Experimental study of morphology scaling of a projectile obliquely impacting into loose granular media

Abstract

The morphology scaling of a spherical projectile obliquely impacting into loose granular media is experimentally investigated. The influences of projectile’s releasing distance, diameter and oblique impact angle are mainly considered. Based on the experimental results, four scaling laws are eventually proposed to describe the variations of the length, width, depth of impact crater and the penetration depth of projectile after impacting. We find that when the impact angle is larger than a critical value, these quantities all exhibit power law dependences on the releasing distance, diameter and impact angle of projectile, which are analogous to that obtained in other similar vertical impacting experiments. It is also observed that once the oblique impact angle exceeds this critical value, the tadpole-shaped impact crater may commonly evolve into an elliptical one. At small impact angles, we find that the scaling laws on both the width and the depth of impact crater are still valid, although the corresponding fitting exponents have slightly deviated from those values at larger impact angles. However, the length of crater and the penetration depth of projectile seem to no longer yield such proposed scaling laws, possibly due to the different physical mechanism induced by the rebounding movements of projectile at small impact angles.