skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Flow adjustment inside homogeneous canopies after a leading edge – An analytical approach backed by LES

Abstract

A two-dimensional analytical model for describing the mean flow behavior inside a vegetation canopy after a leading edge in neutral conditions was developed and tested by means of large eddy simulations (LES) employing the LES code PALM. The analytical model is developed for the region directly after the canopy edge, the adjustment region, where one-dimensional canopy models fail due to the sharp change in roughness. The derivation of this adjustment region model is based on an analytic solution of the two-dimensional Reynolds averaged Navier–Stokes equation in neutral conditions for a canopy with constant plant area density (PAD). The main assumptions for solving the governing equations are separability of the velocity components concerning the spatial variables and the neglection of the Reynolds stress gradients. These two assumptions are verified by means of LES. To determine the emerging model parameters, a simultaneous fitting scheme was applied to the velocity and pressure data of a reference LES simulation. Furthermore a sensitivity analysis of the adjustment region model, equipped with the previously calculated parameters, was performed varying the three relevant length, the canopy height ( h), the canopy length and the adjustment length ( Lc), in additional LES. Even if the model parameters are,more » in general, functions of h/ Lc, it was found out that the model is capable of predicting the flow quantities in various cases, when using constant parameters. Subsequently the adjustment region model is combined with the one-dimensional model of Massman, which is applicable for the interior of the canopy, to attain an analytical model capable of describing the mean flow for the full canopy domain. As a result, the model is tested against an analytical model based on a linearization approach.« less

Authors:
 [1]; ORCiD logo [2];  [1];  [1]
  1. Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen (Germany)
  2. Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen (Germany); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
DFG; German Research Foundation (DFG); USDOE
OSTI Identifier:
1402664
Report Number(s):
LA-UR-17-29139
Journal ID: ISSN 0168-1923
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Agricultural and Forest Meteorology
Additional Journal Information:
Journal Volume: 255; Journal ID: ISSN 0168-1923
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; Earth Sciences; canopy edge; analytical model; adjustment region; large eddy simulations

Citation Formats

Kroniger, Konstantin, Banerjee, Tirtha, De Roo, Frederik, and Mauder, Matthias. Flow adjustment inside homogeneous canopies after a leading edge – An analytical approach backed by LES. United States: N. p., 2017. Web. doi:10.1016/j.agrformet.2017.09.019.
Kroniger, Konstantin, Banerjee, Tirtha, De Roo, Frederik, & Mauder, Matthias. Flow adjustment inside homogeneous canopies after a leading edge – An analytical approach backed by LES. United States. doi:10.1016/j.agrformet.2017.09.019.
Kroniger, Konstantin, Banerjee, Tirtha, De Roo, Frederik, and Mauder, Matthias. Fri . "Flow adjustment inside homogeneous canopies after a leading edge – An analytical approach backed by LES". United States. doi:10.1016/j.agrformet.2017.09.019.
@article{osti_1402664,
title = {Flow adjustment inside homogeneous canopies after a leading edge – An analytical approach backed by LES},
author = {Kroniger, Konstantin and Banerjee, Tirtha and De Roo, Frederik and Mauder, Matthias},
abstractNote = {A two-dimensional analytical model for describing the mean flow behavior inside a vegetation canopy after a leading edge in neutral conditions was developed and tested by means of large eddy simulations (LES) employing the LES code PALM. The analytical model is developed for the region directly after the canopy edge, the adjustment region, where one-dimensional canopy models fail due to the sharp change in roughness. The derivation of this adjustment region model is based on an analytic solution of the two-dimensional Reynolds averaged Navier–Stokes equation in neutral conditions for a canopy with constant plant area density (PAD). The main assumptions for solving the governing equations are separability of the velocity components concerning the spatial variables and the neglection of the Reynolds stress gradients. These two assumptions are verified by means of LES. To determine the emerging model parameters, a simultaneous fitting scheme was applied to the velocity and pressure data of a reference LES simulation. Furthermore a sensitivity analysis of the adjustment region model, equipped with the previously calculated parameters, was performed varying the three relevant length, the canopy height (h), the canopy length and the adjustment length (Lc), in additional LES. Even if the model parameters are, in general, functions of h/Lc, it was found out that the model is capable of predicting the flow quantities in various cases, when using constant parameters. Subsequently the adjustment region model is combined with the one-dimensional model of Massman, which is applicable for the interior of the canopy, to attain an analytical model capable of describing the mean flow for the full canopy domain. As a result, the model is tested against an analytical model based on a linearization approach.},
doi = {10.1016/j.agrformet.2017.09.019},
journal = {Agricultural and Forest Meteorology},
number = ,
volume = 255,
place = {United States},
year = {Fri Oct 06 00:00:00 EDT 2017},
month = {Fri Oct 06 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on October 6, 2018
Publisher's Version of Record

Save / Share: