Page Menu
Home
c4science
Search
Configure Global Search
Log In
Files
F86051470
pair_sph_idealgas.cpp
No One
Temporary
Actions
Download File
Edit File
Delete File
View Transforms
Subscribe
Mute Notifications
Award Token
Subscribers
None
File Metadata
Details
File Info
Storage
Attached
Created
Thu, Oct 3, 23:06
Size
7 KB
Mime Type
text/x-c
Expires
Sat, Oct 5, 23:06 (2 d)
Engine
blob
Format
Raw Data
Handle
21334014
Attached To
rLAMMPS lammps
pair_sph_idealgas.cpp
View Options
/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
http://lammps.sandia.gov, Sandia National Laboratories
Steve Plimpton, sjplimp@sandia.gov
Copyright (2003) Sandia Corporation. Under the terms of Contract
DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
certain rights in this software. This software is distributed under
the GNU General Public License.
See the README file in the top-level LAMMPS directory.
------------------------------------------------------------------------- */
#include <math.h>
#include <stdlib.h>
#include "pair_sph_idealgas.h"
#include "atom.h"
#include "force.h"
#include "comm.h"
#include "neigh_list.h"
#include "memory.h"
#include "error.h"
#include "domain.h"
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
PairSPHIdealGas::PairSPHIdealGas(LAMMPS *lmp) : Pair(lmp)
{
restartinfo = 0;
}
/* ---------------------------------------------------------------------- */
PairSPHIdealGas::~PairSPHIdealGas() {
if (allocated) {
memory->destroy(setflag);
memory->destroy(cutsq);
memory->destroy(cut);
memory->destroy(viscosity);
}
}
/* ---------------------------------------------------------------------- */
void PairSPHIdealGas::compute(int eflag, int vflag) {
int i, j, ii, jj, inum, jnum, itype, jtype;
double xtmp, ytmp, ztmp, delx, dely, delz, fpair;
int *ilist, *jlist, *numneigh, **firstneigh;
double vxtmp, vytmp, vztmp, imass, jmass, fi, fj, fvisc, h, ih, ihsq;
double rsq, wfd, delVdotDelR, mu, deltaE, ci, cj;
if (eflag || vflag)
ev_setup(eflag, vflag);
else
evflag = vflag_fdotr = 0;
double **v = atom->vest;
double **x = atom->x;
double **f = atom->f;
double *rho = atom->rho;
double *mass = atom->mass;
double *de = atom->de;
double *e = atom->e;
double *drho = atom->drho;
int *type = atom->type;
int nlocal = atom->nlocal;
int newton_pair = force->newton_pair;
inum = list->inum;
ilist = list->ilist;
numneigh = list->numneigh;
firstneigh = list->firstneigh;
// loop over neighbors of my atoms
for (ii = 0; ii < inum; ii++) {
i = ilist[ii];
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
vxtmp = v[i][0];
vytmp = v[i][1];
vztmp = v[i][2];
itype = type[i];
jlist = firstneigh[i];
jnum = numneigh[i];
imass = mass[itype];
fi = 0.4 * e[i] / imass / rho[i]; // ideal gas EOS; this expression is fi = pressure / rho^2
ci = sqrt(0.4*e[i]/imass); // speed of sound with heat capacity ratio gamma=1.4
for (jj = 0; jj < jnum; jj++) {
j = jlist[jj];
j &= NEIGHMASK;
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
rsq = delx * delx + dely * dely + delz * delz;
jtype = type[j];
jmass = mass[jtype];
if (rsq < cutsq[itype][jtype]) {
h = cut[itype][jtype];
ih = 1. / h;
ihsq = ih * ih;
wfd = h - sqrt(rsq);
if (domain->dimension == 3) {
// Lucy Kernel, 3d
// Note that wfd, the derivative of the weight function with respect to r,
// is lacking a factor of r.
