CFD modelling and wind tunnel validation of airflow through plant canopies using 3D canopy architecture

Endalew, Ayenew Melese; Hertog, Maarten; Delele, Mulugeta Admasu; Baetens, Katrijn; Persoons, Tim; Baelmans, Martine; Ramón, Herman; Nicolaı̈, Bart; Verboven, Pieter

doi:10.1016/j.ijheatfluidflow.2008.12.007

Cited by 92 publications

(44 citation statements)

References 45 publications

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“…In this study, the constants β p and β d , and the closure constants C 4ε and C 5ε are given the values 1.0, 3.0, 1.5, and 1.5, respectively [51][52][53].…”

Section: Simulation Modelsmentioning

confidence: 99%

Prediction of Wind Environment and Indoor/Outdoor Relationships for PM2.5 in Different Building–Tree Grouping Patterns

2018

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Airflow behavior and indoor/outdoor PM 2.5 dispersion in different building-tree grouping patterns depend significantly on the building-tree layouts and orientation towards the prevailing wind. By using a standard k-ε model and a revised generalized drift flux model, this study evaluated airflow fields and indoor/outdoor relationships for PM 2.5 resulting from partly wind-induced natural ventilation in four hypothetical building-tree grouping patterns. Results showed that: (1) Patterns provide a variety of natural ventilation potential that relies on the wind influence, and buildings that deflect wind on the windward facade and separate airflow on the leeward facade have better ventilation potential; (2) Patterns where buildings and trees form a central space and a windward opening side towards the prevailing wind offer the best ventilation conditions; (3) Under the assumption that transported pollution sources are diluted through the inlet, the aerodynamics and deposition effects of trees cause the lower floors of a multi-storey building to be exposed to lower PM 2.5 compared with upper floors, and lower indoor PM 2.5 values were found close to the tree canopy; (4) Wind pressure differences across each flat showed a poor correlation (R 2 = 0.059), with indoor PM 2.5 concentrations; and (5) Patterns with the long facade of buildings and trees perpendicular to the prevailing wind have the lowest indoor PM 2.5 concentrations.

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“…In this study, the constants β p and β d , and the closure constants C 4ε and C 5ε are given the values 1.0, 3.0, 1.5, and 1.5, respectively [51][52][53].…”

Section: Simulation Modelsmentioning

confidence: 99%

Prediction of Wind Environment and Indoor/Outdoor Relationships for PM2.5 in Different Building–Tree Grouping Patterns

2018

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“…Endalew attempted to establish a more detailed model of trees, proposed establishing trunk and branches according to the real situation, only the leaves were modeled as porous regions, comparative analysis shows that this method is inefficient and gets a similar wake region wind field with the method described above. 13 The study showed that the additional source term method is an efficient way to simulate windbreak performance of trees.…”

Section: Introductionmentioning

confidence: 99%

Study on windbreak performance of tree canopy by numerical simulation method

Zhang

Wang

2018

The Journal of Computational Multiphase Flows

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When airflow fly over trees, a shelter area will be generated at downstream area, and wind speed in the region will be reduced correspondingly. In order to analyze the windbreak performance of tree canopy, porous media method and additional source term are explored to simulate by computational fluid dynamics. Based on the given method, windbreak performance of trees with different canopy porosity, canopy shapes and distances between trees is investigated in detail, and characteristics of wind flow on the downstream of tree are shown. Results showed that small canopy porosity does not always mean good performance of windbreak, especially for the lower part. Canopy shapes only affect wind speed in the wake range. In these regions, windbreak performance of tree depends on the thickness of canopy. When distance is beyond 3H (H is the height of tree), wind speed becomes uniform at the downstream of tree and spacing can be equivalent to the porosity. But, for the region close to tree, trees with spacing cannot provide effective windshield. These simulations of tree canopy windbreak performance are conducted. All the results of the new model show better canopy flow characteristics through the field.

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“…Recently, Melese Endalew et al (2009) conducted an elaborate experimental and 3-D numerical study of the flow over a single tree. In addition to the standard homogeneous porous model of the canopy, they also built a very complex model of the tree including its branches.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Airflow Across Trees in a Windbreak

Rosenfeld

Marom

Bitan

2010

Boundary-Layer Meteorol

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The flow across a three-dimensional (3-D) windbreak comprising individual cypress trees is studied to establish the significance and extent of the 3-D flow patterns. The cypress tree is modelled as a solid cylindrical stem and a conic porous canopy. Cases with a single row of trees or two rows of trees with different distances between the rows are considered; in the case of a single row, several densities of the canopy are used. The steady Reynoldsaveraged Navier-Stokes (RANS) approximation is solved using a commercial computational fluid dynamics (CFD) package and a high-resolution mesh. Three-dimensional flow is found in the vicinity of the windbreak up to a leeward distance of 1-2 tree-heights, depending on the density of the canopy, and is manifest as significant lateral variations and reduced vertical flow. At larger leeward distances, a two-dimensional (2-D) flow is established with characteristics similar to existing 2-D studies; the flow leeward of the last row is insensitive to the distance between the rows. Homogeneous 2-D windbreak models are found to be inaccurate in the vicinity of the windbreak. This is exactly the region that needs to be sheltered in many cases, since the inner vegetation is anyway protected by the outer vegetation.

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CFD modelling and wind tunnel validation of airflow through plant canopies using 3D canopy architecture

Cited by 92 publications

References 45 publications

Prediction of Wind Environment and Indoor/Outdoor Relationships for PM2.5 in Different Building–Tree Grouping Patterns

Prediction of Wind Environment and Indoor/Outdoor Relationships for PM2.5 in Different Building–Tree Grouping Patterns

Study on windbreak performance of tree canopy by numerical simulation method

Numerical Simulation of the Airflow Across Trees in a Windbreak

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