+
+@article{ katsuragi13,
+ author = HKatsuragi #" and "# DJDouglas,
+ title = {Drag force scaling for penetration into granular media},
+ year = 2013,
+ month = may,
+ day = 29,
+ journal = PR:E,
+ volume = 87,
+ number = 5,
+ pages = {052208},
+ numpages = 5,
+ doi = {10.1103/PhysRevE.87.052208},
+ url = {http://link.aps.org/doi/10.1103/PhysRevE.87.052208},
+ publisher = APS,
+ abstract = {Impact dynamics is measured for spherical and
+ cylindrical projectiles of many different densities dropped onto
+ a variety non-cohesive granular media. The results are analyzed
+ in terms of the material-dependent scaling of the inertial and
+ frictional drag contributions to the total stopping force. The
+ inertial drag force scales similar to that in fluids, except
+ that it depends on the internal friction coefficient. The
+ frictional drag force scales as the square-root of the density
+ of granular medium and projectile, and hence cannot be explained
+ by the combination of granular hydrostatic pressure and Coulomb
+ friction law. The combined results provide an explanation for
+ the previously observed penetration depth scaling.},
+}