git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@1728 f3b2605a-c512-4ea7-a41b-209d697bcdaa

This commit is contained in:
sjplimp 2008-04-09 17:29:51 +00:00
parent d77150a8b7
commit 1a589c7a39
6 changed files with 79 additions and 36 deletions

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@ -37,8 +37,8 @@ or <A HREF = "read_restart.html">read_restart</A> commands:
</P>
<UL><LI>R0 (distance)
<LI>K2 (energy/distance^2)
<LI>K3 (energy/distance^2)
<LI>K4 (energy/distance^2)
<LI>K3 (energy/distance^3)
<LI>K4 (energy/distance^4)
</UL>
<P><B>Restrictions:</B>
</P>

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@ -34,8 +34,8 @@ or "read_restart"_read_restart.html commands:
R0 (distance)
K2 (energy/distance^2)
K3 (energy/distance^2)
K4 (energy/distance^2) :ul
K3 (energy/distance^3)
K4 (energy/distance^4) :ul
[Restrictions:]

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@ -173,6 +173,8 @@ viscous</A>, <A HREF = "fix_nvt.html">fix nvt</A>
<P>The option defaults are axes = 1 1 1, scale = 1.0 for all types, no
region, and weight = 1.0.
</P>
<HR>
<A NAME = "Dunweg"></A>
<P><B>(Dunweg)</B> Dunweg and Paul, Int J of Modern Physics C, 2, 817-27 (1991).

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@ -164,5 +164,7 @@ viscous"_fix_viscous.html, "fix nvt"_fix_nvt.html
The option defaults are axes = 1 1 1, scale = 1.0 for all types, no
region, and weight = 1.0.
:line
:link(Dunweg)
[(Dunweg)] Dunweg and Paul, Int J of Modern Physics C, 2, 817-27 (1991).

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@ -24,7 +24,7 @@
<LI>args = list of arguments for a particular style
<PRE> <I>xplane</I> or <I>yplane</I> or <I>zplane</I> args = lo hi gamma xmu
lo, hi = position of lower and upper plane (either can be NULL)
lo,hi = position of lower and upper plane (distance units), either can be NULL)
gamman = damping coeff for normal direction collisions with wall
xmu = friction coeff for the wall
<I>zcylinder</I> args = radius gamma xmu
@ -34,11 +34,15 @@
</PRE>
<LI>zero or more keyword/value pairs may be appended to args
<PRE> keyword = <I>wiggle</I>
values = dim amplitude period
dim = <I>x</I> or <I>y</I> or <I>z</I>
amplitude = size of oscillation (distance units)
period = time of oscillation (time units)
<LI>keyword = <I>wiggle</I> or <I>shear</I>
<PRE> <I>wiggle</I> values = dim amplitude period
dim = <I>x</I> or <I>y</I> or <I>z</I>
amplitude = size of oscillation (distance units)
period = time of oscillation (time units)
<I>shear</I> values = dim vshear
dim = <I>x</I> or <I>y</I> or <I>z</I>
vshear = magnitude of shear velocity (velocity units)
</PRE>
</UL>
@ -62,20 +66,38 @@ axis is at x = y = 0.0, and the radius of the cylinder is specified.
For all wallstyles, a damping and friction coefficient for
particle-wall interactions are also specified.
</P>
<P>Optionally, a wall can be oscillated, similar to the oscillations of
frozen particles specified by the <A HREF = "fix_wiggle.html">fix_wiggle</A>
command. This is useful in packing simulations of granular particles.
If the keyword <I>wiggle</I> is appended to the argument list, then a
dimension for the motion, as well as it's <I>amplitude</I> and <I>period</I> is
specified. Each timestep, the position of the wall in the appropriate
<I>dim</I> is set according to this equation:
<P>Optionally, the wall can be moving, if the <I>wiggle</I> or <I>shear</I>
keywords are appended. Both keywords cannot be used together.
</P>
<P>For the <I>wiggle</I> keyword, the wall oscillates sinusoidally, similar to
the oscillations of frozen particles specified by the
<A HREF = "fix_wiggle.html">fix_wiggle</A> command. This is useful in packing
simulations of granular particles. The arguments to the <I>wiggle</I>
keyword specify a dimension for the motion, as well as it's
<I>amplitude</I> and <I>period</I>. Note that if the dimension is in the plane
of the wall, this is effectively a shearing motion. If the dimension
is perpendicular to the wall, it is more of a shaking motion. A
<I>zcylinder</I> wall can only be wiggled in the z dimension.
</P>
<P>Each timestep, the position of a wiggled wall in the appropriate <I>dim</I>
is set according to this equation:
</P>
<PRE>position = pos0 + A - A cos (omega * delta)
</PRE>
<P>where <I>pos0</I> is the position at the time the fix was specified, <I>A</I> is
the <I>amplitude</I>, <I>omega</I> is 2 PI / <I>period</I>, and <I>delta</I> is the
elapsed time since the fix was specified. The velocity of the wall is
also set to the derivative of this expression.
set to the derivative of this expression.
</P>
<P>For the <I>shear</I> keyword, the wall moves continuously in the specified
dimension with velocity <I>vshear</I>. The dimension must be tangential to
walls with a planar <I>wallstyle</I>, e.g. in the <I>y</I> or <I>z</I> directions for
an <I>xplane</I> wall. For <I>zcylinder</I> walls, a dimension of <I>z</I> means the
cylinder is moving in the z-direction along it's axis. A dimension of
<I>x</I> or <I>y</I> means the cylinder is spinning around the z-axis, either in
the clockwise direction for <I>vshear</I> > 0 or counter-clockwise for
<I>vshear</I> < 0. In this case, <I>vshear</I> is the tangential velocity of
the wall at whatever <I>radius</I> has been defined.
</P>
<P><B>Restart, fix_modify, output, run start/stop, minimize info:</B>
</P>
@ -102,8 +124,6 @@ LAMMPS</A> section for more info.
</P>
<P>Any dimension (xyz) that has a granular wall must be non-periodic.
</P>
<P>A zcylinder wall can only be oscillated in the z dimension.
</P>
<P><B>Related commands:</B>
</P>
<P><A HREF = "fix_wiggle.html">fix_wiggle</A>

