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从k-ε湍流模型控制方程入手,对两类满足平衡大气边界层理论要求的入口边界条件进行了详细分析,比较了二者的理论差异。然后以我国公路桥梁抗风规范中建议的A类风场为来流条件,定义了相应的k-ε模型常数与壁面条件,使用两类边界条件进行数值模拟。计算结果表明:两类边界条件结合相应的模型常数与壁面条件,均能在数值模拟中构建基本满足规范要求的平衡大气边界层,但各有其适用范围。在此基础上,对模型常数C1和湍动能耗散率与数值模拟结果之间的关系进行了研究,采用修改模型常数与边界条件的方法,改善了数值模拟结果。
Starting with the governing equations of k-ε turbulence model, two types of inlet boundary conditions that satisfy the equilibrium atmospheric boundary layer theory are analyzed in detail, and the theoretical differences between the two are compared. Then, according to the proposed A-type wind field in the wind-resistance codes of highway bridges in our country, the corresponding k-ε model constants and wall conditions are defined and two types of boundary conditions are used for numerical simulation. The calculation results show that both types of boundary conditions, combined with the corresponding model constants and wall conditions, can build a balanced atmospheric boundary layer that basically meets the specifications in numerical simulation, but each has its own applicable scope. On the basis of this, the relationship between the model constant C1 and the turbulent kinetic energy dissipation rate and the numerical simulation results is studied. The numerical simulation results are improved by modifying the model constants and the boundary conditions.