  The Navier boundary condition for velocity slip on flat surfaces, when
expressed in tensor form, is readily extended to surfaces of any shape. We test
this assertion using molecular dynamics simulations of flow in channels with
flat and curved walls and for rotating cylinders and spheres, all for a wide
range of solid-liquid interaction strengths. We find that the slip length as
conventionally measured at a flat wall in Couette flow is the same as that for
all other cases with curved and rotating boundaries, provided the atomic
interactions are the same and boundary shape is properly taken into account.
These results support the idea that the slip length is a material property,
transferable between different flow configurations.
