reconfiguration on both the canopy posture and the canopy drag. The unsteady change in plant posture in response to the passage of turbulence structures ( monami ) was assessed using established steady-reconfiguration models responding to the unsteady velocity at the top of the canopy. The new drag and plant posture models improved the modelling of highly flexible canopies by more accurately capturing the observed vertical distribution of peak Reynolds stress. When compared to models that do not consider reconfiguration, or that represent it only through a velocity-dependent drag coefficient, the addition of a velocity-dependent canopy posture (unsteady reconfiguration) achieved up to a 56% reduction of the root mean square error for mean horizontal flow velocity and Reynolds stress profiles over the canopy. The RMSE for turbulence intensities and skewness were reduced up to 48% and 56%, respectively.