Field Investigation And Wind Tunnel Simulation Of Strong Wind Characteristics In Coastal And Mountainous Regions

Aiming at strong wind in China Coastal and inland mountainous regions, mean and fluctuating wind characteristics have been investigated through field measurements and wind tunnel simulation. Parameterized models of strong wind characteristics and determination of design wind speed in mountainous region have been proposed, which are more applicable to structural wind resistant design in China. Meanwhile, impovement of wind simulation techniques has been studied in atmospheric boundary layer wind tunnels.From the view of wind engineering application, key concepts such as surface layer and neutral boundary layer have been illustrated. A " Strong Wind " principle is proposed, which is of great significance in wind engineering studies. The critical techniques and error factors concerning field measurement of wind characteristics are analysed; the essential meaning of basic wind speed and its relationship with altitude are evaluated. Mean wind characteristics are studied by selecting strong wind profile samples from collected meteorological observed database. Fluctuating wind speed data are collected in south-eastern coastal and inland mountainous regions of China with 3-d and 2-d ultrasonic anemometers. By using the strong wind speed samples, statistic wind parameters are analysed including turbulence intensity, gust factor, integral length scale of turbulence, power spectra of fluctuating speed and spatial coherence. In wind tunnel experiments, the present work has investigated mountainous topographic wind effects and passive/active wind simulation techniques of atmospheric boundary layer turbulence.The results of wind profile measurements indicate the power factor α is directional and smaller than that in the current code for the coastal terrain; the reference height should be large as possible for the sake of smallest error of wind speed determination on structure. With a power factor α larger than real value, the wind load estimation is to be conservative if choosing 10m as reference height. In mountainous region, the basic wind speed is proportional to altitude with a very small coefficient, which can be regressed by basic wind speeds from surrounded standard meteorological station. Regarding structures in the surface layer of mountainous region, the design wind speed is defined by regional basic wind speed multiplied by local topographic effective coefficients, which are mainly determined from model tests. For complex terrain in mountainous region, the power law of wind profile is inapplicable.The topographic effects on design wind speed in mountainous terrain are categorised into valley wind, over-hill wind and block-off wind. Because of the boundary layer effects due to side-slopes of the valley, the wind speed coefficient at the valley throat depends on altitude. It will increase with the altitude from less than 1.0 inside the valley up to over 1.0 at the height close to the mountain peaks on both sides. Over-hill wind will speed up at the top and slow down in the wake region. Block-off wind will significantly reduce the mean wind speed. Meanwhile, small protruding slopes will induce local speed-up and strong distrurbance.The filed measurement investigation of strong wind turbulence proves different characteristics of typoon, normal strong wind in flat coastal reagion and mountainous topographic...