PARTICLE_SPH_JET

Particle
Attention: This command is in the beta stage and the format may change over time.
*PARTICLE_SPH_JET
sid
$x_1$, $y_1$, $z_1$, $x_2$, $y_2$, $z_2$, $R$, $\xi$
$v_{min}$, $m_{min}$, no_ecc
Parameter definition
VariableDescription
sid Particle subdomain ID
$x_1$, $y_1$, $z_1$ Cylinder face center coordinate 1
$x_2$, $y_2$, $z_2$ Cylinder face center coordinate 2
$R$ Cylinder radius
$\xi$ Dimensionless jet correction parameter
default: 0.1
$v_{min}$ Cut-off velocity in jet length calculation
default: 0
$m_{min}$ Minimum fragment mass
default: 0
no_ecc Flag to deactivate eccentricity correction
options:
0 $\rightarrow$ eccentricity correction is active
1 $\rightarrow$ eccentricity correction is inactive
Description

This command is exclusively used when modelling the formation of shaped charge jets. Its purpose is to collect and output jet data and to enhance the accuracy of the simulated jet formation process.

The enhancement is based on the assumption that physical variations in the jet diameter have a significantly larger wave length than the distance between individual SPH particles. High frequency surface variations (spatially) are smoothed with a mild surface pressure. The local pressure is only applied locally where non-phyisical surface variations are detected. This prevents a premature jet fragmentation and also results in a straighter jet with a more circular cross section.

The domain where the correction is active is defined as a cylinder in space.


The magnitude of the correction is controlled with a dimensionless parameter $0 \lt \xi \leq 1$. The resulting artificially applied impulse is (together with jet tip velocity and displacement) reported to the file particle_sph_jet.out. The jet tip displacement is calculated from the initial location of the cone base.


Parts of the slug travelling at a velocity smaller than $v_{min}$ (in the jet direction) are omitted from the jet length calculation. Jet tip fragments with a mass smaller than $m_{min}$ are also excluded from the jet length and velocity calculations.