中文摘要：

作为自然界的一种强风荷载，雷暴天气产生的下击暴流风在世界范围内造成了大量工程结构物的破坏。研究证实，下击暴流风具有同常规的大气边界层近地风完全不同的风场特征。利用通用商业CFD（Computational fluid dynamics）软件FLUENT完成了几何缩尺比为1：2000的下击暴流过程的数值仿真。非定常的数值模拟将有助于更好地理解下击暴流风的动力特征。数值结果表明，基于雷诺平均的Navier-Stokes方程进行的非定常数值模拟结果同根据实测数据提出的三种经验风剖面吻合良好，在目前实测资料稀少的情况下，有助于更好地研究下击暴流风的基本特征。

英文摘要：

As a kind of high intensity winds, the downburst usually comes forth during thunderstorm and has caused numerous structural failures around the world. The research confirmed that the wind field characteristics of downburst are quite different from boundary layer winds. Based on the widely available computational fluid dynamics （CFD） commercial code FLUENT, numerical simulations have been accomplished in the 1：2 000 geometry scale. The unsteady numerical simulation is helpful to understand the dynamics of downburst wind. The results achieved by the unsteady simulation on the basis of Reynolds averaged Navier-Stokes are fitted to the experiential wind profile well . The results indicate that the numerical simulation based on CFD provides a new solution to study the downburst wind characteristics under the current conditions without detailed full scale data.