100 lines
5.1 KiB
Plaintext
100 lines
5.1 KiB
Plaintext
#===========================================================================#
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# Rigid sphere freely moving near a stationary plane wall in a system #
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# undergoing shear flow. #
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# Every 10 time steps the center of mass velocity and angular velocity of #
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# the sphere are printed to the screen. #
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# #
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# Here, gamma (used in the calculation of the particle-fluid interaction #
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# force) is calculated by default. Thus, the colloidal objects will have #
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# a slightly larger "hydrodynamic" radii than given by the placement of #
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# the particle nodes. #
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# #
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# Sample output from this run can be found in the file: #
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# 'wall_defaultgamma.out' #
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#===========================================================================#
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units micro
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dimension 3
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boundary p p f
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atom_style atomic
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#----------------------------------------------------------------------------
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# Need a neighbor bin size smaller than the lattice-Boltzmann grid spacing
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# to ensure that the particles belonging to a given processor remain inside
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# that processors lattice-Boltzmann grid.
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# The arguments for neigh_modify have been set to "delay 0 every 1", again
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# to ensure that the particles belonging to a given processor remain inside
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# that processors lattice-Boltzmann grid. However, these values can likely
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# be somewhat increased without issue. If a problem does arise (a particle
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# is outside of its processors LB grid) an error message is printed and
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# the simulation is terminated.
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#----------------------------------------------------------------------------
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neighbor 1.0 bin
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neigh_modify delay 0 every 1
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read_data data.one_radius16d2
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#----------------------------------------------------------------------------
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# None of the particles interact with one another.
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#----------------------------------------------------------------------------
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pair_style lj/cut 2.45
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pair_coeff * * 0.0 0.0 2.45
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neigh_modify exclude type 1 1
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mass * 100.0
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timestep 3.0
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group sphere1 id <> 1 320
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#----------------------------------------------------------------------------
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# Colloidal particle is initially stationary.
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#----------------------------------------------------------------------------
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velocity all set 0.0 0.0 0.0 units box
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#----------------------------------------------------------------------------
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# Create a lattice-Boltzmann fluid covering the simulation domain.
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# All of the particles in the simulation apply a force to the fluid.
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# (however, this fix does not explicitly apply a force back on to these
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# particles...this is accomplished through the use of the viscous_lb fix.
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# Use the standard LB integration scheme, a fluid density = 1.0,
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# fluid viscosity = 1.0, lattice spacing dx=4.0, and mass unit, dm=10.0.
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# Use the default method to calculate the interaction force between the
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# particles and the fluid. This calculation requires the surface area
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# of the composite object represented by each particle node. By default
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# this area is assumed equal to dx*dx; however, since this is not the case
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# here, it is input through the setArea keyword (i.e. particles of type 1
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# correspond to a surface area of 10.3059947).
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# Use the trilinear interpolation stencil to distribute the force from
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# a given particle onto the fluid mesh.
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# Create shear in the system, by giving the upper z-wall a velocity of 0.0001
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# along the y-direction, while keeping the lower z-wall stationary.
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#-----------------------------------------------------------------------------
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fix 1 all lb/fluid 1 1 1.0 1.0 setArea 1 10.3059947 dx 4.0 dm 10.0 trilinear zwall_velocity 0.0 0.0001
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#----------------------------------------------------------------------------
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# Apply the force due to the fluid onto the particles.
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#----------------------------------------------------------------------------
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fix 2 all lb/viscous
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#----------------------------------------------------------------------------
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# Integrate the motion of the particles, constraining them to move and
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# rotate together as a single rigid spherical object.
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#----------------------------------------------------------------------------
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fix 3 all rigid group 1 sphere1
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#----------------------------------------------------------------------------
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# Create variables for the center-of-mass and angular velocities, and output
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# these quantities to the screen.
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#----------------------------------------------------------------------------
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variable vx equal vcm(all,x)
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variable vy equal vcm(all,y)
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variable vz equal vcm(all,z)
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variable omegax equal omega(all,x)
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variable omegay equal omega(all,y)
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variable omegaz equal omega(all,z)
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thermo_style custom v_vx v_vy v_vz v_omegax v_omegay v_omegaz
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thermo 10
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run 200000
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