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PARTICLE_SPH_JET

Particle
Attention: This command is in the beta stage and the format may change over time.
*PARTICLE_SPH_JET
sid
$x_1$, $y_1$, $z_1$, $x_2$, $y_2$, $z_2$, $R$, $\xi$
$v_{min}$, $m_{min}$
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
Description

This command is exclusively used when modelling the formation of shaped charge jets.

Numerical noise, from the interaction between SPH nodes and high explosive discrete particles, tends to laterally distort the formed jet. This distortion can be reduced with an increased number of particles. The price to pay is a higher computational cost.

With this command a computationally faster alternative to achieving a straighter jet is offered. It is based on artificially applied lateral impulses. It can be viewed as a method that forces a full 3D model into a more axi-symmetric like behaviour.

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


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


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.