基于数值模拟的橡胶防护林防风效应探讨

Study on Windbreak Effect of Rubber and Protection Forest Based on Numerical Simulation

针对影响防风效应的多种因素,对大风绕橡胶及防护林带的流场进行数值模拟。将林带视为符合空气动力特性的多孔介质模型,通过分析林带内部结构对绕林流场的影响,构建林带二维模型。在k-ε控制方程的基础上,对相关参数进行修正,借助CFD软件模拟了大风绕林后的流场。比较了2种流场中的沿流相对风速的变化,并对模拟进行了验证分析。结果表明,3种树高下的防护林带后的防护距离差别不明显,且树越高,承受的风压越大;相比通风型林带,紧密型和疏透型林带防护效果更好。这也为橡胶及防护林的矮化密植提供试验依据。

According to the factors affecting the windbreak effect, the flow field around rubber plantations and shelterbelts were simulated. Firstly, the forest was regarded as porous medium model with aerodynamic characteristics. Through the analysis of the internal structure of the belt to influence around the forest field,two-dimensional model was built. Secondly based on the k-ε equations, the relevant parameters were amended,and the wind flow field around the forest was simulated with CFD software. Finally,the changes of relative wind velocity along the flow in two kinds of flow field and the simulation were compared. The results showed that the differences of protection distance in the three tree heights of shelterbelt were not significant, and the higher a tree was, the more pressure suffered. Compared to the ventilation type belt, the protection effect of close type and sparse through type forest were better. The results would provide an ex- perimental basis for rubber plantation and protection forest dwarfing and close planting.