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Fixing errors in add heat

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This commit is contained in:
jtclemm
2024-08-09 15:32:52 -06:00
parent 07ac930733
commit a7c6b0ee42
2 changed files with 13 additions and 14 deletions
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17
doc/src/fix_add_heat.rst
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@ -18,11 +18,11 @@ Syntax
*constant* args = *rate*
*rate* = rate of heat flow (energy/time units)
*linear* args = :math:`T_{target}` *k*
:math:`T_{target}` = target temperature (temperature units)
*linear* args = *Ttarget* *k*
*Ttarget* = target temperature (temperature units)
*k* = prefactor (energy/(time*temperature) units)
*quartic* args = :math:`T_{target}` *k*
:math:`T_{target}` = target temperature (temperature units)
*quartic* args = *Ttarget* *k*
*Ttarget* = target temperature (temperature units)
*k* = prefactor (energy/(time*temperature^4) units)
* zero or more keyword/value pairs may be appended to args
@ -45,9 +45,9 @@ Examples
Description
"""""""""""
This fix adds heat to particles with the temperature attribute every timestep.
Note that this is an internal temperature of a particle intended for use with
non-atomistic models like the discrete element method.
This fix adds heat to particles with the temperature attribute every timestep
at a given rate. Note that this is an internal temperature of a particle intended
for use with non-atomistic models like the discrete element method.
For the *constant* style, heat is added at the specified rate. For the *linear* style,
heat is added at a rate of :math:`k (T_{target} - T)` where :math:`k` is the
@ -96,7 +96,8 @@ only enabled if LAMMPS was built with that package.
See the :doc:`Build package <Build_package>` page for more info.
This fix requires that atoms store temperature and heat flow
as defined by the :doc:`fix property/atom <fix_property_atom>` command.
as defined by the :doc:`fix property/atom <fix_property_atom>` command or
included in certain atom styles, such as atom_style rheo/thermal.
Related commands
""""""""""""""""

10
src/GRANULAR/fix_add_heat.cpp
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@ -21,7 +21,6 @@
#include "error.h"
#include "input.h"
#include "memory.h"
#include "update.h"
#include "variable.h"
using namespace LAMMPS_NS;
@ -125,7 +124,6 @@ void FixAddHeat::post_force(int /*vflag*/)
int *mask = atom->mask;
double *heatflow = atom->heatflow;
double *temperature = atom->temperature;
double dtinv = 1.0 / update->dt;
if (vstyle == ATOM) {
if (atom->nmax > maxatom) {
@ -142,7 +140,7 @@ void FixAddHeat::post_force(int /*vflag*/)
if (mask[i] & groupbit)
heatflow[i] = 0.0;
double vtmp, dt;
double vtmp;
if (vstyle == CONSTANT) vtmp = value;
if (vstyle == EQUAL) vtmp = input->variable->compute_equal(var);
for (int i = 0; i < atom->nlocal; i++) {
@ -150,11 +148,11 @@ void FixAddHeat::post_force(int /*vflag*/)
if (vstyle == ATOM) vtmp = vatom[i];
if (style == ADD) {
heatflow[i] += dtinv * vtmp;
heatflow[i] += vtmp;
} else if (style == LINEAR) {
heatflow[i] += dtinv * prefactor * (vtmp - temperature[i]);
heatflow[i] += prefactor * (vtmp - temperature[i]);
} else if (style == QUARTIC) {
heatflow[i] += dtinv * prefactor * (pow(vtmp, 4.0) - pow(temperature[i], 4.0));
heatflow[i] += prefactor * (pow(vtmp, 4.0) - pow(temperature[i], 4.0));
}
}
}