Provided is a method of estimating a value of wind speed a wind turbine is subjected to, the wind turbine having a rotor with rotor blades at least one having an adaptable flow regulating device installed, the method including: obtaining values for power output of the wind turbine, rotor speed of the rotor, and pitch angle of the rotor blades; obtaining state information of the adaptable flow regulating device; and estimating the value of the wind speed based on the values for power output, rotor speed, pitch angle and the state information of the adaptable flow regulating device.