CFD_HE
CFD
*CFD_HE
"Optional title"
sid
type, gid, follow
$\rho$, $A$, $B$, $R_1$, $R_2$, $\omega$, $e_0$, $D$
$e_{ab}$, $t_{ab}$
"Optional title"
sid
type, gid, follow
$\rho$, $A$, $B$, $R_1$, $R_2$, $\omega$, $e_0$, $D$
$e_{ab}$, $t_{ab}$
Parameter definition
Variable
Description
sid
Subdomain ID
type
High explosive type
gid
Geometry ID
follow
Force material in CFD cells to follow the motion of overlapping elements
$\rho$
Density (this line is only used if type=USER)
$A$
JWL coefficient
$B$
JWL coefficient
$R_1$
JWL coefficient
$R_2$
JWL coefficient
$\omega$
JWL coefficient
$e_0$
Internal energy per unit volume, released at detonation
$D$
Detonation velocity
$e_{ab}$
Afterburn energy per unit volume at detonation time
$t_{ab}$
Afterburn time parameter, controlling energy release rate
Description
This command is used to fill a region of the CFD_DOMAIN with a high explosive. Explosives can be detonated using CFD_DETONATION. The pressure is defined as:
$\displaystyle{ p = A \left( 1 - \frac{\omega}{R_1 V} \right) \mathrm{e}^{-R_1 V} + B \left( 1 - \frac{\omega}{R_2 V} \right) \mathrm{e}^{-R_2 V} + \omega e}$
where $V$ is the ratio of current density to initial density and $e$ is the current internal energy per unit volume. The remaining afterburn energy at coordinate $\mathbf{x}$ evolves according to:
$\displaystyle{ \frac{\partial \dot{e}_{ab}}{\partial t} (\mathbf{x},t) = -\frac{e_{ab}(\mathbf{x},t)}{t_{ab}} }$
The follow option is used when switching between a FE formulation for the undetonated explosive and a CFD formulation from detonation time and onwards. This is typically done by syncronizing the deactivation of elements (ACTIVATE_ELEMENTS) and the detonation (CFD_DETONATION).
