A new algebraic subgrid-scale model for flow over and within vegetation canopies
Abstract
The interaction between the airflow and vegetation canopies profoundly modifies the structure of boundary-layer turbulence, impacting transfer rates of mass, momentum and energy in the roughness sublayer. Smagorinsky-type subgird-scale (SGS) closures assume local equilibrium between shear production and viscous dissipation of SGS kinetic energy, and do not account for the impact of canopy-wake motions on such a budget. However, contributions from wake production and dissipation on SGS energetics can be significant, which is evidenced by available SGS kinetic energy budgets from large-eddy simulations based on one-equation models.In this study, we propose a new algebraic subgrid-scale closure model that accounts for the impact of wake motions on the subgrid-scale viscosity, by modifying the dominant balance in the local equilibrium assumption of the SGS energy budget. Predictions from the newly proposed subgrid-scale model are compared with those from a one equation closure model and experimental measurements of flow over a homogeneous canopy and a forest-edge.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A54B..06L
- Keywords:
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- 0315 Biosphere/atmosphere interactions;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 3307 Boundary layer processes;
- ATMOSPHERIC PROCESSESDE: 3322 Land/atmosphere interactions;
- ATMOSPHERIC PROCESSESDE: 3379 Turbulence;
- ATMOSPHERIC PROCESSES