Introduction

2D multiphase SPH/SDPD code (authors: Xiangyu Hu, Sergey Litvinov, Oliver Oberinger, Martin Bernreuther, Andreas Mattes).

Build

$ (cd src && make)
$ (cd example && make)

make test runs tests (requres atest).

Cases

Run fluctuating liquid, Couette flow, and elliptic drop: cases/thermal.cfg, cases/couette.cfg, cases/ellipse.cfg.

Configuration file

To use the initial condition file

INITIAL_CONDITION <1/0>

The level of statistics output

DIAGNOSE 2

number of cells in x and y direction

CELLS <nx> <ny>

size of one cell

 CELL_SIZE 5.0e-3

support length

 SMOOTHING_LENGTH 5.0e-3

the number of particle in one direction in a cell

 CELL_RATIO	3

the basic of units (used for dimensionless calculations)

 DIMENSION <length> <velcoity> <density> <temperature>

simulation time

 TIMING <inital time> <the last time> <output time interval>

gravity force vector

 GRAVITY <gx> <gy>

Boundary conditions (order is as follow X0, X1, Y0, Y1) type code 1: periodic 0: wall

BOUNDARY
<type codes of boundary <velocity of the wall>
...

NUMBER_OF_MATERIALS <numb_mat>

MATERIALS
<material_name> <material_type>	<eta>	<zeta>	<gamma>	<rho0>	<a0>
(numb_mat lines)

FORCES
<mat#k>	<mat#m>		<sigma>	<shear_slip>	<bulk_slip>
(numb_mat*numb_mat lines, one for each material pair)

sigma is a surface tension coefficient

Initial condition file

    <start time>
    <number of particles>
    ...
    <material name> <X> <Y> <Vx> <Vy> <density> <pressure> <temperature>
    ...

an example

Simulations

Couette flow simulation

$ example/sdpd  cases/couette
$ example/sdpd  cases/couette
The left, right, lower and upper boundary 1 1 0 0
0: wall boundary condition
1: perodic boundary condition
2: free slip wall boundary condition
3: symmetry boundary condition
read the propeties of materials and forces
N=10 Time: 0.00868056	dt: 0.000868056
...

Water drop in air starting from an initial condition file

$ example/sdpd cases/ellipse
The left, right, lower and upper boundary 1 1 0 0
0: wall boundary condition
1: perodic boundary condition
2: free slip wall boundary condition
3: symmetry boundary condition
read the propeties of materials and forces
ini.c:787: Read real particles from 'cases/ellipse.txt'
ini.c:798: N = 576
N=10 Time: 0.778993	dt: 0.000868056
...

Output

Output is in ASCII tecplot files, to convert to punto format run

$ scripts/2punto outdata > punto.dat

Visualization

$ punto -D 2 -V -s 50 punto.dat
$ punto -D 2 -c 4 -B 0:0:0.04:0.04 -G -0.2:0.2 punto.dat

in gnuplot shell

$ plot n=1, 'punto.dat' u 2:3 every :::n::n
$ plot n=10, A=250.0, 'punto.dat' u 2:3 every :::n::n+5, A*x*(L-x)

Images

Poiseuille flow

Ellipsoid water drop in air

Fluctuating liquid

References

• Hu, Xianguy, and Nikolaus A. Adams. "A multi-phase SPH method for macroscopic and mesoscopic flows." Journal of Computational Physics 213.2 (2006): 844-861. https://doi.org/10.1016/j.jcp.2005.09.001

• Litvinov, S., Ellero, M., Hu, X., & Adams, N. A. (2008). Smoothed dissipative particle dynamics model for polymer molecules in suspension. Physical Review E—Statistical, Nonlinear, and Soft Matter Physics, 77(6), 066703.

• Litvinov, S., Ellero, M., Hu, X., & Adams, N. A. (2008). Smoothed dissipative particle dynamics model for polymer molecules in suspension. Physical Review E—Statistical, Nonlinear, and Soft Matter Physics, 77(6), 066703.

• gnuplot http://www.gnuplot.info

• punto http://punto.sourceforge.net

• tecplot http://paulbourke.net/dataformats/tp

• atest https://github.com/slitvinov/atest

• SPH (smoothed-particle hydrodynamics), SDPD (smoothed dissipative particle dynamics)