Effectiveness of passive devices for axisymmetric base drag13; reduction at mach 2

Experiments have been made to assessthe effectiveness of passive devices for reducing base and total afterbody drag at Mach 2. The devices examined ir.dude primarily base cavities and ventilated cavities. Results show that ventilated cavities offer significant base-drag reduction and net-drag reduction of engineering value. A correlation of base- and net-drag reduction for ventilated cavities has been suggested. Typical effects of these devices on boat-tailed and flared bases have also been assessed