不同地貌上风速风向逐秒变化的观测

风力在速度与方向上的不稳定性可引发结构的振动并可导致结构损坏。由于气象资料取值周期较长而结构自振周期一般在钞的数量级，因此现有描述风不稳定性的数据常不符合结构动力分析的需要。对滨海、高山及城郊等不同地貌测点其风速、风向同时逐秒的变化进行了观测和记录。数据分析显示，滨海测点风不稳定性较小，高山测点在不同风向下所测风皆有一定程度的不稳定性，而城郊测点风不稳定性较大，表明自然风在风速、风向方面的不稳定主要与地貌及地形条件有关。认为在不利地形条件下工作的结构应进行必要的风动力分析。

Observation of High Frequency Turbulence of Natural Wind on Condition of Different Landforms

The instability of wind in speed and direction could lead to vibration in the structure and cause its damage. Because the meteorological data to be take in the longer period but free-vibration period of the construction is order of magnitude in second, the present data to describe instability of wind does not meet the demand of the construction motive analyzing. The observation of simultaneous change of wind speed and direction by seconds at seaside, mountain and outskirts of a city shows that instability of wind is less in the seaside and is more in the outskirts and wind observed is some instability in different direction of wind in the mountain site. It indicates the unsteadiness of natural wind in the wind velocity and direction is mainly related with the landforms and relief. Therefore, the wind dynamical analysis is necessary for constructions working in the disadvantageous landform conditions.