The analytical and experimental study of the controlled spanwise-twisting maneuver.

We have experimentally and analytically investigated the effect of controlled spanwise twisting maneuver at Re 10000. We have performed the experiment for two Angle of attack. First AOA is 5 degree which is below the static stall angle and AOA=15 degree which is above the static stall angle. The results have shown an increase in lift and drag coefficient value as the twisting starts. The initial rise in the lift forces happens due to inertial forces. At angle of attack 5^o, there is no dip in the lift coefficient after the twisting whereas in case of AOA 15^o there is a delayed dip in the lift coefficient. The results of spanwise PIV experiments at 90%, 85% and 60% have shown the difference in Leading-Edge Vortex (LEV) development for straight and the twisting case. For the twisting case at 85 percent plane, we saw more separation in the flow near the leading edge. At the 60 percent span we have not seen a significant difference in vortex formation. We have developed an analytical model which is derived from Wagner’s theory and Lifting line theory. This model was able to predict lift with good accuracy for the small angle of attacks. For the larger angle of attacks (greater than 5^o), the discrepancies in the force value increases. Another model which we have developed can be implemented for higher AOA. In that model we have used leading edge suction parameter to LESP to model the leading edge vortex which forms when the value of the absolute LESP is higher than critical LESP.