龙卷风风场特性的CFD数值模拟

CFD numerical simulation of tornado wind field characteristics

基于计算流体动力学方法建立了龙卷风发生装置的数值计算模型,对具有单涡结构的龙卷风风场特性进行了研究。分析了切向风速沿径向和高度的分布规律,并将切向速度沿径向的分布与Rankin涡模型和参数化气旋模型理论公式进行对比,验证龙卷风风场数值模拟结果的合理性。进一步研究了入口风速和入口角度改变对龙卷风风场特性的影响,并给出了各个数值计算模型近地面核心半径、最大切向风速和涡流比,进而可以获得不同尺度和不同强度的龙卷风风场。该方法为龙卷风风场模拟提供了新的研究途径,并可应用于建筑物的抗龙卷风设计研究。

Based on computational fluid dynamics （CFD）, a numerical model of tornado generator was es- tablished and the characteristics of tornado wind field with a single vortex structure were studied. Radial and altitudinal distributions of the tangential velocity were presented, and the comparison of the radial distribu- tion of tangential velocity with the theoretical formulas of Rankine vortex model and parameterized cyclone model was conducted, so as to verify the rationality of the numerical simulation results of tornado wind field. Influences on characteristics of tornado wind field were further studied by changing the inlet angle and veloci- ty magnitude. The parameters of each numerical calculation model were given, which include core radius, maximum tangential velocity and swirl ratio near surface. Therefore, the tornado-like wind field with differ- ent intensities and scales was obtained. The present method provides a new approach to simulate tornadoes and can be used for study on tornado-resistant building designs.