COMPARISON AND PARAMETRIC ANALYSIS OF WIND PROFILE CHARACTERISTICS OF IMPINGING JET AND WALL JET

Impinging jet and wall jet are used respectively as a wind field model, and numerical simulation is performed by adopting the RNG k-ε turbulence model based on Reynolds-Averaged Navier-Stokes (RANS) to obtain a steady wind field. Based on the numerical simulation with varying parameters, such as inflow diameter (D_jet) , the ratio of inflow height and diameter (H/D_jet)and inflow velocity (V_jet) in impinging jet, inflow height and inflow velocity (V_jet) in wall jet, different downburst wind profiles are obtained with different parameters, and the effects of these initial parameters on downburst wind profile characteristics were analyzed. The wind profile comparison of the wall jet and the impinging jet indicates that the horizontal component of its wind speed fits well in each radial position. Main features of the wind profile of horizontal component of both impinging jet and wall jet are obtained, while there are larger differences in the vertical component of the wind speed. Overall, when only considering the horizontal component of the wind speed, wall jet can be used as the model of a downburst in structural wind engineering field. By treating the outflow separately from the impinging jet through the wall jet model, the outflow region of the downburst can be simulated at a large-scale experiment in boundary layer wind tunnel.