A study on boundary conditions of k-ε model in Computational Wind Engineering

Proceeded from the k-ε turbulence model control equation, two kinds of boundary conditions meet the theoretical conditions of horizontally homogenous Atmosphere Boundary Layer(ABL) were studied in detail, and their theoretical differences were compared. And then the class A wind field, which is suggested by the Chinese Wind-resistant Design Specification for Highway Bridges, was simulated as the inlet flow conditions in full scale using these two kinds of boundary conditions, with adapted k-ε model constants and wall conditions well defined. The results show that, in numerical simulation, both two kinds of boundary conditions, combined with adapted model constants and wall conditions, are able to construct horizontally homogenous ABL, which basically satisfy the conditions required by the code, but each has its own applicable scope. Based on these works, the relation between model constant C₁, turbulent dissipation rate ε and the numerical simulation results was studied, and a method to improve the results by modifying model constant and ε was introduced.