A COMPARATIVE STUDY ON THE SIMULATION OF NEUTRAL ATMOSPHERIC BOUNDARY LAYER BASED ON THE k-ε TURBULENCE MODEL

Accurately modeling the neutral equilibrium atmospheric boundary layers (ABL) is a fundamental problem in the field of computational wind engineering (CWE), which is a hot issue in recent years. This paper provides a comprehensive and systematical summary of the theoretical research advances on this topic in recent years from four aspects, that is, the inflow boundary conditions, the turbulence model parameters, the additional source and the wall function, respectively, and proposed a new set of model parameters and a general wall function based on the standard k-ε turbulence model. A numerical wind tunnel model was built to model a simple boundary layer flow by CFD (computational fluid dynamics) method according to the above four categories. Numerical results were compared and analyzed successively in details. It shows that the imposed inflow boundary conditions that were deduced from the analytical solution of the turbulent kinetic energy k equation do not necessarily generate the equilibrium ABL, which depends on the mathematical model of the k profile to a large extent. Apart from the inflow boundary conditions, the turbulence model parameters and the wall function also had a great effect on modelling the neutral equilibrium ABL. Adding source terms in the turbulence model equations cannot effectively improve the self-maintenance of the velocity and the turbulent kinetic energy profiles throughout the whole domain without any obstacles. The above conclusions would be helpful for the research on this topic.