| The tremendous construction of high-rise buildings in China follows the social economic development and building technology improvement. In mountainous and hilly areas, the terrain produces speed-up effect in the wind field. And the slope, the height, the distance between hills and the angle of the inflow will affect the speed-up effect, complicating the wind field in different degree. However, the high-rise building is sensitive to wind load, due to the flexibility and low-frequency itself. In this paper, a combination of wind tunnel test and computational fluid dynamics analysis are adopted to study the value of wind load for structures, providing the appropriate parameters for the design value of wind load for the structural analysis of high-rise buildings in hilly terrain.Based on the previous research, the wind tunnel test is conducted in a boundary layer wind tunnel with two hill model with cosine shape. The further study of the detailed distribution of the speed-up effect contributes to obtain the wind profile and turbulence properties in windward side, lee side and lateral side of the hill body. In the numerical simulation analysis, the commercial computational fluid dynamics software ANSYS Fluent is employed. The effect of different factors like the height and slope of hill bodies, the distance between hills and the angle of inflow are studied. The results are in accordance with the ones from wind tunnel test.For a single hill body, the hill peak has the severest speed-up effect. The downwind part of the hill peak has obvious flow separation. The speed-up effect in the lateral side is not negligible. In the study, the comparison between the results obtained from wind tunnel test and the mainstream codes, the ASCE has the closest approximation to the wind tunnel test among Euro Code, Chinese GB and ASCE. For the windward side and lee side of the hill body, the speed-up effect start to grow from negative to the big positive peak value along the foot to the peak of hill body. And the velocity profiles appear to be the same in the region from the hill-waist to hill peak. In addition, the paper proposes the correction parameter to calculate the effects of the geometrical properties.For the topography with the oblique wind flow, the extent of influence varies with the change of inflow angle and distance between hills, but the extent of influence differs with the positions. The hill peak and the outside of the hill body have the least influence, while the inside has an obvious speed-up effect. In addition, advice for the site decision of buildings in hilly terrain is proposed. |
