fix_wiggle.html
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	<H3>fix wiggle command
	</H3>
	<P><B>Syntax:</B>
	</P>
	<P>fix ID group-ID wiggle dim amplitude period
	</P>
	<UL><LI>ID, group-ID are documented in <A HREF = "fix.html">fix</A> command
	<LI>wiggle = style name of this fix command
	<LI>dim = <I>x</I> or <I>y</I> or <I>z</I>
	<LI>amplitude = size of oscillation (distance units)
	<LI>period = time of oscillation (time units)
	</UL>
	<P><B>Examples:</B>
	</P>
	<PRE>fix 1 frozen wiggle 3.0 0.5
	</PRE>
	<P><B>Description:</B>
	</P>
	<P>Move a group of atoms in a sinusoidal oscillation. This is useful in
	granular simulations when boundary atoms are wiggled to induce packing
	of the dynamic atoms. The dimension <I>dim</I> of movement is specified as
	is the <I>amplitude</I> and <I>period</I> of the oscillations. Each timestep
	the <I>dim</I> coordinate of each atom is set to
	</P>
	<PRE>coord = coord0 + A - A cos (omega * delta)
	</PRE>
	<P>where <I>coord0</I> is the coordinate 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 atom is
	set to the derivative of this expression.
	</P>
	<P><B>Restrictions:</B> none
	</P>
	<P><B>Related commands:</B> none
	</P>
	<P><B>Default:</B> none
	</P>
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