The objective of this study is to understand physical mechanism of the effects of corner modification on aerodynamic characteristics of a type of square cylinder. Especially, we focus on dependency on the following parameters : the shape of corners, the characteristics of approaching flows and dimension of the model. We carried out wind tunnel tests for the measurements of the aerodynamic forces, such as averaged and fluctuating components of lift and drag forces, which act on a 2D or a 3D square cylinder with chamfered or rounded corners in smooth or homogeneous turbulent flow. Also, in order to confirm the flow structures under above condition, 3D numerical simulations are performed for a 2D cylinder in smooth flow.
