Abstract:

In early researches and the latest specifications of some developed countries,the exponential-law calculation models are often used to calculate the speedup effect of wind velocity at the tops of moderate hills and crests,and the parameters of different models are variable.In order to solve this problem,the influences of the slope and the height of a hill as well as the terrain conditions on the speedup effect are numerically simulated with the CFD software Fluent 6.2.According to the simulated results,a logarithmic-law calculation model of average speedup effect is proposed based on the fitting of all parameter values,which is available for steeper hills and crests.From the comparison of the proposed model and the previous model as well as the existing specifications,it is found that the proposed logarithmic-law model is more accurate than the exponential-law one in terms of the description of speedup effect of near-surface wind velocity in hilly terrain.

Key words: hilly terrain, speedup effect, hill height, hill slope, landform, numerical simulation, exponential law, logarithmic law