ConcentricCylinders

class hoomd.mpcd.geometry.ConcentricCylinders(inner_radius, outer_radius, angular_speed=0.0, no_slip=True)

Bases: Geometry

Concentric cylinders.

Parameters:

• inner_radius (float) – Radius of inner cylinder.

• outer_radius (float) – Radius of outer cylinder.

• angular_speed (float) – Angular speed of the outer cylinder in the counterclockwise direction.

• no_slip (bool) – If True, surfaces have no-slip boundary condition. Otherwise, they have the slip boundary condition.

ConcentricCylinders confines particles between two cylinders centered around the origin. The inner cylinder is stationary, but the outer cylinder can rotate counterclockwise about the z axis with constant angular_speed.

Examples:

Stationary concentric cylinders with no-slip boundary condition.

cylinders = hoomd.mpcd.geometry.ConcentricCylinders(
    inner_radius=2.0, outer_radius=5.0
)
stream = hoomd.mpcd.stream.BounceBack(period=1, geometry=cylinders)
simulation.operations.integrator.streaming_method = stream

Stationary concentric cylinders with slip boundary condition.

cylinders = hoomd.mpcd.geometry.ConcentricCylinders(
    inner_radius=2.0, outer_radius=5.0, no_slip=False
)
stream = hoomd.mpcd.stream.BounceBack(period=1, geometry=cylinders)
simulation.operations.integrator.streaming_method = stream

Moving outer cylinder.

cylinders = hoomd.mpcd.geometry.ConcentricCylinders(
    inner_radius=2.0,
    outer_radius=5.0,
    angular_speed=1.0,
    no_slip=True,
)
stream = hoomd.mpcd.stream.BounceBack(period=1, geometry=cylinders)
simulation.operations.integrator.streaming_method = stream

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Members inherited from Geometry:

no_slip

Plates have a no-slip boundary condition when True. Read more...

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Members defined in ConcentricCylinders:

inner_radius

Radius of inner cylinder (read only).

Type:

float

outer_radius

Radius of outer cylinder (read only).

Type:

float

angular_speed

Angular speed of outer cylinder (read only).

angular_speed will have no effect if no_slip is False because the slip surface cannot generate shear stress.

Type:

float