At present, wind tunnel experiments afford the best means to investigate the aerodynamic characteristics of train/vehicles under cross winds. However, tests were performed in the past in a uniform flow which differs from actual flows in aerodynamic conditions. Since natural winds are turbulent with a boundary layer existing near the ground surface, it is necessary in wind tunnel tests to adopt wind conditions close to these in actuality. This paper briefly describes the test results of generating a boundary layer flow using spires and roughness elements of the Maibara wind tunnel and characteristics of the boundary layer flow.

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