#### PARTICLE_HE

###### Particle
*PARTICLE_HE
"Optional title"
sid, overlay
type, gid, follow, $dsf$, ., ., ., $t_{end}$
$\rho_0$, $e_0$, $\gamma$, $v$, $D$
##### Parameter definition
VariableDescription
sid Subdomain ID
overlay Number of superposed particle layers
default: not active
type High explosive type
options:
TNT $\rightarrow$ TNT
C4 $\rightarrow$ Comp C-4
PETN $\rightarrow$ pentaerythritol tetranitrate
m46 $\rightarrow$ m46
HMX $\rightarrow$ HMX
CompA $\rightarrow$ Comp A-3
CompB $\rightarrow$ Comp B (grade A)
Octol $\rightarrow$ Octol 78/22
LX-10-1 $\rightarrow$ LX-10-1
LX-14-0 $\rightarrow$ LX-14-0
PBXN-9010 $\rightarrow$ PBXN-9010
Tetryl $\rightarrow$ Tetryl
ANFO $\rightarrow$ Ammonium nitrate fuel oil
PBXN-110 $\rightarrow$ PBXN-110
MCX-6100 $\rightarrow$ MCX-6100
NSP-711 $\rightarrow$ NSP-711
USER $\rightarrow$ user defined
gid Geometry ID
options:
0 $\rightarrow$ no
1 $\rightarrow$ yes
$dsf$ Particle density scale factor (particles per unit volume)
default: 1
$t_{end}$ Particle deactivation time or FUNCTION (fcn)
options: time or fcn
default: not used
$\rho_0$ Density (this line is only used if type=USER)
$e_0$ Energy per unit volume
$\gamma$ Fraction between C${}_\mathrm{p}$ and C${}_\mathrm{v}$ at zero co-volume (ideal gas regime)
$v$ Co-volume at $\rho = \rho_0$
$D$ Detonation velocity
##### Description

Discrete particle high explosive domain definition.

The subdomain ID (sid) determines in which order particles are filled into the global domain. In case subdomains are overlapping, the domain with the largest ID will overwrite (remove) particles belonging to domains with lower domain ID's.

The follow flag can be used when gid is a GEOMETRY_PART. Setting follow=1 forces the particles to follow the motion of the finite elements (where they are embedded). Note that the elements and the particles represent the same material. Elements are active prior to erosion and the particles are active after erosion. This feature is typically used to model undetonated explosive material with Finite Elements. At detonation the elements are eroded (e.g. ACTIVATE_ELEMENTS) and replaced by the particles.

$1 \lt \gamma \leq 5/3$ determines the ratio $\xi$ between thermal translational energy and molecular spin + vibrational energy.

$\displaystyle{ \xi = \frac{3}{2}(\gamma - 1) }$

overlay $\geq 2$ is an optional integer parameter. If used, then the explosive is subdivided into multiple, superposed, layers. Explosive particles in different layers do not interact with each other. overlay $\geq 2$ results in a larger high explosive particle radius and a larger time step size during the detonation phase. A negative side effect is a smeared out shock front. Both the time step size and the shock front width are proportional to overlay${}^{1/3}$.