Skip to Main content Skip to Navigation
Journal articles

Pressure-Gradient Forcing Methods for Large-Eddy Simulations of Flows in the Lower Atmospheric Boundary Layer

Abstract : Turbulent flows over forest canopies have been successfully modeled using Large-Eddy Simulations (LES). Simulated winds result from the balance between a simplified pressure gradient forcing (e.g., a constant pressure-gradient or a canonical Ekman balance) and the dissipation of momentum, due to vegetation drag. Little attention has been paid to the impacts of these forcing methods on flow features, despite practical challenges and unrealistic features, such as establishing stationary velocity or streak locking. This study presents a technique for capturing the effects of a pressure-gradient force (PGF), associated with atmospheric patterns much larger than the computational domain for idealized simulations of near-surface phenomena. Four variants of this new PGF are compared to existing forcings, for turbulence statistics, spectra, and temporal averages of flow fields. Results demonstrate that most features of the turbulent flow are captured. The variants can either enable modelers to prescribe a wind speed and direction at a reference height close to the ground as required in wildfire simulations, and/or mitigate streaks locking by reproducing the stability of the Ekman balance. Conditions of use, benefits, and drawbacks are discussed. PGF approaches, therefore, provide a viable solution for precursor inflows, including for the specific domains used in fire simulations.
Document type :
Journal articles
Complete list of metadata

https://hal.inrae.fr/hal-03165727
Contributor : Nelly Lucas <>
Submitted on : Wednesday, March 10, 2021 - 7:59:09 PM
Last modification on : Friday, April 9, 2021 - 9:16:05 AM

Links full text

Identifiers

Collections

Citation

François Pimont, Jean-Luc Dupuy, Rodman Linn, Jeremy Sauer, Domingo Muñoz-Esparza. Pressure-Gradient Forcing Methods for Large-Eddy Simulations of Flows in the Lower Atmospheric Boundary Layer. Atmosphere, MDPI 2020, 11 (12), pp.1343. ⟨10.3390/atmos11121343⟩. ⟨hal-03165727⟩

Share

Metrics

Record views

11