This paper reviews various urban tree modelling tools in Computational Fluid Dynamics (CFD) and their applicability to urban greenery management. Recent developments in computational fluid dynamics as well as experimental studies have sought to understand the complex and dynamic wind-tree interaction phenomena in order to estimate the aerodynamic force that trees can endure in given locations, and assess the tree management scenario and risk of tree failure. Wind-tree interactions have been modelled using several methods such as roughness lengths, immersed boundary layer, porous media and explicit modelling methods. The most widely adopted method is the porous media model which provides a reasonable level of accuracy at affordable computational cost. Porous media models parametrize the relationship between trees and air flow using various tree characteristics such as tree frontal area, leaf area density and drag coefficients. Studies that detail how these properties can be measured using various methods in wind tunnels and on the field are discussed. Various groups have also done large-scale urban CFD studies which include the effects of urban vegetation on wind patterns. Intervention in the form of pruning is required when trees with high risk of failure are identified hence research on the effects of pruning on these characteristics are also detailed. This review paper details the recent works as well as gaps in knowledge on tree dynamics, numerical and experimental modelling of urban vegetation and its potential applications in greenery management in metropolitan areas.
License type:
http://creativecommons.org/licenses/by-nc-nd/4.0/
Funding Info:
The authors gratefully acknowledge the financial support of the research grant under Virtual Singapore
Programme (NRF2017VSG-AT3DCM001-029) from the National Research Foundation of Singapore.