基于改进的OBV模型的下击暴流风荷载模拟  

Numerical simulation of downburst wind loads based on modified OBV model

作　　者：瞿伟廉[1] 吉柏锋[1] 王锦文[1] 

机构地区：[1]武汉理工大学道路桥梁与结构工程湖北省重点实验室,湖北武汉430070

出　　处：《地震工程与工程振动》2009年第1期146-152,共7页Earthquake Engineering and Engineering Dynamics

摘　　要：下击暴流是雷暴天气产生的近地面短时强风,具有和大气边界层近地风显著不同的风场特征,其风荷载数值模拟方法也和常规风荷载模拟方法不同。在将下击暴流风速表达为时变的平均风速和调制的非平稳脉动风速之和的前提下,本文采用基于改进的OBV模型(Oseguera and Bowles/Vi-croy(OBV))的方法来模拟平均风速,其平均风速直接由改进的OBV模型表达,而不同于已往研究中将平均风速表达为竖向风剖面与时间函数的乘积,并采用结合快速傅里叶变化的谐波叠加法来模拟调制的非平稳脉动风速。改进的OBV模型考虑了下击暴流的风暴中心移动和强度演化的影响,更准确地描述了下击暴流的实际物理过程。通过实例仿真,说明结果准确合理。Downburst is an outburst strong wind on or near the ground, and its field characteristics are significantly different from boundary layer winds. The authors discuss a new numerical simulation method of the downburst wind loads on the basis of the previous research. Firstly, the wind speed is expressed as the sum of an instantaneous mean wind speed and an amplitude-modulating non-stationary fluctuating wind speed. Secondly, a new method based on the modified Osegguera and Bowles/Vicroy （OBV） model to simulate the mean wind is presented and the fluctuating wind is simulated by a modified spectral representation method. The new method contains the effect of the translational motion and the time-dependent decay of the storm. Full agreement is reached between data from the new method and full-scale data from a high intensity downburst that occurred at Andrews Air Force Base in 1983.

关 键 词：下击暴流 风荷载 风速时程 改进的OBV模型 谐波叠加法 

分 类 号：TU312.1[建筑科学—结构工程]