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受复杂街区影响的城区洪水水流会呈现复杂的3维特征,从而导致基于浅水波方程的2维简化数值模型存在较大计算误差。该文利用无网Lagrange光滑粒子流体动力学(smoothed particle hydrodynamics,SPH)方法来构建城区洪水的计算模型。该计算模型呈现了较合理的3维水流特征,如水跃、水波涡旋、水流间断等。利用该模型分析探讨了3种结构不同的建筑底层对洪水演进的影响。结果表明:底层中空的建筑对洪水的阻力最小,大部分洪水水流会穿过中空底层;独立建筑实体底层地基对洪水水流阻力最大,同时受到的冲击力也最大,可以反射回大部分的水流。
Urban flood currents affected by complex blocks will present complex 3-D features, resulting in large computational errors in 2-D simplified numerical models based on shallow water equations. In this paper, a non-net Lagrange smoothed particle hydrodynamics (SPH) method is used to construct a computational model of urban flood. The calculation model presents a more reasonable three-dimensional flow characteristics, such as water jump, water vortex, water flow intermittent and so on. This model is used to analyze and discuss the influence of three kinds of architectural underlays on flood evolution. The results show that the building with hollow basement has the least resistance to flood and most of the flood water will flow through the hollow basement. The basement of independent building has the highest resistance to flood water flow and the largest impact force at the same time, which can reflect most of the water flow.