Abstract
In this study,a visualization experiment was performed in order to confirm the flow pattern around airfoil with relative velocity fluctuation by In-line forced oscillating in the direction of flow.As a result,airfoil NACA0012 with attack angle of 5 degrees produce the separation in the stationary condition was observed by the experiments using dye streak method at Reynolds number Re=3.6×10^3.The investigation of the attack angle which does not separate in such low Reynolds number was performed,and it was confirmed that the separation occurs to 3 degrees.And airfoil with attack angle of 2 degrees which does not cause separation in stationary condition,was forced to oscillate with 2 kinds of relative velocity ratio(u_<max>/U=0.4,0.8).The flow separation on the surface of airfoil with attack angle which does not produce the separation in the stationary condition is produced even if the movement speed of airfoil is in the range which does not exceed main flow velocity.
