Helical-groove and circular-trip effects on side force

When a slender body, such as a missile, is pitched at high angle of attack to an oncoming flow, it may experience a large side force due to the asymme tric shedding of the tip vortices. The side force is well known to be highl y detrimental to the performance of the Eight vehicle. We assess the effect iveness of two control devices, namely, the circular trips and the helical grooves, in alleviating the side force on a tangent ogive nose cylinder Sim ultaneous side force and pressure measurements taken in a wind tunnel show that the circular trip is generally more effective in reducing the side for ce than the helical grooves over a wide range of angle of attack, Detailed findings of their performances are reported.