A three-dimensional hydrodynamic model is developed to study the propagation of dam-break-induced flood and the interaction between floods and buildings. In the proposed mathematical model, the volume of fluid (VOF) method and the immersed boundary (IB) method are used to address the air/water interface and fluid/structure interface, respectively. Barely a limited number of publications focus on 3D simulations of the dam-break flood impacting buildings in the long flume heretofore, for researching the dam-break flood impacting buildings involves some hard issues like wave breaking phenomena, flood–building interaction, and computational efficiency. Therefore, the highlights to this paper are as follows: (1) The THINC/SW (THINC with Slope Weighting), which is extremely simple and efficient and meanwhile can also solve the wave breaking process, is adopted in the paper. Furthermore, its numerical accuracy is comparable with the conventional VOF schemes that use geometrical reconstructions. (2) The direct forcing IB method, which can be easily applied to three-dimensional simulation, is adopted to promote the computational efficiency of the three-dimensional numerical model and handle flood–building interaction interface treatment. The proposed VOF/IB model is validated by the physical experiment results and is also compared with the two-dimensional depth-averaged Shallow-Water Equations, and Coupled Level Set/Volume of Fluid and Immersed Boundary models in terms of accuracy and efficiency.

建立了三维水动力模型，以研究溃坝引发的洪水的传播以及洪水与建筑物之间的相互作用。在提出的数学模型中，流体体积（VOF）方法和浸入边界（IB）方法分别用于解决空气/水界面和流体/结构界面。迄今为止，很少有出版物专注于对长堤上的溃坝洪水影响建筑物的3D模拟，因为研究溃坝洪水影响建筑物涉及一些棘手的问题，例如波浪破碎现象，洪水与建筑物的相互作用以及计算效率。因此，本文的重点如下：（1）THINC / SW（带有斜率加权的THINC）非常简单，高效，同时还可以解决波浪破碎的过程，在本文中采用。此外，其数值精度与使用几何重构的常规VOF方案相当。（2）采用直接强迫IB法，可以很容易地应用于三维模拟，以提高三维数值模型的计算效率，并处理洪水—建筑相互作用接口。通过物理实验结果验证了所提出的VOF / IB模型，并与二维深度平均浅水方程以及流体和沉浸边界耦合水平集/体积和沉浸边界模型进行了比较。可以轻松地将其应用于三维模拟，以提高三维数值模型的计算效率并处理洪水—建筑相互作用接口。通过物理实验结果验证了所提出的VOF / IB模型，并与二维深度平均浅水方程以及流体和沉浸边界耦合水平集/体积和沉浸边界模型进行了比较。可以轻松地将其应用于三维模拟，以提高三维数值模型的计算效率并处理洪水—建筑相互作用接口。通过物理实验结果验证了所提出的VOF / IB模型，并与二维深度平均浅水方程以及流体和沉浸边界耦合水平集/体积和沉浸边界模型进行了比较。