Abstract: Experimental study on classical similarity functions and eddy viscosity in atmospheric turbulence flows in a wind farm of complex terrain were carried out. Measurements show that classical similarity functions are not appropriate in complex terrain while the eddy viscosity in the k-e turbulence model should be modeled either by calibrating C_m under near neutral conditions or by applying corrected function for non-neutral conditions. The corrected function is validated by measurements. The proposed similarity functions and the corrected modeling of eddy viscosity could benefit developing new k-e turbulence models for wind energy applications.