用于建筑绕流预测的非线性涡粘模型改良

Improvement of the non-linear eddy viscosity model applied to predicting wind flow around building

为了改良非线性涡粘性模型模拟建筑绕流问题的表现,首先介绍了采用涡粘性模型预测建筑绕流问题的现状,分析了模拟中存在的问题,然后基于Craft非线性涡粘性模型提出了一种用于预测建筑绕流的改良的非线性涡粘性模型,并利用日本建筑学会提供的风洞实验数据对改良的非线性模型进行分析验证.结果表明:改良的非线性涡粘性模型一方面改善了标准k-ε模型建筑前端湍动动能预测过大的问题,预测出了建筑顶部的分离和再附着;另一方面通过增大尾迹区的湍动动能,改善了涡粘性模型在预测建筑尾迹区流动中的表现.通过改良,非线性涡粘性模型可以较好地预测建筑风环境.

The aim of this paper is to improve the performance of the non-linear eddy viscosity model for simulating the wind flow around the building. Firstly, the state of art of the predicting wind flow around building using RANS model was introduced, and the problems in the simulation were analyzed. Then an improved non-linear eddy viscosity for predicting the wind flow around buildings was proposed based on Craft model. The improved non-linear eddy viscosity was validated and analyzed through the wind tunnel data provided by AIJ. The results showed that the proposed non-linear eddy viscosity improved the overestimation of turbulent kinetic energy in impingement region by the standard k - ε model, and predicted better results in the wake region behind buildings simultaneously through strengthening the eddy viscosity in the wake region. After the improvement, the non-linear eddy viscosity model can predict the wind environment around buildings better.