"Optional title"
sid, overlay
type, gid, follow, $dsf$, ., ., ., $t_{end}$
$\rho_0$, $e_0$, $\gamma$, $v$, $D$
Parameter definition
Variable | Description |
---|---|
sid | Subdomain ID |
overlay | Number of superposed particle layers |
type | High explosive type |
gid | Geometry ID |
follow | Force particles to follow overlapping elements |
$dsf$ | Particle density scale factor (particles per unit volume) |
$t_{end}$ | Particle deactivation time or FUNCTION (fcn) |
$\rho_0$ | 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 > 1 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 > 1 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${}^{1/3}$.