Computer simulations for wind resistance analysis of broadleaf and coniferous forests
Strong winds in nature often cause irreversible damage to trees.Analyzing the airflow inside the forest when strong winds pass through can help assess the wind resistance of trees and comprehensively understand how to mitigate the effects of wind action.Under the premise of taking broadleaf and coniferous trees as prototypes,the characteristics of leaf clusters and branch structures which play a major role in the reconstruction of broadleaf trees and coniferous trees were extracted.The two tree models with different structures were established and formed precisely in order to compose the forest models used in the computer simulations.The computer simulations under wind loading were car-ried out with three different leaf area densities applied to the leaf cluster portion of the tree models.The improved k-e two-equation turbulence model and k-ω two-equation turbulence model were used to set up the wind environment,and the Runge-Kuta method was used to analyze and solve the turbulence model.When the leaf area densities were 1,5 and 10 m2/m3 individually,the minimum wind speed at 20 m on the leeward side of broad-leaf forest decreased by 49.60％,67.23％and 80.40％,and the coniferous forest decreased by 55.13％,68.90％and 78.29％,respectively.When discussing the differences between different models,the k-ω two-equation turbulence model demonstrated more detailed results on the airflow within broadleaf forests than the k-ε two-equation turbulence model.In general,the re-sults showed that the relationship between leaf area density and forest wind resistance was nonlinear.The wind-bloc-king effect of the forest increased with the leaf area density,reducing the rise after reaching a certain extent.Different structures of the tree models lead to changes in the wind field,impacting the probability of damage to trees under same wind loading and the wind-blocking effect of the forest.Concretely speaking,the trees with high leaf area density and large canopy volume were more susceptible to damage in strong winds.The analysis of the various parameters of the forest under wind loading is conducive to quantifying the wind damages of different types of forests,which in turn can help to construct more reasonable windbreak forests.
国家科技期刊平台
NSTL
万方数据
维普
