more comments:interaction.py
This commit adds more comments about how and why we project rod tangent
vector in friction plane, with previous commit.
@@ -179,7 +179,8 @@ class AnistropicFrictionalPlane(NoForces, InteractionPlane):
self.plane_normal.reshape(3, 1), plane_response_force_mag.shape[0], axis=1
)
# First compute component of rod tangent in plane. Because friction forces acts in plane not out of plane. Thus
- # axial direction has to be in plane, it cannot be out of plane.
+ # axial direction has to be in plane, it cannot be out of plane. We are projecting rod element tangent vector in
+ # to the plane. So friction forces can only be in plane forces and not out of plane.
tangent_along_normal_direction = np.einsum(
"ij, ij->j", system.tangents, normal_plane_collection
)
@@ -196,7 +197,6 @@ class AnistropicFrictionalPlane(NoForces, InteractionPlane):
tangent_perpendicular_to_normal_direction,
1 / tangent_perpendicular_to_normal_direction_mag,
)
- # axial_direction = system.tangents
element_velocity = 0.5 * (
system.velocity_collection[..., :-1] + system.velocity_collection[..., 1:]
)
