Effect of Forced Transition on an Airfoil in Plunging Motion

Extensive experimental tests are conducted to examine the roughness effects on the aerodynamic performance of a modeling in an oscillatory motion. Forced transition is made by using a roubghness trip to have a real condition for simulation purposes. All tests are carried out in 0.45 0.45m low-speed wind tunnel. The model has 0.45m chord. Data were taken at a Reynolds number of 1.8*105 and at a range of reduced frequencies, k=0.047, 0.094 and 0. 141. Tests are conducted at plunging amplitudes of and at mean angle of attack of 0.5. The results indicate that the width of the hysteresis loop and position of the figure eight shape are influenced by the surface roughness significantly