Introduction  In order to analyze the influence of atmospheric stability on the output of wind turbines, and to provide technical reference for improving the simulation accuracy of CFD wind energy resources.

  Method  Based on the observation data of different heights of two wind towers in flat and complex mountainous terrain, including wind speed, air temperature, air pressure and other data of multi-layer height, the atmospheric stability of the two wind towers in the region was calculated by using the Moning-Obkhov length method, and the stability calculation results were classified according to Irwin atmospheric stability classification standard.

  Result  The results show that: in the near surface layer, the vertical mixing effect caused by the atmospheric thermal effect in complex mountain area is more obvious, and the atmospheric instability is stronger, but the vertical mixing effect is not sufficient; The impact of atmospheric stability on wind turbine output in complex mountainous area is greater than that in flat terrain, and its uncertainty is higher. The reason largely depends on the complexity of atmospheric stability, so it is more necessary to consider the impact of atmospheric stability in wind energy resource assessment.

  Conclusion  It is necessary to consider the influence of atmospheric stability in CFD wind farm fluid modeling, especially under the condition of ultra-low wind speed complex mountain site, the evaluation of atmospheric stability is particularly important for fan selection and power generation simulation accuracy.