Effect of synthetic jets physical parameters on flow separation control over airfoil

The effect of synthetic jets on controlling flow separation over a NACA0015 airfoil was numerically analyzed using computational fluid dynamic (CFD) method. The synthetic jets were located at 12%c, 30%c and 70%c, respectively, from the leading edge (c is the chord length of the airfoil). The trends of flow separation control effect at these locations with the variation of angle of attack (AOA) and jet angle were analyzed. Meanwhile, the locations, phase angle and momentum coefficient of multi-location synthetic jets were analyzed. The two-dimensional unsteady incompressible Navier-Stokes equations were used to simulate unsteady separated flows. SST turbulence model was utilized for the computation, and the pressure-implicit with splitting of operators (PISO) algorithm was utilized for pressure correction. An implicit numerical treatment was adopted for time integral and the second order upwind scheme for space discretization. The numerical results show that: 1) when synthetic jets are located at 12%c, 30%c and 70%c from the leading edge, the tangential jet shows better control effect than normal jet; 2) for single and multi-location synthetic jets, the jet locations should be close to the separation point or prior to the separation point, only in this occasion can the purpose of flow control be achieved, and the closer the jet locations to the separation point, the better control effect can be expected; 3) the performance of multi-location synthetic jets can be improved by changing phase angle of multi-location synthetic jets.