Akademik Veri Yönetim Sistemi
39th Aerospace Sciences Meeting and Exhibit 2001, Reno, NV, Amerika Birleşik Devletleri, 8 - 11 Ocak 2001, (Tam Metin Bildiri)
A method of separation-control using alternating tangential blowing/suction with small speeds at multiple slots was proposed and the properties of this method were studied computationally by applying it to the flow-control of a thick airfoil. Using alternating 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 1.5U∞ for the blowing/suction, the separation is suppressed. Since the suction is more effective than the blowing in controlling separation, when the frequency of the blowing/suction is low, the global flow field varies with time periodically and the aerodynamic forces oscillate with large amplitude. When the frequency is relatively high (above 1) and with the speed of blowing/suction large enough for suppressing the separation, the global flow field does not vary with time. But the flow in the neighborhood of the slots (inside the boundary-layer) varies with time and the aerodynamic forces oscillate with small amplitude. © 2001 The American Institute of Aeronautics and Astronautics Inc. All rights reserved.