Abstract
Two-dimensional wing (NACA6409 airfoil) was installed in a water tunnel to visualize flow separations from the top urface of the MAV's wing at an attack of angle and three kinds of low Reynolds number. The angle of attack was 20 degrees, and Reynolds numbers were 0.85x10^4, 1.14x10^4 and 1.43x10^4, respectively. The flow separation from the wing top surface was visualized by PIV, and it was observed that separations grew big whenever Reynolds number became bigger.
