Rigid Bodies

RigidBodySystem(initial_condition;
               boundary_model=nothing,
               contact_model=nothing,
               acceleration=ntuple(_ -> 0.0, ndims(initial_condition)),
               particle_spacing=initial_condition.particle_spacing,
               max_manifolds=8,
               source_terms=nothing, adhesion_coefficient=0.0,
               color_value=0)

System for particles of a rigid structure.

The rigid body is represented by particles and advanced with rigid-body translation and rotation. Fluid-structure interaction forces are reduced to resultant force and torque and applied consistently to all rigid particles.

Arguments

• initial_condition: Initial condition representing the rigid particles.

Keywords

• boundary_model: Boundary model for fluid-structure interaction (see Boundary Models).
• contact_model: Optional rigid contact model. If specified, rigid-wall and rigid-rigid collisions are enabled.
• acceleration: Global acceleration vector applied to all rigid particles.
• particle_spacing: Reference particle spacing used for time-step estimation.
• max_manifolds: Maximum number of wall-contact manifolds cached per rigid particle.
• source_terms: Optional source terms of the form (coords, velocity, density, pressure, t) -> source.
• adhesion_coefficient: Wall-adhesion strength used by Akinci-type surface tension models when fluids interact with this rigid body. This is only evaluated for fluid-structure interaction with surface-tension-enabled fluid systems.
• color_value: Integer label stored as system.cache.color. Currently this is used with BoundaryModelDummyParticles during colorfield initialization so fluids using ColorfieldSurfaceNormal can detect contact with rigid bodies, it participates in the multi-system color sanity check for surface-tension setups, and it is written to VTK output as "color".

RigidContactModel(; normal_stiffness,
                  normal_damping=0.0,
                  contact_distance=0.0)

Basic rigid contact model stored on a rigid body. It is currently used for both rigid-wall and rigid-rigid contact. The contact force consists of a linear normal spring-dashpot contribution only. If contact_distance == 0, the particle spacing of the RigidBodySystem will be used as contact distance.