基于边界层风洞的下击暴流稳态风场特性数值模拟

Numerical Simulation on Steady Wind Field Characteristics of Downburst Based on Atmosphere Boundary Layer Wind Tunnel

针对下击暴流稳态风场模拟问题,基于计算流体动力学方法(Computational Fluid Dynamics,CFD),首先分别采用二维、三维冲击射流模型对下击暴流风场进行数值模拟,对下击暴流风场特性进行研究.在此基础上,根据下击暴流对桥梁结构作用主要受水平风速影响的特点,采用二维数值模拟方法对边界层风洞中设置倾斜平板模拟下击暴流水平风速风场进行了研究.最后,设计并加工了边界层风洞下击暴流水平风速模拟试验装置,在边界层风洞中进行了下击暴流水平风速风场模拟试验,并将数值模拟结果与试验结果和已有文献结果进行了比较.结果表明:下击暴流风场的二维冲击射流模型模拟结果与三维冲击射流模型模拟结果吻合较好,即二维冲击射流模型是一种有效的下击暴流风场简化模拟方法;在边界层风洞中设置倾斜平板所模拟的下击暴流水平风速风场数值模拟结果和风洞试验结果具有较好的一致性,并与冲击射流模型数值模拟结果和现场实测结果均吻合较好,即在边界层风洞中设置倾斜平板可模拟下击暴流水平风速稳态风场特性.

For the problems of downburst steady wind field simulation,based on Computational Fluid Dynamic(CFD)methods,firstly,2-dimensional(2-D)and 3-dimensional(3-D)impinging jet models were used to simulate the downburst wind field,and the characteristics of downburst wind field were studied.On this basis,according to the characteristics that the effect of downburst on bridge structures is mainly affected by the horizontal wind speed,the horizontal wind field of downburst in Boundary Layer Wind Tunnel(BLWT)with inclined plate was studied by using 2-D numerical simulation method.Finally,the horizontal wind filed simulation experimental device of the downburst in the BLWT was designed and manufactured,and the horizontal wind field simulation experiment of the downburst was carried out in the BLWT.The numerical simulation results were compared with the experimental results in this study and the results from the existing literature.The comparison results show that the simulation results of the 2-D impinging jet model for the downburst wind field are in good agreement with that of the 3-D impinging jet model,that is,the 2-D impinging jet model is an effective simplified simulation method for the downburst wind field.The numerical simulation results of the horizontal wind speed and wind field of the downburst simulated by setting up the inclined plate in the BLWT are in good agreement with the wind tunnel test results,and are in good agreement with the numerical simulation results of impinging jet model and the field measured results,that is,the characteristics of steady horizontal wind filed of downburst flow can be simulated by setting an inclined plate in BLWT.