Dynamic Stall Control through Passive Devices in Hybrid Configuration

Abstract

Numerical simulation of different passive control devices in hybrid configurations have been done to control dynamic stall. Previous studies have been carried out by researchers on different passive devices in isolation(vortex generators, gurney flap, droop leading edge etc) and by extracting the positive effects of these passive devices, researchers further focused on introducing hybrid configurations (mostly droop leading edge and gurney flap) on the airfoil and optimized their physical parameters to achieve the best flow control. In the present research, parametric study was carried out and then a combination of these three passive control devices have been used with an intent to extract the positive effects of each of these for better flow control. 2D computational analysis on an oscillating NACA 0012 airfoil was carried under deep dynamic stall conditions. Computational analysis was carried out on different passive devices; vortex generators (VGs), Fixed Droop Leading Edge (FDLE) and gurney flap (GF), in Single Passive Device (SPD) configuration. Results indicated that the height and location of the vortex generator had a profound effect on dynamic stall phenomenon while the fixed droop showed excellent dynamic stall control. The gurney flap contributed in increasing the lift but at the expense of increased drag and moment coefficient. In the Triple Passive Device (TPD) configuration case VG (H=7.6mm at 10%c), which was somewhat successful in Single Passive Device (SPD) configuration, with FDLE of 20 O and GF 1%c failed to contribute towards successful flow control, however the results improved when the same VG was moved to 15%c and 40%c. Although VG (H=2.5mm at 0.5%c and 10%c) failed to alter the flow in Single Passive Device (SPD) configuration, it proved successful when used in hybrid combination with FDLE 20 O and GF 1%c.