龙卷风近地移动梯度对低层房屋风场影响

Infuluence of Near-Ground Translational Gradient on the Tornado-Induced Wind-field Around a Low-rise Building

为研究龙卷风灾害机理,运用Burgers涡运动理论及平移风速梯度理论,建立了涡旋及平移运动合成下的准定常三维龙卷风模型,并进行了柱坐标下的Navier-stokes方程的数值求解,得到了速度场及压力场的表达式.由此,探讨了考虑近地平移风剖面分布下的风场规律及其对低层房屋的作用特点.研究表明:考虑平移风梯度后,龙卷风前端右侧涡核负压值增大,高度较小时负压增加更为明显.因此,对低层房屋所受风吸力的影响更大.

In order to research the mechanism of tornado＇s damage,this paper sets up the model of quasi-steady three-dimensional tornado formed in vortex and translational motion by using the theories of Burgers vortex and translational wind gradient,and make the calculation of the Navier-stokes equation under cylindrical coordinate,getting the expression of the velocity field and pressure field.Therefore,this paper discusses wind regulation under the consideration of distribution of near-Earth traoslational wind profile and its effects on lower-rise buildings.The study indicates that,after considering translational wind gradient,negative pressure in the right front of tornado core increased and the negative pressure increases more obviously when the height becomes lower.Therefore,the lower-rise buildings suffer greater impact of wind suction than higher ones.