ABSTRACT
A computational study has been carried out to investigate the air flow over a
projectile provided with a triangular base at transonic and supersonic speeds. The
study aims to discuss the effect of the triangular base on the air flow characteristics
comparing with the flow over a typical projectile. One of the study main concerns is
the drag since it is the key issue in the projectile range. Good agreement is noted
when comparing the computational drag coefficients with the experimental work of
Platou [11]. The study shows that the flat surfaces of the unconventional boattail
cause the formation of a single normal shock wave at transonic speeds. Moreover,
these surfaces may be a main reason for the shock wave smearing at
transonic/supersonic speeds and lower turbulence level in the base region. A
diminishing of the wake behind the unconventional base is noted resulting in nearer
rear stagnation point and lower base drag.