Physical separation in debris

[Nikesh Kumar Ojha]

Hello all,

I am simulating debris formation in target plate using hypervelocity impact. I observed there is a physical separation in debris (Screenshot attached) during simulation. I want to know why this separation occurs in debris. Is my debris formation is correct or there is any error?

Please share your valuable suggestions. Your suggestions will be highly appreciated.

For reference: Keywords attached

*CONTROL_SPH
$#    ncbs     boxid        dt      idim   nmneigh      form     start      maxv
            1            1     1.0E20         3       150                0          0.0      1.0E15
$#    cont     deriv       ini     ishow     ierod     icont     iavis     isymp
             0           0            0         0            0           0            0         100
$#    ithk     istab        ql         -   sphsort      
             0         0         0.01      0         0

*SECTION_SPH_TITLE
sph_projectile
$#   secid      cslh      hmin      hmax    sphini     death     start   sphkern
              3       1.2          0.2         2.0          0.0       1.0E20     0.0         0

Regards 

Nikesh

[l...@schwer.net]

Hello Nikesh –

 

1\ This simulation would best be performed as an axisymmetric IDIM=-2, or at a minimum take advantage of the double symmetry and only model one quarter of the simulation.

Such a reduced dimension model may remove the particle separation you observe.

 

2\ Since your simulation is fully 3D (IDIM=3), is the particle separation you observe only in one plane, i.e. a “V” shaped or is it axisymmetric, i.e.  conical?

 

3\ The physics of this debris flow is to form a spherically expansion of the particles. So once the “lead” two particles move a sufficient distance away from the symmetry axis, they lose connectivity with each other and the “split” starts and continues. I would experiment with increasing subsequent smoothing length via increased value of HMAX on *SECTION_SPH.

 

4\ Have you tried other SPH formulations, e.g. FORM=1 on keyword *CONTROL_SPH?

 

                --len

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