山区大气扩散风场及浓度场的数值模拟

Numerical Simulation for Atmospheric Diffusion Wind and Concentration Field in Mountain Area

本文依据一个同时包括地形,热力以及摩擦等因素在内的,能够较真实地反映复杂地形下,大气运动基本特征的近地层水平流场二维数值模式,将其扩展成三维模式,在此基础上,从平流扩散方程出发,建立了一个与上述流场相应的浓度场予报模式。利用长寿化工厂及附近的地形和污染等有关资料进行了浓度场分布的计算,并与实测资料作了比较得到较好的结果。山区复杂地形条件下,大气污染浓度分布的数值模拟包括两个部份的工作,第一部份是在一定的大尺度大气背景流场下模拟由于地形的热力和动力因素造成的局地流场,以及相应的湍流场,第二部份是在上述流场的基础上模拟污染物的输送规律。显然,第一部份的工作是解决大气污染物浓度分布数值模拟的基础。本文结合长寿化工厂的环境评价工作,对复杂地形下的三维流场的浓度场的数值模拟作了一些研究工作,主要以浓度场的模拟为主。

This paper takes into consideration many factors such as topography,thermodimamic property, friction and so on.It develops the two-dimentional numerical model about the horizontal flow tield of ground layer into three-dimentional space model,so that it can really show the basic features of atmospheric movement in complex terrains.According to the advection-diffusion equation,we set up a concentration field prediction model which suits the flow field.In consideration of topography, pollution and other basic informations,we calculate the concentration field and compare its results with practical measurement.Tth results are quite good. In the mountain's complex terrains,the numerical simulation for atmospheric pollution concentration field consists of two parts of simulation.The first is that topography,thermodynamic property and kinetics bring about the local flow field and the turbulent flow ficld on a large scale of atmospheric flow field,The second simulation gives the pollution transfer rule on the basis of the above mentioned flow field.The first numerical simulation solves the atmospheric pollution concentration field.Considering the program of environmental influerice evaluation about Changshou Chemical Plant in Sichuan,we have studied the nrmerical simulation for three-dimentional wind and concentration field in complex terracns.