Experimental Determination of the Drag Coefficient of Conical Penetrators and a Penetrator with a Flat Front End during Supersonic Motion in Sandy Soil

In this paper, we experimentally determine the drag coefficient when conical and cylindrical impactors penetrate into sandy soil. In the experiments, the half-opening angle of the conical tip of the penetrator (indenter) varied from 10° to 90°. The velocity of indenter movement varied in the range of 0.2–2.0 km/s. The average values of the drag coefficient are obtained for conical bodies during quasi-stationary supersonic motion in sandy soil with an average moisture content of 7–12% and for indenters with a flat front end in sandy soil with a moisture content of 0–16%. A significant dependence of the drag coefficient of thin cones (β < 25°) on the movement velocity and the absence of such a dependence (taking into account the experimental error) for obtuse cones and an indenter with a flat end were shown.