Separation control by alternating tangential blowing/suction at multiple slots

A method of separation-control using alternating tangential blowing/suction at small speeds on multiple slots was proposed and the properties of this method were studied by applying it to the flow-control of a thick airfoil. The method of numerically solving the Reynolds averaged Navier-Stokes equations was employed for the study. Using alternating tangential blowing/suction with small speeds, in the blowing phase, the boundary layer velocity profiles downstream of the slot are made fuller and more separation resistant and in the suction phase, the boundary-layer velocity profiles both up and downstream of the slot are made fuller and more separation resistant. For the airfoil considered in the paper (which is of 40 percent thickness and has ten slots), with a peak velocity of about 1.5 ∞