From 474bb7715443c438eacab46aa72ce679d6c555d1 Mon Sep 17 00:00:00 2001 From: sjplimp Date: Thu, 17 Jan 2013 18:00:52 +0000 Subject: [PATCH] git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@9287 f3b2605a-c512-4ea7-a41b-209d697bcdaa --- doc/fix_srd.html | 52 ++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 41 insertions(+), 11 deletions(-) diff --git a/doc/fix_srd.html b/doc/fix_srd.html index 8746be8e54..e34e6dd325 100644 --- a/doc/fix_srd.html +++ b/doc/fix_srd.html @@ -25,7 +25,7 @@ @@ -278,11 +287,31 @@ associated with the system, e.g. due to use of the f deform command to perform a simulation undergoing shear, then that is also accounted for. The mean velocity of each bin of SRD particles is set to the position-dependent streaming velocity, -based on the coordinates of the center of the SRD bin. Note that for -streaming simulations, if no thermostatting is performed (the -default), then it may take a long time for the SRD fluid to come to -equilibrium with a velocity profile that matches the simulation box -deformation. +based on the coordinates of the center of the SRD bin. Note that +collisions of SRD particles with big particles or walls has a +thermostatting effect on the colliding particles, so it may not be +necessary to thermostat the SRD particles on a bin by bin basis in +that case. Also note that for streaming simulations, if no +thermostatting is performed (the default), then it may take a long +time for the SRD fluid to come to equilibrium with a velocity profile +that matches the simulation box deformation. +

+

The rescale keyword enables rescaling of an SRD particle's velocity +if it would travel more than 4 mean-free paths in an SRD timestep. If +an SRD particle exceeds this velocity it is possible it will be lost +when migrating to other processors or that collisions with big +particles will be missed, either of which will generate errors. Thus +the safest mode is to run with rescaling enabled. However rescaling +removes kinetic energy from the system (the particle's velocity is +reduced). The latter will not typically be a problem if +thermostatting is enabled via the tstat keyword or if SRD collisions +with big particles or walls effectively thermostat the system. If you +wish to turn off rescaling (on is the default), e.g. for a pure SRD +system with no thermostatting so that the temperature does not decline +over time, the rescale keyword can be used. The no value turns +rescaling off during collisions and the per-bin velocity rotation +operation. The collide and rotate values turn it on for +one of the operations and off for the other.

@@ -326,8 +355,8 @@ the simulation, but treating them as intensive means they are not scaled when printed as part of thermodyanmic output.

These are the 12 quantities. All are values for the current timestep, -except the last three which are cummulative quantities since the -beginning of the run. +except for quantity 5 and the last three, each of which are +cummulative quantities since the beginning of the run.

No parameter of this fix can be used with the start/stop keywords of the run command. This fix is not invoked during energy @@ -360,7 +389,8 @@ for more info on packages.

The option defaults are lamda inferred from Tsrd, collision = noslip, overlap = no, inside = error, exact = yes, radius = 1.0, bounce = 0, -search = hgrid, cubic = error 0.01, shift = no, tstat = no. +search = hgrid, cubic = error 0.01, shift = no, tstat = no, and +rescale = yes.