Numerical and Experimental Investigation of Slot-Blown Air Over a Cylinder

The paper investigates the concept of directional control of helicopters without tail rotor by means of the Coanda effect. Slot-blowing around a cylinder in a steady flow is modeled computationally, using the unsteady k-ω shear stress transport (SST) solver in NUMECA, as well as experimentally in the wind tunnel of the Université de Liège. While the concept, in general, is promising, it is shown that there are some potential problems, including pitch yaw coupling and some unsteady flow conditions. These problems exist under various circumstances and are due, at least, in part, to the complicated flow-field that governs this problem, even in two dimensions.