Besides, the pitching moment Damping Factor was studied to determine the level of airfoil stall flutter stability. The formation of Laminar Separation Bubbles and suction peaks were also reported in low angles of attack. In the deep stall region the LEV spilled entirely and the flow was fully separated. In the attached flow region the LEV grew and shrunk over the upper surface but in the light stall region the LEV spilled on the airfoil while a small partial LEV remained at the leading edge. The results showed that LEV formed on the upper surface manifested different behavior. Three different regions were assumed to represent the pressure distribution over the airfoil. The motions were designed to maintain constant reduced frequency, Strouhal number and phase difference. The experiments were conducted in a closed-loop wind tunnel utilizing pressure transducers array. While the surface pressure distribution is of significant importance in stability and performance of an airfoil, not sufficient information is available on the pressure distribution in dynamic stall. This paper describes the experimental study of surface pressure over a supercritical airfoil which was oscillated in pure pitching, pure plunging and combined pitch-plunge motions at the Reynolds number of 8.76*105. Future extensions of the present work will be aimed at studying the differences in the outer-region energizing mechanisms due to APGs and increasing Reynolds number. This conclusion is supported by the larger wall-normal velocities and outer-scaled fluctuations observed in the lower-Rec cases.Thus, our results suggest that two complementing mechanisms contribute to the development of the outer region in TBLs and the formation of large-scale energetic structures: one mechanism associated with the increase in Reynolds number, and another one connected to the APG. This is reflected in the values of the inner-scaled edge velocity Ue+, the shape factor H, the components of the Reynolds-stress tensor in the outer region and the outer-region production of turbulent kinetic energy. Comparisons of the wing profiles with zero-pressure-gradient (ZPG) data at matched friction Reynolds numbers reveal that, for approximately the same beta distribution, the lower-Reynolds-number boundary layers are more sensitive to pressure-gradient effects. The results of four well-resolved large-eddy simulations (LESs) are used to characterize the effect of Reynolds number on APG TBLs subjected to approximately the same pressure-gradient distribution (defined by the Clauser pressure-gradient parameter beta). To this end, we analyze four cases at Reynolds numbers based on freestream velocity and chord length ranging from Rec = 100, 000 to 1,000,000, all of them with 5 degree angle of attack. Reynolds-number effects in the adverse-pressure-gradient (APG) turbulent boundary layer (TBL) developing on the suction side of a NACA4412 wing section are assessed in the present work.
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