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@ -17,7 +17,7 @@ wall/gran = style name of this fix command :l
style = {xplane} or {yplane} or {zplane} or {zcylinder} :l
args = list of arguments for a particular style :l
{xplane} or {yplane} or {zplane} args = lo hi gamma xmu
lo, hi = position of lower and upper plane (either can be NULL)
lo,hi = position of lower and upper plane (distance units), either can be NULL)
gamman = damping coeff for normal direction collisions with wall
xmu = friction coeff for the wall
{zcylinder} args = radius gamma xmu
@ -25,11 +25,14 @@ args = list of arguments for a particular style :l
gamman = damping coeff for normal direction collisions with wall
xmu = friction coeff for the wall :pre
zero or more keyword/value pairs may be appended to args :l
keyword = {wiggle}
values = dim amplitude period
dim = {x} or {y} or {z}
amplitude = size of oscillation (distance units)
period = time of oscillation (time units) :pre
keyword = {wiggle} or {shear} :l
{wiggle} values = dim amplitude period
dim = {x} or {y} or {z}
amplitude = size of oscillation (distance units)
period = time of oscillation (time units)
{shear} values = dim vshear
dim = {x} or {y} or {z}
vshear = magnitude of shear velocity (velocity units) :pre
:ule
[Examples:]
@ -52,20 +55,38 @@ axis is at x = y = 0.0, and the radius of the cylinder is specified.
For all wallstyles, a damping and friction coefficient for
particle-wall interactions are also specified.
Optionally, a wall can be oscillated, similar to the oscillations of
frozen particles specified by the "fix_wiggle"_fix_wiggle.html
command. This is useful in packing simulations of granular particles.
If the keyword {wiggle} is appended to the argument list, then a
dimension for the motion, as well as it's {amplitude} and {period} is
specified. Each timestep, the position of the wall in the appropriate
{dim} is set according to this equation:
Optionally, the wall can be moving, if the {wiggle} or {shear}
keywords are appended. Both keywords cannot be used together.
For the {wiggle} keyword, the wall oscillates sinusoidally, similar to
the oscillations of frozen particles specified by the
"fix_wiggle"_fix_wiggle.html command. This is useful in packing
simulations of granular particles. The arguments to the {wiggle}
keyword specify a dimension for the motion, as well as it's
{amplitude} and {period}. Note that if the dimension is in the plane
of the wall, this is effectively a shearing motion. If the dimension
is perpendicular to the wall, it is more of a shaking motion. A
{zcylinder} wall can only be wiggled in the z dimension.
Each timestep, the position of a wiggled wall in the appropriate {dim}
is set according to this equation:
position = pos0 + A - A cos (omega * delta) :pre
where {pos0} is the position at the time the fix was specified, {A} is
the {amplitude}, {omega} is 2 PI / {period}, and {delta} is the
elapsed time since the fix was specified. The velocity of the wall is
also set to the derivative of this expression.
set to the derivative of this expression.
For the {shear} keyword, the wall moves continuously in the specified
dimension with velocity {vshear}. The dimension must be tangential to
walls with a planar {wallstyle}, e.g. in the {y} or {z} directions for
an {xplane} wall. For {zcylinder} walls, a dimension of {z} means the
cylinder is moving in the z-direction along it's axis. A dimension of
{x} or {y} means the cylinder is spinning around the z-axis, either in
the clockwise direction for {vshear} > 0 or counter-clockwise for
{vshear} < 0. In this case, {vshear} is the tangential velocity of
the wall at whatever {radius} has been defined.
[Restart, fix_modify, output, run start/stop, minimize info:]
@ -92,8 +113,6 @@ LAMMPS"_Section_start.html#2_3 section for more info.
Any dimension (xyz) that has a granular wall must be non-periodic.
A zcylinder wall can only be oscillated in the z dimension.
[Related commands:]
"fix_wiggle"_fix_wiggle.html