EXPERIMENTAL RESEARCH ON AMPLITUDE CHARACTERISTICS OF COMPLEX HILLY TERRAIN WIND FIELD

There is a great difference between the wind field characteristics in a complex hilly terrain and that in a single hill. In order to get the distribution of mean and fluctuating wind velocity in a complex hilly terrain, several wind tunnel tests with different interval distances, different slopes and heights have been done. The results indicate that, with the increasing of the interval distance, the mean velocity speed-up ratio at the hilltop reduces quickly and that at the leeward changes from positive to negative quickly. With the increasing of the slope, the mean velocity speed-up ratio at the hilltop increases and then finally keeps stable. There is a critical value of the slope. When the slope is less than the value, the speed-up ratio at the leeward is negative, otherwise it becomes positive. The root mean square speed-up ratio of the fluctuation wind velocity becomes the same as that under the condition of the single hill in the form of the linear model. When the slope of the distributed hill is lager than the obscure hill, the root mean square speed-up ratio mainly depends on the distributed hill, otherwise, it depends on the obscure hill. The effects of the height of the obscure hill are all insignificant. The revised models of the mean velocity and the fluctuation velocity root mean square are proposed according to the wind tunnel test results.