Research of mast shadow effect on the average wind speed and turbulence intensity by field experiment

Accurate measurement of the wind field is very important in wind engineering, the meteorological mast is the most common way for wind measurement, and the mast shadow effect is the main influence factor of the accuracy. The influence of the mast shadow effect on the average wind speed and turbulence intensity was studied by three meteorological mast at three different regions in China with one-year data, and the mast shadow effect was analyzed by Tower Distortion Factor (TDF) and Scatter Factor (SCF). The results show that meteorological mast has significant influence on the downstream air flow, and caused a wind speed reduction by 15.5% and a turbulence intensity raise by 26.1%; the mast blocking effect on the upstream air flow is weaker than the mast shadow effect, and the mast blocking effect caused a small wind speed reduction by 2.2% and a turbulence intensity raise by 0.4%. Further statistical results show that the mast shadow effect on the average wind speed and turbulence intensity is linearly negatively correlated with a correlation coefficient of −0.864, and a slope of −0.443. The mast shadow effect on Turbulence Intensity is more significant, and was 2.257 times of that on the average wind speed. On the average, the TDFs of the average wind speed and turbulence intensity were 0.0141−0.0314 and 0.0214−0.0385, respectively. The contribution of averaged wind speed and turbulence intensity were 34.6% and 49.0%, respectively. On the dispersion, SCFs of the average wind speed and turbulence intensity were 0.0179−0.0240 and 0.0648−0.0845, respectively, and the average contribution of the averaged wind speed and turbulence intensity were 10.5% and 10.8%. The mast shadow effect on the turbulence intensity was higher than the effect on the average wind speed, and the effect on the dispersion was close for both.