scholarly journals An Advanced Multiple‐Layer Canopy Model in the WRF Model With Large‐Eddy Simulations to Simulate Canopy Flows and Scalar Transport Under Different Stability Conditions

2019 ◽  
Vol 11 (7) ◽  
pp. 2330-2351 ◽  
Author(s):  
Yulong Ma ◽  
Heping Liu
Keyword(s):  
Wrf Model ◽  
Large Eddy Simulations ◽  
Scalar Transport ◽  
Stability Conditions ◽  
Multiple Layer ◽  
Large Eddy ◽  
Canopy Flows ◽  
Canopy Model

scholarly journals Evaluation of the the wind farm wake parametrization with large-eddy simulations of wakes in WRF

2021 ◽  
Author(s):  
Alfredo Peña ◽  
Jeffrey Mirocha
Keyword(s):  
Boundary Layer ◽  
Wind Farm ◽  
Wrf Model ◽  
Wind Farms ◽  
Large Eddy Simulations ◽  
Disk Model ◽  
Mesoscale Models ◽  
Boundary Layer Height ◽  
Wind Speeds ◽  
Large Eddy

<p>Mesoscale models, such as the Weather Research and Forecasting (WRF) model, are now commonly used to predict wind resources, and in recent years their outputs are being used as inputs to wake models for the prediction of the production of wind farms. Also, wind farm parametrizations have been implemented in the mesoscale models but their accuracy to reproduce wind speeds and turbulent kinetic energy fields within and around wind farms is yet unknown. This is partly because they have been evaluated against wind farm power measurements directly and, generally, a lack of high-quality observations of the wind field around large wind farms. Here, we evaluate the in-built wind farm parametrization of the WRF model, the so-called Fitch scheme that works together with the MYNN2 planetary boundary layer (PBL) scheme against large-eddy simulations (LES) of wakes using a generalized actuator disk model, which was also implemented within the same WRF version. After setting both types of simulations as similar as possible so that the inflow conditions are nearly identical, preliminary results show that the velocity deficits can differ up to 50% within the same area (determined by the resolution of the mesoscale run) where the turbine is placed. In contrast, within that same area, the turbine-generated TKE is nearly identical in both simulations. We also prepare an analysis of the sensitivity of the results to the inflow wind conditions, horizontal grid resolution of both the LES and the PBL run, number of turbines within the mesoscale grid cells, surface roughness, inversion strength, and boundary-layer height.</p>

scholarly journals Large-Eddy Simulations of Inhomogeneous Canopy Flows

PAMM ◽  
2010 ◽  
Vol 10 (1) ◽  
pp. 453-454
Author(s):  
Fabian Schlegel ◽  
Jörg Stiller
Keyword(s):  
Large Eddy Simulations ◽  
Large Eddy ◽  
Canopy Flows

Mixing dynamics in an uncovered unbaffled stirred tank using Large-Eddy Simulations and a passive scalar transport equation

2020 ◽  
Vol 222 ◽  
pp. 115658
Author(s):  
J. Ramírez-Cruz ◽  
M. Salinas-Vázquez ◽  
G. Ascanio ◽  
W. Vicente-Rodríguez ◽  
C. Lagarza-Córtes
Keyword(s):  
Transport Equation ◽  
Passive Scalar ◽  
Large Eddy Simulations ◽  
Scalar Transport ◽  
Stirred Tank ◽  
Passive Scalar Transport ◽  
Large Eddy ◽  
Mixing Dynamics

Using a Canopy Model Framework to Improve Large-Eddy Simulations of the Neutral Atmospheric Boundary Layer in the Weather Research and Forecasting Model

2019 ◽  
Vol 147 (1) ◽  
pp. 31-52 ◽  
Author(s):  
Robert S. Arthur ◽  
Jeffrey D. Mirocha ◽  
Katherine A. Lundquist ◽  
Robert L. Street
Keyword(s):  
Boundary Layer ◽  
Boundary Condition ◽  
Large Eddy Simulations ◽  
Weather Research And Forecasting ◽  
Forecasting Model ◽  
Model Framework ◽  
Roughness Elements ◽  
Large Eddy ◽  
Log Law ◽  
Canopy Model

A canopy model framework is implemented in the Weather Research and Forecasting Model to improve the accuracy of large-eddy simulations (LES) of the atmospheric boundary layer (ABL). The model includes two options that depend on the scale of surface roughness elements. A resolved canopy model, typically used to model flow through vegetation canopies, is employed when roughness elements are resolved by the vertical LES grid. In the case of unresolved roughness, a modified “pseudocanopy model” is developed to distribute drag over a shallow layer above the surface. Both canopy model options are validated against idealized test cases in neutral stability conditions and are shown to improve surface layer velocity profiles relative to simulations employing Monin–Obukhov similarity theory (MOST), which is commonly used as a surface boundary condition in ABL models. Use of the canopy model framework also leads to increased levels of resolved turbulence kinetic energy and turbulent stresses. Because LES of the ABL has a well-known difficulty recovering the expected logarithmic velocity profile (log law) in the surface layer, particular focus is placed on using the pseudocanopy model to alleviate this issue over a range of model configurations. Tests with varying surface roughness values, LES closures, and grid aspect ratios confirm that the pseudocanopy model generally improves log-law agreement relative to simulations that employ a standard MOST boundary condition. The canopy model framework thus represents a low-cost, easy-to-implement method for improving LES of the ABL.

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