Fig. 9: Initial increase of the velocity and orientation-dependence of the angular velocity.
From: Inertial self-propelled particles in anisotropic environments
a Normalized initial velocity \(\langle | \dot{{{{{{{{\bf{r}}}}}}}}}(t)| \rangle /\langle | \dot{{{{{{{{\bf{r}}}}}}}}}(0.5\,{{{{{{{\rm{s}}}}}}}})| \rangle\) of a particle starting from rest (solid curves) for initial orientations ϕ0 = 0 (cyan) and ϕ0 = π/2 (yellow). The difference between horizontal and vertical starting orientation is small and within the variation observed in simulations (dashed lines). This suggests that friction in the parallel and perpendicular direction is not significantly different. b Mean angular velocity \(\langle \dot{\phi }\rangle\) as a function of particle orientation ϕ (solid curves). The slight periodicity is an artifact of the initial conditions and can be reproduced by simulating with equal conditions (dashed curves). Both are shown for excitation amplitudes A = 1.28 g (upper row), A = 1.44 g (middle row), and A = 1.60 g (lower row).
