山体遮挡对滇池风生流的影响初探

用二维风生流数值模型模拟滇池湖流运动。滇池在主导风向西南风作用下，假定湖面风场是均匀的，数值模拟的湖流流态与实测湖流结果相差很大。而考虑山体遮挡影响，根据实测湖流期间现有的风情资料，在湖面上构造一非均匀风场，数值模拟结果与实测值基本一致。山体遮挡对滇池风生流的影响是不容忽视的。建议进一步进行湖流和湖面风向、风速监测，并建立过山气流数学模型，深入研究山体遮挡对湖泊风生流的影响。

Preliminary study on the effect of mountain sheltering on the wind-driven water current in Dianchi Lake

The currents in Dianchi lake were simulated by a two-dimension numerical model on wind-driven current. Numerical simulated flow field with uniform wind field and measured flows were not in agreement. Analysis of the measured winds data of the six stations around the shore of lake show that the wind directions in the six stations were not inconsistent, but the wind velocities in the zone sheltered by mountains along the west shore are 20% -50% lower than in the east shore of open water. It is evident that the wind field over lake is non-uniform due to the effect of mountain sheltering and needs to modify the wind input data in the model. According to the wind data measured, in the case of west-south wind over lake, the non-uniform wind field was artificially constructed by reducing wind velocities over lake in the zone sheltered by mountain. Using this non-uniform wind field, numerical simulated flow field was fitting better the measured flows. By comparing the mumerical simulated results between using uniform wind field and non-uniform wind field, it is obvious that the effect of mountain sheltering on the water currents in Dianchi Lake can not be ignored. In the case of west-south wind over lake, the general flow pattern in Dianchi Lake is a large anticlockwise circulation, the water velocities are low about several centimetres per second.