Abstract: Based on a horizontal axis wind turbine of 33 kW, the wake flow field of thewind turbine under condition of uniform flow or turbulent flow of different intensities is simulated by using the method of large eddy current to simulate coupled actuator line, and the effect of turbulence on the wake and torque characteristics of horizontal axis wind turbine is also investigated. Simulated results indicate that: the energy exchange between the wake and the surrounding flow field of the wind turbine in the turbulent flow is stronger than that in the uniform flow. The turbulent velocity is faster therefore, so that velocity recovery in the wake area becomes faster as a result. The greater the turbulence is, the faster the velocity recovery may be. Compared with the uniform flow, the maximum loss rate of the wake velocity of the wind turbine decreases during turbulent flowing, but the degree of turbulence has less effect on the maximum loss rate of the wake velocity. The expanding rate of wake radius decreases gradually in the range from the plane of the wind turbine to twice the diameter of the wind turbine, and remains basically unchanged after twice the diameter. Turbulence will increase expansion of the wake, and the greater the turbulence is, the stronger the expansion will be. Under the condition of 11 m/s wind speed, the increase of turbulence leads to not only the decrease of mean value of the wind turbine torque, and the increase of fluctuation amplitude, but also the increase of energy consumption of the wind turbine torque in high frequency and low frequency ranges. The increase of energy consumption in the range of low frequency is faster.

Key words: wind turbine wake, turbulence intensity, wake radius, wind turbine torque