Abstract: Wind farm simulation is one of the most important processes in wind farm micro-siting.There exists a temperature difference between terrain surface and airflow due to multiple reasons such as sunlight and terrain infrared radiation.When temperature of terrain surface is higher than that of airflow，the temperature difference will cause natural convection and affect the flow near surface.The flow field difference between cases with consideration of this temperature difference and without is studied by running simulation on various terrain types and flow velocities.The simulation uses turbulence model based on standard k-ε model.The result shows that at lower flow velocity on plain terrain，the natural convection caused by temperature difference will affect the simulation result of flow field with a velocity fluctuation up to 10%.At larger flow velocity or on complex terrain，the natural convection still exists but is almost negligible.

Key words: wind farm simulation, terrain surface temperature, complex terrain

摘要： 风电场微观选址的一个重要方面是风场的计算。在实际情况中，由于日晒、地表辐射等原因，地表与空气之间存在温差。当地表温度高于空气温度时，温差引起的自然对流会影响地表附近的流动。基于k-ε湍流模型，对多个地形、不同风速、存在温差和不存在温差下的流场进行了模拟、对比，对不同情况下温差的影响进行了讨论。结果表明，在平坦地形、低风速情况下地表温度对流场影响较大，而在复杂地形、风速较高的情况下，地表温度影响较小甚至可忽略。

关键词: 风场模拟, 地表温度, 复杂地形