平面壁面射流风场作用下建筑物表面风压数值模拟

采用平面壁面射流模拟下击暴流的出流段风场，通过协同流模拟下击暴流水平移动，基于计算流体动力学方法，采用雷诺应力模型（RSM）的Stress-Omega模型模拟了稳态下击暴流的平均风剖面，并在风场中建立高层建筑物模型，研究下击暴流风场中高层建筑物表面风压分布特性.结果表明，采用平面壁面射流模型得到的水平速度竖向风剖面与下击暴流理论风剖面以及试验结果吻合较好，壁面射流模型风场中建筑风压分布特征与冲击射流风洞试验一致；迎风面风压系数随着顺流向距离的增加而不断减小，随着射流入流湍流强度的增大而减小.当下击暴流风剖面半高值大于1.45倍建筑物高度时，壁面射流风场中建筑风压分布与大气边界层风场中类似.协同流对结构中下部风压分布影响较大，而风向角对最大风压的影响不大.
The downburst outflow wind field was modeled by plane wall jet, and the co-flow was used to simulate the translation of downburst. Based on the computational fluid dynamics（CFD） method，the velocity profile of steady downburst was simulated with Reynolds stress model（RSM），and then a high -rise building model was put into the wind field to study the surface pressure distribution. The velocity profile from the numerical analysis results matches well with the empirical models as well as the plane and radial wall jet experiments. The pressure distribution characteristics of the building model in plane wall jet flow is in good accordance with the results of the imping jet experiment. The pressure coefficient decreases when the downstream distance increases. The pressure coefficient decreases with the increase of wall jet inlet turbulence intensity. When the half-width of the downburst velocity profile is higher than 1.45 times height of the building, the pressure distribution in wall jet flow is similar with that in boundary layer. Co-flow mainly has influence on the structure in the lower part. The wind direction of wall jet has little effect on the maximum pressure.