Abstract: The unsteady k-ω turbulence model and the sliding grid technology are used to research on the aerodynamic characteristics of straight vertical axis wind turbine in two-dimensional numerical study. The wind turbine has three 3 m-diameter, 3 m-height and 0.44 m-length airfoil blades. Aerodynamic characteristics of a single blade and of the wind turbine and the pressure characteristics of blade surface in three different rotation speeds are researched. The results conclude that：With the rotation speed arising, the pressure difference of the blade two surface sides is increasing；The pressure side has a tiny increasing, the suction side has a much bigger increasing, and this proves the suction side has a bigger contribution to the increasing power. With the speed increasing, the maximum torque of blade in upstream half circle increases firstly and decreases later, and has an optimum rotation speed with a bigger maximum torque; while the torque of downstream half circle decreases even is a negative value; these prove the upstream circle is the main power production zone. The whole power is determined by the torques of the upstream half and of the downstream half circle and rotation speed, only the relationships are balanced then the rotor power could be promoted.

Key words: Lift-type wind rotor, Pressure characteristic, Rotation speed, Sliding grid