Study On Wind Characteristics Of The Engineering Site With Complex Terrain In Forest Area

In recent years,under the background of the rapid development of society,the engineering construction of urban dense areas has become increasingly saturated,and the suitability engineering construction of forest,grassland and other ecological areas is gradually emerging.For the suitability project of forestry ecological zone construction,structural wind resistance is the key to the design of the whole project.The reasonable determination of the basic wind speed,average wind profile and fluctuating wind characteristics of engineering structural design is not only the basis for structural designers to study the problem of wind-induced vibration of engineering structures,but also the key to structural wind-resistant design.Therefore,based on the means of field measurement and numerical simulation,this paper has carried out a series of research work for the purpose of studying the wind characteristics of engineering sites in forest areas with complex topography.,as follows.(1)A scheme for real-time observation of wind environment in forestry engineering sites in complex terrain was formulated,and the wind characteristics of forest areas in complex terrain under the influence of three distant typhoons were analysed and studied by selecting and analysing the on-site wind speed data during the typhoon influence.The study shows that:the average wind speed in the forest area under the influence of the three typhoons is larger,the turbulence intensity and gust factor decrease with the increase of the average wind speed,and the turbulence integration scale is influenced by the surface canopy;however,the average wind direction range of different typhoons varies greatly.(2)The mean wind and pulsating wind characteristics of forestry engineering sites in complex terrain were statistically analyzed based on field measurement data in autumn and winter.The results show that the mean wind speed profile is consistent with the trend of logarithmic rate,and the mean wind direction shows a deflection pattern with height;the probability density(PDF)distribution of turbulence intensity and gust factor at different heights follow logarithmic distribution;the pulsating wind power spectrum von Karman spectrum coincides.(3)A CFD numerical simulation method of the wind field in complex terrain based on GIS was established,a complete technical route of wind field simulation in complex terrain simulation and reasonable inlet boundary conditions were given,and a source term model was used to simulate the influence of surface trees on the wind field,and four working conditions were divided according to the incoming wind direction to simulate the wind environment in the Mao’er Mountain area.The study shows that the wind profile model in the specification is not fully applicable to the variation pattern of wind speed with height in forest areas with complex terrain.