An analysis of cross section of helicopter tail boom for NOTAR^TM system

Lift on circulation control circular cylinder is calculated via numerical simulations based on 2D realizable k-Epsilon viscous model and compared with experimental data. The simulation result shows acceptable agreement with test data. With the proved grid and simulation method, lift on series of three different types of cross sections with different geometry parameters(blow angles, referenced position of slot, referenced circular cylinder diameters, and number of slots) or testing parameters(jet flow velocities, down wash flow velocities) is simulated. The results show that lift on circulation control tail boom could be increased with same power consumption, the stability of the attached flow could be enhanced by optimizing the shape of the cross section of the tail boom and the position of the slot(s) relative to the large curvature zone of the cross section where the attached flow is supposed to separate from the surface. It is also revealed that larger down wash velocity or smaller blow angle helps increasing the effect of optimizing of the shape and relative position of the slot(s).