林带透风系数与湍流度关系的风洞试验研究

Study on the Relationship Between Ventilation Coefficient of Shelterbelt and Turbulence Scale

林带降低风速最根本的问题是在林带背风面形成湍流,湍流的变化与透风系数紧密相关。所以探讨林带的透风系数与湍流度的变化是农田防护林网气象效应的一个重要方面。本文应用二次回归正交旋转组合设计的方法,通过风洞实验和计算建立了透风系数与湍流度之间的回归模型方程。利用该方程可对林带背风面不同高度的透风系数和湍流度相互进行预测,并揭示了两者之间内在的相关关系。同时利用本文的回归模型方程,用最篷透风系数可预测最适湍流度,并对了解林带背风面不同高度上湍流度的变化有重大意义。

The fundamental problem for a shelterbelt to reduce windspced is to form turbulence on the lee of the shelterbelt.The change of turbulence scale is colscly reared to ventilation coefficient.To explore the change of ventilation coefficient of a shelterbelt and its turbulence scale is an important aspect of studying on thc atmospheric effcet of shelterbelt for farmland.The design method of orthogonal rotation combinations with a curvilincar regression was used,the model equation between ventilation coefficient and tur- bulence scale is established through windtunncl experiment aand computation.This cqua- tion makes it possiblc to previse bilaterally the ventilation coefficients and turoulence scales at different heights on the lee of a shclterbelt and to revcal the internal corrclation between the ventilation coefficients and turbulence scales.Also by this equation it is possible to prcvise optimal turbulence scalcs with optimal ventilation coeffieients and it is helpful to realize thc changes of turbulence scales at different heights on the lee of a shelterbelt.