// The missing factor of r is recovered by
// (1) using delV . delX instead of delV . (delX/r) and
// (2) using f[i][0] += delx * fpair instead of f[i][0] += (delx/r) * fpair
wfd = -25.066903536973515383e0 * wfd * wfd * ihsq * ihsq * ihsq * ih;
} else {
// Lucy Kernel, 2d
wfd = -19.098593171027440292e0 * wfd * wfd * ihsq * ihsq * ihsq;
}
fj = 0.4 * e[j] / jmass / rho[j];
// dot product of velocity delta and distance vector
delVdotDelR = delx * (vxtmp - v[j][0]) + dely * (vytmp - v[j][1])
+ delz * (vztmp - v[j][2]);
// artificial viscosity (Monaghan 1992)
if (delVdotDelR < 0.) {
cj = sqrt(0.4*e[j]/jmass);
mu = h * delVdotDelR / (rsq + 0.01 * h * h);
fvisc = -viscosity[itype][jtype] * (ci + cj) * mu / (rho[i] + rho[j]);
} else {
fvisc = 0.;
}
// total pair force & thermal energy increment
fpair = -imass * jmass * (fi + fj + fvisc) * wfd;
deltaE = -0.5 * fpair * delVdotDelR;
f[i][0] += delx * fpair;
f[i][1] += dely * fpair;
f[i][2] += delz * fpair;
// and change in density
drho[i] += jmass * delVdotDelR * wfd;
// change in thermal energy
de[i] += deltaE;
if (newton_pair || j < nlocal) {
f[j][0] -= delx * fpair;
f[j][1] -= dely * fpair;
f[j][2] -= delz * fpair;
de[j] += deltaE;
drho[j] += imass * delVdotDelR * wfd;
}
if (evflag)
ev_tally(i, j, nlocal, newton_pair, 0.0, 0.0, fpair, delx, dely, delz);
if (evflag)
ev_tally(i, j, nlocal, newton_pair, 0.0, 0.0, fpair, delx, dely,
delz);
}
}
}
if (vflag_fdotr) virial_fdotr_compute();
}
/* ----------------------------------------------------------------------
allocate all arrays
------------------------------------------------------------------------- */
void PairSPHIdealGas::allocate() {
allocated = 1;
int n = atom->ntypes;
memory->create(setflag, n + 1, n + 1, "pair:setflag");
for (int i = 1; i <= n; i++)
for (int j = i; j <= n; j++)
setflag[i][j] = 0;
memory->create(cutsq, n + 1, n + 1, "pair:cutsq");
memory->create(cut, n + 1, n + 1, "pair:cut");
memory->create(viscosity, n + 1, n + 1, "pair:viscosity");
}
/* ----------------------------------------------------------------------
global settings
------------------------------------------------------------------------- */
void PairSPHIdealGas::settings(int narg, char **arg) {
if (narg != 0)
error->all(FLERR,
"Illegal number of setting arguments for pair_style sph/idealgas");
}
/* ----------------------------------------------------------------------
set coeffs for one or more type pairs
------------------------------------------------------------------------- */
void PairSPHIdealGas::coeff(int narg, char **arg) {
if (narg != 4)
error->all(FLERR,"Incorrect number of args for pair_style sph/idealgas coefficients");
if (!allocated)
allocate();
int ilo, ihi, jlo, jhi;
force->bounds(arg[0], atom->ntypes, ilo, ihi);
force->bounds(arg[1], atom->ntypes, jlo, jhi);
double viscosity_one = force->numeric(FLERR,arg[2]);
double cut_one = force->numeric(FLERR,arg[3]);
int count = 0;
for (int i = ilo; i <= ihi; i++) {
for (int j = MAX(jlo,i); j <= jhi; j++) {
viscosity[i][j] = viscosity_one;
//printf("setting cut[%d][%d] = %f\n", i, j, cut_one);
cut[i][j] = cut_one;
setflag[i][j] = 1;
count++;
}
}
if (count == 0)
error->all(FLERR,"Incorrect args for pair sph/idealgas coefficients");
}
/* ----------------------------------------------------------------------
init for one type pair i,j and corresponding j,i
------------------------------------------------------------------------- */
double PairSPHIdealGas::init_one(int i, int j) {
if (setflag[i][j] == 0) {
error->all(FLERR,"All pair sph/idealgas coeffs are not set");
}
cut[j][i] = cut[i][j];
return cut[i][j];
}
/* ---------------------------------------------------------------------- */
double PairSPHIdealGas::single(int i, int j, int itype, int jtype,
double rsq, double factor_coul, double factor_lj, double &fforce) {
fforce = 0.0;
return 0.0;
}
Event Timeline
Log In to Comment