| Circulation Control technology is a very effective way of achieving very high lift coefficients needed by aircraft during take-off and landing. Compared to a conventional high-lift system, a Circulation Control Wing can generate the same high lift during take-off/landing with fewer or no moving parts and much less complexity.; In this work, an unsteady three-dimensional Navier-Stokes analysis procedure has been developed and applied to CCW configurations. Steady jets, pulsed jets, the leading edge and trailing edge blowing can all be studied with this solver.; The effects of 2-D steady jets and 2-D pulsed jets on the aerodynamic performance of CCW airfoils have been investigated. It is found that a steady jet can generate very high lift at zero angle of attack without stall, and that a small amount of blowing can eliminate the vortex shedding, a potential noise source. It is also found that the pulsed jet can achieve the same high lift as the steady jet but at less mass flow rates, especially at a high frequency, and that the Strouhal number has a more dominant effect on the pulsed jet performance than just the frequency.; Three-dimensional simulations have also been done for two cases. The first is a streamwise tangential blowing on a wing-flap configuration. It is demonstrated that a gradually varied CC blowing can totally eliminate the flap-edge vortex, thus reducing the flap-edge noise. The second case involves spanwise tangential blowing over a rectangular wing with a rounded wing tip. It is found that CC blowing can not totally cancel or eliminate the tip vortex. However, it can control and modify the location of the tip vortex, and increase the vertical clearance between the wing and the tip vortex, thus reducing the blade vortex interaction and the BVI noise. |
