ABSTRACT
The present paper investigates the effect of streamwise slots applied to the boattail
section of a projectile at supersonic speeds. Experimental work was performed to show
the effect of the slots on the drag at Mach numbers M=1.36, 1.65 and 1.83. A single
configuration of the slot pattern was used with two different slot widths (0.5mm and
2.0mm). The physics of the cavity flow was computationally investigated as well as the
effect of the slots on the overall aerodynamic drag. Unlike the case of streamwise slots
at transonic speeds, the suction and blowing mechanism is absent at supersonic
speeds. It was found that there is a significant base drag reduction due to the presence
of the streamwise slots. The reduction in total drag is modest when the width is
W=0.5mm. However, the experiments showed that the drag increases at Mach
numbers ranging from 1.36 to 1.83 for a slot width W=2.0mm.